Identifying injection drug use and estimating population size of people who inject drugs using healthcare administrative datasets

The effect of Montreal's supervised consumption sites on injection-related infections among people who inject drugs: An interrupted time series

BACKGROUND

Between June and November 2017, four supervised consumption sites (SCS) began operating in Montreal, Quebec. Earlier studies on SCS focused on examining their effects on blood-borne viral infections and overdose mortality. Our objective was to examine the effect of Montreal's SCS on the incidence, health service use and outcomes of injection-related infections (IRI) in people who inject drugs.

METHODS

We used Quebec's provincial administrative health data to identify people who inject drugs in Montreal and calculated the incidence of IRI in this population between December 2014 and December 2019. We conducted a retrospective, population-based interrupted time series to estimate the effect of Montreal's four SCS on the monthly incidence rates of IRI-related hospitalizations, emergency department (ED) visits, physician visits, and mortality. We also examined the effects of SCS on average length of IRI-related hospitalizations and incidence of hospitalizations involving surgery.

RESULTS

The average age of Montreal's people who inject drugs was 41.84 years, and 66.41% were male. After the implementation of SCS, there was a positive level change in the incidence of hospitalizations (0.97; 95% confidence interval [CI]: 0.26, 1.68) for IRI. There was also a significant post-intervention decline in hospitalization trends (-0.05; 95% CI: -0.08, -0.02), with modest trend changes in ED visits (-0.02; 95% CI: -0.05, 0.02). However, post-intervention changes in level (0.72; 95% CI: -3.85, 5.29) and trend (0.06; 95% CI: -0.23, 0.34) for physician visits remained limited. SCS had no effect on the average length of hospitalizations, but there was a decreasing post-intervention trend in hospitalizations involving surgery (-0.03; 95% CI: -0.06, 0.00).

CONCLUSION

Following the opening of the SCS, there was a moderate decline in the rate of hospitalizations to treat IRI, but the impact of the sites on the rate of physician visits remained limited. These findings suggest that SCS may mitigate the incidence of more serious and complicated IRI over time.

Association of hepatitis B virus treatment with all-cause and liver-related mortality among individuals with HBV and cirrhosis: a population-based cohort study

Background

We evaluated the association of hepatitis B virus (HBV) treatment with all-cause, and liver-related mortality among individuals with HBV and cirrhosis in British Columbia (BC), Canada.

Methods

This analysis included people diagnosed with HBV and had cirrhosis in the BC Hepatitis Testers Cohort, including data on all individuals diagnosed with HBV from 1990 to 2015 in BC and integrated with healthcare administrative data. We followed people with cirrhosis from the first cirrhosis diagnosis date until death or December 31, 2020. We compared all-cause and liver related mortality between those who received treatment and those who did not. HBV treatment was considered a time-varying variable. We performed multivariable Cox proportional hazards model and competing risk regression models to assess the association of HBV treatment with all causes, and liver-related mortality respectively using inverse probability of treatment weighted population.

Findings

Among 4962 individuals with HBV and cirrhosis, 48.1% received HBV treatment. Treated individuals had a median follow-up of 2.97 years, compared to 2.87 years for untreated individuals. The treated group was older (median age 57 vs 54 years), had higher proportion of treated of males [1802 (75.50%) vs 1766 (68.8%)], from urban area [2318 (97.2%) vs 2355 (91.8%)], and from East and South Asian ethnicity [1506 (63.1%) vs 709 (27.5%)] compared to untreated group. Untreated people experienced higher all-cause mortality (115.47 vs. 35.72 per 1000 person-years) and liver-related mortality (49.86 vs. 11.39 per 1000 person-years). Multivariable models showed that HBV treatment significantly lowered the risk of all-cause mortality (adjusted hazard ratio (aHR) 0.74; 95% CI: 0.65, 0.84) and liver-related mortality (adjusted subdistribution hazard ratio (asHR) 0.72; 95% CI: 0.58, 0.89) compared to untreated individuals. Among untreated individuals with HBV, those with HCV coinfection had a higher risk of both all-cause and liver-related mortality (aHR 1.57; 95% CI: 1.22, 2.04, and asHR 1.60; 95% CI: 1.25, 2.05, respectively).

Interpretation

HBV treatment was associated with a significant reduction in all-cause and liver-related mortality among individuals with cirrhosis. The findings highlight the need for treatment among individuals with HBV related cirrhosis especially those with coinfection with hepatitis C virus.

Funding

This work was supported by the BC Centre for Disease Control and the Canadian Institutes of Health Research (CIHR) [Grant # NHC-142832, PJT-156066, and SC1 -178736]. JDM has received doctoral fellowship from the Canadian Network on Hepatitis C (CanHepC). DJ has received Doctoral Research Award (#201910DF1-435705-64343) from the Canadian Institutes of Health Research (CIHR) and doctoral fellowship from the CanHepC. CanHepC is funded by a joint initiative of the Canadian Institutes of Health Research (CIHR) (NHC-142832) and the Public Health Agency of Canada (PHAC).

Factors associated with hepatitis C treatment uptake among females of childbearing age in New South Wales, Australia: A population-based study

INTRODUCTION

Females of childbearing age with hepatitis C virus (HCV) face increased marginalisation with intersecting, sex-specific barriers to direct acting antiviral (DAA) therapy. We assessed the factors associated with uptake of DAA therapy among females of childbearing age, including those with evidence of recent drug dependence.

METHODS

HCV notifications in New South Wales, Australia (1995-2017) were linked to opioid agonist therapy (OAT), hospitalisations, incarcerations, perinatal, HIV notifications, deaths and prescription databases. Recent drug dependence was defined as hospitalisation due to injectable drugs or receipt of OAT occurring in the DAA era (2016-2018). Logistic regression was used to analyse factors associated with DAA uptake among females of childbearing age (18-44), including those with recent drug dependence.

RESULTS

Among 57,467 people with evidence of chronic HCV in the DAA era (2016-2018), 20,161 (35%) were female, including 33% (n = 6563/20,161) of childbearing age (18-44). Among all females of childbearing age (n = 6563) and those with evidence of recent drug dependence (n = 2278/6563, 35%), DAA uptake was lower among those who had given birth in the DAA era (vs. no birth record, all females of childbearing age; aOR: 0.74, 95% CI 0.61, 0.89; those with recent drug dependence; aOR 0.69, 95% CI 0.51, 0.93) and Aboriginal and Torres Strait Islander peoples (all females of childbearing age; aOR 0.81, 95% CI 0.71, 0.93; those with recent drug dependence aOR 0.75, 95% CI 0.62, 0.90).

CONCLUSION

Females of childbearing age should be considered a key population for DAA therapy. Enhancing antenatal and postnatal HCV care may be critical in the pursuit towards elimination.

Economic evaluation of the effect of needle and syringe programs on skin, soft tissue, and vascular infections in people who inject drugs: a microsimulation modelling approach

BACKGROUND

Needle and syringe programs (NSP) are effective harm-reduction strategies against HIV and hepatitis C. Although skin, soft tissue, and vascular infections (SSTVI) are the most common morbidities in people who inject drugs (PWID), the extent to which NSP are clinically and cost-effective in relation to SSTVI in PWID remains unclear. The objective of this study was to model the clinical- and cost-effectiveness of NSP with respect to treatment of SSTVI in PWID.

METHODS

We performed a model-based, economic evaluation comparing a scenario with NSP to a scenario without NSP. We developed a microsimulation model to generate two cohorts of 100,000 individuals corresponding to each NSP scenario and estimated quality-adjusted life-years (QALY) and cost (in 2022 Canadian dollars) over a 5-year time horizon (1.5% per annum for costs and outcomes). To assess the clinical effectiveness of NSP, we conducted survival analysis that accounted for the recurrent use of health care services for treating SSTVI and SSTVI mortality in the presence of competing risks.

RESULTS

The incremental cost-effectiveness ratio associated with NSP was $70,278 per QALY, with incremental cost and QALY gains corresponding to $1207 and 0.017 QALY, respectively. Under the scenario with NSP, there were 788 fewer SSTVI deaths per 100,000 PWID, corresponding to 24% lower relative hazard of mortality from SSTVI (hazard ratio [HR] = 0.76; 95% confidence interval [CI] = 0.72-0.80). Health service utilization over the 5-year period remained lower under the scenario with NSP (outpatient: 66,511 vs. 86,879; emergency department: 9920 vs. 12,922; inpatient: 4282 vs. 5596). Relatedly, having NSP was associated with a modest reduction in the relative hazard of recurrent outpatient visits (HR = 0.96; 95% CI = 0.95-0.97) for purulent SSTVI as well as outpatient (HR = 0.88; 95% CI = 0.87-0.88) and emergency department visits (HR = 0.98; 95% CI = 0.97-0.99) for non-purulent SSTVI.

CONCLUSIONS

Both the individuals and the healthcare system benefit from NSP through lower risk of SSTVI mortality and prevention of recurrent outpatient and emergency department visits to treat SSTVI. The microsimulation framework provides insights into clinical and economic implications of NSP, which can serve as valuable evidence that can aid decision-making in expansion of NSP services.

Validation of case-ascertainment algorithms using health administrative data to identify people who inject drugs in Ontario, Canada

OBJECTIVES

Health administrative data can be used to improve the health of people who inject drugs by informing public health surveillance and program planning, monitoring, and evaluation. However, methodological gaps in the use of these data persist due to challenges in accurately identifying injection drug use (IDU) at the population level. In this study, we validated case-ascertainment algorithms for identifying people who inject drugs using health administrative data in Ontario, Canada.

STUDY DESIGN AND SETTING

Data from cohorts of people with recent (past 12 months) IDU, including those participating in community-based research studies or seeking drug treatment, were linked to health administrative data in Ontario from 1992 to 2020. We assessed the validity of algorithms to identify IDU over varying look-back periods (ie, all years of data [1992 onwards] or within the past 1-5 years), including inpatient and outpatient physician billing claims for drug use, emergency department (ED) visits or hospitalizations for drug use or injection-related infections, and opioid agonist treatment (OAT).

RESULTS

Algorithms were validated using data from 15,241 people with recent IDU (918 in community cohorts and 14,323 seeking drug treatment). An algorithm consisting of ≥1 physician visit, ED visit, or hospitalization for drug use, or OAT record could effectively identify IDU history (91.6% sensitivity and 94.2% specificity) and recent IDU (using 3-year look back: 80.4% sensitivity, 99% specificity) among community cohorts. Algorithms were generally more sensitive among people who inject drugs seeking drug treatment.

CONCLUSION

Validated algorithms using health administrative data performed well in identifying people who inject drugs. Despite their high sensitivity and specificity, the positive predictive value of these algorithms will vary depending on the underlying prevalence of IDU in the population in which they are applied.

Impact of the COVID-19 Pandemic on Hepatitis C Treatment Initiation in British Columbia, Canada: An Interrupted Time Series Study

We investigated the impacts of the COVID-19 pandemic on hepatitis C (HCV) treatment initiation, including by birth cohort and injection drug use status, in British Columbia (BC), Canada. Using population data from the BC COVID-19 Cohort, we conducted interrupted time series analyses, estimating changes in HCV treatment initiation following the introduction of pandemic-related policies in March 2020. The study included a pre-policy period (April 2018 to March 2020) and three follow-up periods (April to December 2020, January to December 2021, and January to December 2022). The level of HCV treatment initiation decreased by 26% in April 2020 (rate ratio 0.74, 95% confidence interval [CI] 0.60 to 0.91). Overall, no statistically significant difference in HCV treatment initiation occurred over the 2020 and 2021 post-policy periods, and an increase of 34.4% (95% CI 0.6 to 75.8) occurred in 2022 (equating to 321 additional people initiating treatment), relative to expectation. Decreases in HCV treatment initiation occurred in 2020 for people born between 1965 and 1974 (25.5%) and people who inject drugs (24.5%), relative to expectation. In summary, the pandemic was associated with short-term disruptions in HCV treatment initiation in BC, which were greater for people born 1965 to 1974 and people who inject drugs.

Ongoing Gaps in the Hepatitis C Care Cascade during the Direct-Acting Antiviral Era in a Large Retrospective Cohort in Canada: A Population-Based Study

To achieve hepatitis C virus (HCV) elimination, high uptake along the care cascade steps for all will be necessary. We mapped engagement with the care cascade overall and among priority groups in the post-direct-acting antivirals (DAAs) period and assessed if this changed relative to pre-DAAs. We created a population-based cohort of all reported HCV diagnoses in Quebec (1990-2018) and constructed the care cascade [antibody diagnosed, RNA tested, RNA positive, genotyped, treated, sustained virologic response (SVR)] in 2013 and 2018. Characteristics associated with RNA testing and treatment initiation were investigated using marginal logistic models via generalized estimating equations. Of the 31,439 individuals HCV-diagnosed in Quebec since 1990 and alive as of 2018, there was significant progress in engagement with the care cascade post- vs. pre-DAAs; 86% vs. 77% were RNA-tested, and 64% vs. 40% initiated treatment. As of 2018, a higher risk of not being RNA-tested or treated was observed among individuals born <1945 vs. >1965 [hazard ratio (HR); 95% CI; 1.35 (1.16-1.57)], those with material and social deprivation [1.21 (1.06-1.38)], and those with alcohol use disorder [1.21 (1.08-1.360]. Overall, non-immigrants had lower rates of RNA testing [0.76 (0.67-0.85)] and treatment initiation [0.63 (0.57-0.70)] than immigrants. As of 2018, PWID had a lower risk of not being RNA tested [0.67 (0.61-0.85)] but a similar risk of not being treated, compared to non-PWID. Engagement in the HCV care cascade have improved in the post-DAA era, but inequities remain. Vulnerable subgroups, including certain older immigrants, were less likely to have received RNA testing or treatment as of 2018 and would benefit from focused interventions to strengthen these steps.

Mortality associated with bacterial and fungal infections and overdose among people with drug use diagnoses

PURPOSE

Hospital visits for drug use-related bacterial and fungal infections have increased alongside overdose deaths. The incidence of mortality from these infections and the comparison to overdose mortality is not established.

METHODS

This cohort study examined mortality outcomes among adults with drug use diagnoses who were insured by public and private plans during 2007 through 2018 in North Carolina. We examined bacterial- and fungal infection-related mortality and overdose mortality using cumulative incidence functions.

RESULTS

Among 131,522 people with drug use diagnoses, the median age was 45 years (interquartile range: 31-57), 58% were women and 65% had an opioid use disorder diagnosis. The 1-year incidence of bacterial and fungal infection-associated mortality was progressively higher as age increased (35-49 years: 9 per 10,000 people, 50-64 years: 23 per 10,000, 65+ years: 50 per 10,000 people). Conversely, the 1-year incidence of overdose mortality was markedly lower among older adults compared to those under the age of 65 (18-34 years: 34 deaths per 10,000 people; 35-49 years: 47 per 10,000; 50-64 years: 41 per 10,000; 65+ years: 9 per 10,000).

CONCLUSIONS

Bacterial and fungal infections and overdose were notable causes of death among adults with drug use diagnoses, and varied by age group.

HIV and HCV testing at clinical encounters among people who inject drugs, 2013-2018-Opportunities for increased testing and prevention

People who inject drugs (PWID) with unsafe injection practices have substantial risk for HIV and hepatitis C virus (HCV) infections. We describe frequency of, and factors associated with, HIV and HCV testing during clinical encounters with PWID. Inpatient and Emergency Department clinical encounters at an Atlanta hospital were abstracted from medical records spanning January 2013-December 2018. We estimated frequency of HIV and HCV testing during injection drug use (IDU)-related encounters among PWID without previous diagnoses. We assessed associations between patient factors and testing using generalized estimating equations models. HIV testing occurred in 39.3% and HCV testing occurred in 17.1% of eligible IDU-related encounters. Testing was more likely in IDU-related encounters during 2017-2018 than in encounters during 2013-2014; (HIV, AOR = 2.14, 95% CI, 1.32-3.49, p < .01). Testing was less likely among Black/African American patients compared to White patients (adjusted odds ratio [AOR]: HIV, AOR = 0.48, 95% confidence interval [CI], 0.33-0.72, p < .01); HCV, AOR = 0.41, 95% CI, 0.24-0.70, p < .01). This difference may be attributable to recent testing among Black patients in non-IDU related encounters. HIV and HCV testing improved over time; however, missed opportunities for testing still existed. Strategies should aim to improve equitable HIV and HCV testing among PWID.

Risk of COVID-19 hospitalization in people living with HIV and HIV-negative individuals and the role of COVID-19 vaccination: A retrospective cohort study

OBJECTIVE

To examine the risk of hospitalization within 14 days of COVID-19 diagnosis among people living with HIV (PLWH) and HIV-negative individuals who had laboratory-confirmed SARS-CoV-2 infection.

METHODS

We used Cox proportional hazard models to compare the relative risk of hospitalization in PLWH and HIV-negative individuals. Then, we used propensity score weighting to examine the influence of sociodemographic factors and comorbid conditions on risk of hospitalization. These models were further stratified by vaccination status and pandemic period (pre-Omicron: December 15, 2020, to November 21, 2021; Omicron: November 22, 2021, to October 31, 2022).

RESULTS

The crude hazard ratio (HR) for risk of hospitalization in PLWH was 2.44 (95% confidence interval [CI]: 2.04-2.94). In propensity score-weighted models that included all covariates, the relative risk of hospitalization was substantially attenuated in the overall analyses (adjusted HR [aHR]: 1.03; 95% CI: 0.85-1.25), in vaccinated (aHR 1.00; 95% CI: 0.69-1.45), inadequately vaccinated (aHR: 1.04; 95% CI: 0.76-1.41) and unvaccinated individuals (aHR: 1.15; 95% CI: 0.84-1.56).

CONCLUSION

PLWH had about two times the risk of COVID-19 hospitalization than HIV-negative individuals in crude analyses which attenuated in propensity score-weighted models. This suggests that the risk differential can be explained by sociodemographic factors and history of comorbidity, underscoring the need to address social and comorbid vulnerabilities (e.g., injecting drugs) that were more prominent among PLWH.

COVID-19 vaccine effectiveness by HIV status and history of injection drug use: a test-negative analysis

INTRODUCTION

People living with HIV (PLWH) and/or who inject drugs may experience lower vaccine effectiveness (VE) against SARS-CoV-2 infection.

METHODS

A validated algorithm was applied to population-based, linked administrative datasets in the British Columbia COVID-19 Cohort (BCC19C) to ascertain HIV status and create a population of PLWH and matched HIV-negative individuals. The study population was limited to individuals who received an RT-PCR laboratory test for SARS-CoV-2 between 15 December 2020 and 21 November 2021 in BC, Canada. Any history of injection drug use (IDU) was ascertained using a validated administrative algorithm. We used a test-negative study design (modified case-control analysis) and multivariable logistic regression to estimate adjusted VE by HIV status and history of IDU.

RESULTS

Our analysis included 2700 PLWH and a matched population of 375,043 HIV-negative individuals, among whom there were 351 and 103,049 SARS-CoV-2 cases, respectively. The proportion of people with IDU history was much higher among PLWH compared to HIV-negative individuals (40.7% vs. 4.3%). Overall VE during the first 6 months after second dose was lower among PLWH with IDU history (65.8%, 95% CI = 43.5-79.3) than PLWH with no IDU history (80.3%, 95% CI = 62.7-89.6), and VE was particularly low at 4-6 months (42.4%, 95% CI = -17.8 to 71.8 with IDU history vs. 64.0%; 95% CI = 15.7-84.7 without), although confidence intervals were wide. In contrast, overall VE was 88.6% (95% CI = 88.2-89.0) in the matched HIV-negative population with no history of IDU and remained relatively high at 4-6 months after second dose (84.6%, 95% CI = 83.8-85.4). Despite different patterns of vaccine protection by HIV status and IDU history, peak estimates were similar (≥88%) across all populations.

CONCLUSIONS

PLWH with a history of IDU may experience lower VE against COVID-19 infection, although findings were limited by a small sample size. The lower VE at 4-6 months may have implications for booster dose prioritization for PLWH and people who inject drugs. The immunocompromising effect of HIV, substance use and/or co-occurring comorbidities may partly explain these findings.

Hepatitis C Treatment Initiation Among US Medicaid Enrollees

IMPORTANCE

Direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) infection is highly effective but remains underused. Understanding disparities in the delivery of DAAs is important for HCV elimination planning and designing interventions to promote equitable treatment.

OBJECTIVE

To examine variations in the receipt of DAA in the 6 months following a new HCV diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used national Medicaid claims from 2017 to 2019 from 50 states, Washington DC, and Puerto Rico. Individuals aged 18 to 64 years with a new diagnosis of HCV in 2018 were included. A new diagnosis was defined as a claim for an HCV RNA test followed by an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) diagnosis code, after a 1-year lookback period.

MAIN OUTCOMES AND MEASURES

Outcome was receipt of a DAA prescription within 6 months of diagnosis. Logistic regression was used to examine demographic factors and ICD-10-identified comorbidities associated with treatment initiation.

RESULTS

Among 87 652 individuals, 43 078 (49%) were females, 12 355 (14%) were age 18 to 29 years, 35 181 (40%) age 30 to 49, 51 282 (46%) were non-Hispanic White, and 48 840 (49%) had an injection drug use diagnosis. Of these individuals, 17 927 (20%) received DAAs within 6 months of their first HCV diagnosis. In the regression analyses, male sex was associated with increased treatment initiation (OR, 1.24; 95% CI, 1.16-1.33). Being age 18 to 29 years (OR, 0.65; 95% CI, 0.50-0.85) and injection drug use (OR, 0.84; 95% CI, 0.75-0.94) were associated with decreased treatment initiation. After adjustment for state fixed effects, Asian race (OR, 0.50; 95% CI, 0.40-0.64), American Indian or Alaska Native race (OR, 0.68; 95% CI, 0.55-0.84), and Hispanic ethnicity (OR, 0.81; 95% CI, 0.71-0.93) were associated with decreased treatment initiation. Adjustment for state Medicaid policy did not attenuate the racial or ethnic disparities.

CONCLUSIONS

In this retrospective cohort study, HCV treatment initiation was low among Medicaid beneficiaries and varied by demographic characteristics and comorbidities. Interventions are needed to increase HCV treatment uptake among Medicaid beneficiaries and to address disparities in treatment among key populations, including younger individuals, females, individuals from minoritized racial and ethnic groups, and people who inject drugs.

Hepatitis C Virus Testing and Care Cascade Among Transgender and Gender Diverse Individuals

INTRODUCTION

Hepatitis C virus (HCV) prevalence among transgender and gender-diverse individuals ranges from 1.8% to 15.7% versus 1% in the general population. Previous HCV studies inclusive of transgender and gender-diverse individuals primarily rely on convenience-based sampling methods or are geographically restricted. The purpose of this study is to compare the prevalence of HCV diagnoses, testing, and care engagement between transgender and gender-diverse and cisgender individuals.

METHODS

Using Optum's de-identified Clinformatics® Data Mart Database, in 2022, the unadjusted prevalence of HCV testing among all adults and people who inject drugs from January 2001 to December 2019 was measured. Multivariable logistic regression was used to compare the adjusted odds of HCV diagnoses and care engagement by gender subgroup.

RESULTS

The overall unadjusted frequency of HCV diagnoses among transgender and gender-diverse individuals was approximately 3 times that of cisgender individuals (1.06% vs 0.38%, p<0.001), including among people who inject drugs (6.36% vs 2.36%, p=0.007). Compared with cisgender women, transfeminine/nonbinary individuals had over 5 times the adjusted odds of a HCV diagnosis and approximately 3.5 times the odds of being tested for HCV. In addition, compared with cisgender women, transfeminine/nonbinary individuals had significantly increased odds of having a HCV‒related procedure (e.g., abdominal ultrasounds, liver biopsies, Fibroscans). Cisgender men had significantly increased odds of receiving HCV medication compared with cisgender women.

CONCLUSIONS

Although testing was higher among transgender and gender-diverse individuals, the higher overall frequency of HCV diagnoses among transgender and gender-diverse than among cisgender individuals signals persistent health disparities. Interventions are warranted to prevent HCV and increase ongoing testing and treatment uptake among transgender and gender-diverse populations.

Missed opportunities for prevention: prevalence and incidence of human immunodeficiency virus and hepatitis C virus diagnoses among a cohort of individuals discharged from an urban hospital with injection drug-related diagnoses, 2012-2019

PURPOSE

Risk for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections has increased due to the ongoing opioid epidemic and unsafe injection practices. We estimated the prevalence and incidence of HIV and HCV diagnoses among people who inject drugs from hospital-based clinical encounters.

METHODS

We linked clinical encounters at an Atlanta hospital during 2012-2018 with state HIV and HCV surveillance records to examine the prevalence of infections at discharge and incidence of infections post clinical encounter.

RESULTS

At discharge, 32.9% and 28.6% of patients with injection drug use-related clinical encounters had an HIV or HCV diagnosis, respectively. HIV and HCV diagnoses at the time of discharge were mostly among 40-64 years old patients, males, and Black/African Americans. Post clinical encounter, 3.8% of patients were later diagnosed with HIV, and 16.5% were later diagnosed with HCV, translating to incidence rates of 9.3 per 1000 person-years and 41.5 per 1000 person-years, respectively. The majority of HIV and HCV diagnoses post clinical encounter occurred among Black/African Americans and males. Of patients with HIV and HCV diagnoses post clinical encounter, 27.3% and 11.9% had been tested during their clinical encounter, respectively.

CONCLUSIONS

Targeted interventions for HIV/HCV prevention, screening, diagnosis, and linkage to treatment are needed to reduce the incidence of new infections among people who inject drugs.

Comparative Safety Analysis of Opioid Agonist Treatment in Pregnant Women with Opioid Use Disorder: A Population-Based Study

INTRODUCTION AND OBJECTIVE

Receipt of opioid agonist treatment during early and late pregnancy for opioid use disorder may relate to varying perinatal risks. We aimed to assess the effect of time-varying prenatal exposure to opioid agonist treatment using buprenorphine or methadone on adverse neonatal and pregnancy outcomes.

METHODS

We conducted a retrospective cohort study of pregnant women with opioid use disorder using Rhode Island Medicaid claims data and vital statistics during 2008-16. Time-varying exposure was evaluated in early (0-20 weeks) and late (≥ 21 weeks) pregnancy. Marginal structural models with inverse probability of treatment weighting were applied.

RESULTS

Of 400 eligible pregnancies, 85 and 137 individuals received buprenorphine and methadone, respectively, during early pregnancy. Compared with 152 untreated pregnancies with opioid use disorders, methadone exposure in both periods was associated with an increased risk of preterm birth (adjusted odds ratio [aOR]: 2.52; 95% confidence interval [CI] 1.07-5.95), low birth weight (aOR: 2.99; 95% CI 1.34-6.66), neonatal intensive care unit admission (aOR, 5.04; 95% CI 2.49-10.21), neonatal abstinence syndrome (aOR: 11.36; 95% CI 5.65-22.82), respiratory symptoms (aOR, 2.71; 95% CI 1.17-6.24), and maternal hospital stay > 7 days (aOR, 14.51; 95% CI 7.23-29.12). Similar patterns emerged for buprenorphine regarding neonatal abstinence syndrome (aOR: 10.27; 95% CI 4.91-21.47) and extended maternal hospital stay (aOR: 3.84; 95% CI 1.83-8.07). However, differences were found favoring the use of buprenorphine for preterm birth versus untreated pregnancies (aOR: 0.17; 95% CI 0.04-0.77), and for several outcomes versus methadone.

CONCLUSIONS

Methadone and buprenorphine prescribed for the treatment of opioid use disorder during pregnancy are associated with varying perinatal risks. However, buprenorphine may be preferred in the setting of pregnancy opioid agonist treatment. Further research is necessary to confirm our findings and minimize residual confounding.

Disparities in Access to Hepatitis C Treatment Among Arizona Medicaid Beneficiaries With Chronic Hepatitis C

BACKGROUND

High costs of direct-acting antivirals (DAAs) have led to their restricted access for patients with hepatitis C virus (HCV).

OBJECTIVE

The aim was to assess how HCV treatment access and predictors of HCV treatment changed in the post-DAA period compared with pre-DAA period.

METHODS

A retrospective cohort study using Arizona Medicaid data was conducted for patients with HCV to compare treatment initiation rates between pre-DAA (January 2008-October 2013) and post-DAA (November 2013-December 2018) periods. Multivariable logistic regression was used, controlling for demographic and clinical variables.

RESULTS

Twenty-four thousand and ninety and 28,756 patients during the pre-DAA and post-DAA periods were identified. Overall, 12.6% were treated in the post-DAA period compared with 7.8% in the pre-DAA period ( P <0.001). The relative increase in the HCV treatment initiation rate from the pre-DAA to the post-DAA period was significant greater for Black beneficiaries compared with White beneficiaries ( P =0.002). Hispanic beneficiaries were less likely to be treated in the post-DAA period [adjusted odds ratios (aOR): 0.88; CI: 0.79-0.98] compared with White beneficiaries. Those with mental illness (aOR: 0.71; 95% CI: 0.63-0.80) and substance use disorders (aOR: 0.63; 95% CI: 0.58-0.68) were less likely to be treated in the post-DAA period.

CONCLUSIONS

Although treatment initiation increased and disparities for Black beneficiaries compared with White beneficiaries attenuated in the post-DAA period, only 13% of Arizona Medicaid patients with HCV received DAA treatment. Disparities in DAA access remained among Hispanic patients and those with mental illness and substance use disorders.

Effectiveness of COVID-19 vaccines in people living with HIV in British Columbia and comparisons with a matched HIV-negative cohort: a test-negative design

OBJECTIVES

We estimated the effectiveness of COVID-19 vaccines against laboratory-confirmed SARS-CoV-2 infection among people living with HIV (PLWH) and compared the estimates with a matched HIV-negative cohort.

METHODS

We used the British Columbia COVID-19 Cohort, a population-based data platform, which integrates COVID-19 data on SARS-CoV-2 tests, laboratory-confirmed cases, and immunizations with provincial health services data. The vaccine effectiveness (VE) was estimated with a test-negative design using the multivariable logistic regression.

RESULTS

The adjusted VE against SARS-CoV-2 infection was 71.1% (39.7, 86.1%) 7-59 days after two doses, rising to 89.3% (72.2, 95.9%) between 60 and 89 days. VE was preserved 4-6 months after the receipt of two doses, after which noticeable waning was observed (51.3% [4.8, 75.0%]). In the matched HIV-negative cohort (n = 375,043), VE peaked at 91.4% (90.9, 91.8%) 7-59 days after two doses and was sustained for up to 4 months, after which evidence of waning was observed, dropping to 84.2% (83.4, 85.0%) between 4 and 6 months.

CONCLUSION

The receipt of two COVID-19 vaccine doses was effective against SARS-CoV-2 infection among PLWH pre-Omicron. VE estimates appeared to peak later in PLWH than in the matched HIV-negative cohort and the degree of waning was relatively quicker in PLWH; however, peak estimates were comparable in both populations.

Discontinuation and tapering of prescribed opioids and risk of overdose among people on long-term opioid therapy for pain with and without opioid use disorder in British Columbia, Canada: A retrospective cohort study

BACKGROUND

The overdose crisis in North America has prompted system-level efforts to restrict opioid prescribing for chronic pain. However, little is known about how discontinuing or tapering prescribed opioids for chronic pain shapes overdose risk, including possible differential effects among people with and without concurrent opioid use disorder (OUD). We examined associations between discontinuation and tapering of prescribed opioids and risk of overdose among people on long-term opioid therapy for pain, stratified by diagnosed OUD and prescribed opioid agonist therapy (OAT) status.

METHODS AND FINDINGS

For this retrospective cohort study, we used a 20% random sample of residents in the provincial health insurance client roster in British Columbia (BC), Canada, contained in the BC Provincial Overdose Cohort. The study sample included persons aged 14 to 74 years on long-term opioid therapy for pain (≥90 days with ≥90% of days on therapy) between October 2014 and June 2018 (n = 14,037). At baseline, 7,256 (51.7%) persons were female, the median age was 55 years (quartile 1-3: 47-63), 227 (1.6%) persons had been diagnosed with OUD (in the past 3 years) and recently (i.e., in the past 90 days) been prescribed OAT, and 483 (3.4%) had been diagnosed with OUD but not recently prescribed OAT. The median follow-up duration per person was 3.7 years (quartile 1-3: 2.6-4.0). Marginal structural Cox regression with inverse probability of treatment weighting (IPTW) was used to estimate the effect of prescribed opioid treatment for pain status (discontinuation versus tapered therapy versus continued therapy [reference]) on risk of overdose (fatal or nonfatal), stratified by the following groups: people without diagnosed OUD, people with diagnosed OUD receiving OAT, and people with diagnosed OUD not receiving OAT. In marginal structural models with IPTW adjusted for a range of demographic, prescription, comorbidity, and social-structural exposures, discontinuing opioids (i.e., ≥7-day gap[s] in therapy) was associated with increased overdose risk among people without OUD (adjusted hazard ratio [AHR] = 1.44; 95% confidence interval [CI] 1.12, 1.83; p = 0.004), people with OUD not receiving OAT (AHR = 3.18; 95% CI 1.87, 5.40; p < 0.001), and people with OUD receiving OAT (AHR = 2.52; 95% CI 1.68, 3.78; p < 0.001). Opioid tapering (i.e., ≥2 sequential decreases of ≥5% in average daily morphine milligram equivalents) was associated with decreased overdose risk among people with OUD not receiving OAT (AHR = 0.31; 95% CI 0.14, 0.67; p = 0.003). The main study limitations are that the outcome measure did not capture overdose events that did not result in a healthcare encounter or death, medication dispensation may not reflect medication adherence, residual confounding may have influenced findings, and findings may not be generalizable to persons on opioid therapy in other settings.

CONCLUSIONS

Discontinuing prescribed opioids was associated with increased overdose risk, particularly among people with OUD. Prescribed opioid tapering was associated with reduced overdose risk among people with OUD not receiving OAT. These findings highlight the need to avoid abrupt discontinuation of opioids for pain. Enhanced guidance is needed to support prescribers in implementing opioid therapy tapering strategies with consideration of OUD and OAT status.

Impact of Hepatitis B Virus Infection, Non-alcoholic Fatty Liver Disease, and Hepatitis C Virus Co-infection on Liver-Related Death among People Tested for Hepatitis B Virus in British Columbia: Results from a Large Longitudinal Population-Based Cohort Study

Data on the contribution of hepatitis B virus (HBV) infection and related comorbidities to liver-related mortality in Canada are limited. We assessed the concurrent impact of HBV infection, non-alcoholic fatty liver disease (NAFLD), and hepatitis C virus (HCV) coinfection on liver-related deaths in British Columbia (BC), Canada. We used data from the BC Hepatitis Testers Cohort (BC-HTC). We used Fine-Gray multivariable sub-distributional hazards models to assess the effect of HBV, NAFLD, and HCV coinfection on liver-related mortality, while adjusting for confounders and competing mortality risks. The liver-related mortality rate was higher among people with HBV infection than those without (2.57 per 1000 PYs (95%CI: 2.46, 2.69) vs. 0.62 per 1000 PYs (95%CI: 0.61, 0.64), respectively). Compared with the HBV negative groups, HBV infection was associated with increased liver-related mortality risk in almost all of the subgroups: HBV mono-infection (adjusted subdistribution hazards ratio (asHR) of 3.35, 95% CI 3.16, 3.55), NAFLD with HBV infection, (asHR 12.5, 95% CI 7.08, 22.07), and HBV/HCV coinfection (asHR 8.4, 95% CI 7.62, 9.26). HBV infection is associated with a higher risk of liver-related mortality, and has a greater relative impact on people with NAFLD and those with HCV coinfection. The diagnosis and treatment of viral and fatty liver disease are required to mitigate liver-related morbidity and mortality.

The impact of opioid agonist treatment on hospitalisations for injecting-related diseases among an opioid dependent population: A retrospective data linkage study

BACKGROUND

Injecting-related bacterial and fungal infections cause substantial illness and disability among people who use illicit drugs. Opioid agonist treatment (OAT) reduces injecting frequency and the transmission of blood borne viruses. We estimated the impact of OAT on hospitalisations for non-viral infections and examine trends in incidence over time.

METHODS

We conducted a retrospective cohort study using linked administrative data. The cohort included 47 163 individuals starting OAT between August 2001 and December 2017 in New South Wales, Australia, with 454 951 person-years of follow-up. The primary outcome was hospitalisation for an injecting-related disease. The primary exposure was OAT status (out of OAT, first four weeks of OAT, and OAT retention [i.e., more than four weeks in treatment]). Covariates included demographic characteristics, year of hospitalisation, and recent clinical treatment.

RESULTS

9122 participants (19.3%) had at least one hospitalisation for any injecting-related disease. Compared to time out of treatment, retention on OAT was associated with a reduced rate of injecting-related diseases (adjusted rate ratio[ARR]=0.92; 95%CI 0.87-0.97). The first four weeks of treatment was associated with an increased rate (ARR 1.53, 95%CI 1.38-1.70), which we believe is explained by referral pathways between hospital and community OAT services. The age-adjusted incidence rates of hospitalisations for any injecting-related disease increased from 34.8 (95% CI =30.2-40.0) per 1000 person-years in 2001 to 54.9 (95%CI=51.3-58.8) in 2017.

INTERPRETATION

Stable OAT is associated with reduced hospitalisations for injecting-related bacterial infections; however, OAT appears insufficient to prevent these harms as the rate of these infections is increasing in Australia.

Estimating the causal effect of treatment with direct-acting antivirals on kidney function among individuals with hepatitis C virus infection

Background

Direct-acting antivirals (DAA) are highly effective at treating Hepatitis C virus (HCV) infection, with a cure rate >95%. However, the effect of DAAs on kidney function remains debated.

Methods

We analyzed electronic health record data for DAA-naive patients with chronic HCV infection engaged in HCV care at Boston Medical Center between 2014 and 2018. We compared the following hypothetical interventions using causal inference methods: 1) initiation of DAA and 2) no DAA initiation. For patients with normal kidney function at baseline (eGFR>90 ml/min/1.73m²), we estimated and compared the risk for reaching Stage 3 chronic kidney disease (CKD) (eGFR≤60 ml/min/1.73m²) under each intervention. For patients with baseline CKD Stages 2–4 (15<eGFR≤90 ml/min/1.73m²), we estimated and compared the mean change in eGFR at 2 years after baseline under each intervention. We used the parametric g-formula to adjust our estimates for baseline and time-varying confounders.

Results

First, among 1390 patients with normal kidney function at baseline the estimated 2-year risk difference (95% CI) of reaching Stage 3 CKD for DAA initiation versus no DAA was -1% (-3, 2). Second, among 733 patients with CKD Stage 2–4 at baseline the estimated 2-year mean difference in change in eGFR for DAA initiation versus no DAA therapy was -3 ml/min/1.73m² (-8, 2).

Conclusions

We found no effect of DAA initiation on kidney function, independent of baseline renal status. This suggests that DAAs may not be nephrotoxic; furthermore, in the short-term, HCV clearance may not improve CKD.

Hospitalisation with injection-related infections: Validation of diagnostic codes to monitor admission trends at a tertiary care hospital in Melbourne, Australia

INTRODUCTION

Injection-related infections (IRI) cause morbidity and mortality in people who inject drugs. Hospital administrative datasets can be used to describe hospitalisation trends, but there are no validated algorithms to identify injecting drug use and IRIs. We aimed to validate International Classification of Diseases (ICD) codes to identify admissions with IRIs and use these codes to describe IRIs within our hospital.

METHODS

We developed a candidate set of ICD codes to identify current injecting drug use and IRI and extracted admissions satisfying both criteria. We then used manual chart review data from 1 January 2017 to 30 April 2019 to evaluate the performance of these codes and refine our algorithm by selecting codes with a high-positive predictive value (PPV). We used the refined algorithm to describe trends and outcomes of people who inject drugs with an IRI at Alfred Hospital, Melbourne from 2008 to 2020.

RESULTS

Current injecting drug use was best predicted by opioid-related disorders (F11), 80% (95% confidence interval [CI] 74-85%), and other stimulant-related disorders (F15), 82% (95% CI 70-90%). All PPVs were ≥67% to identify specific IRIs, and ≥84% for identifying any IRI. Using these codes over 12 years, IRIs increased from 138 to 249 per 100 000 admissions, and skin and soft tissues infections (SSTI) were the most common (797/1751, 46%).

DISCUSSION AND CONCLUSION

Validated ICD-based algorithms can inform passive surveillance systems. Strategies to reduce hospitalisation with IRIs should be supported by early intervention and prevention, particularly for SSTIs which may represent delayed access to care.

The Impact of Current Opioid Agonist Therapy on Hepatitis C Virus Treatment Initiation Among People Who Use Drugs From the Direct-acting Antiviral (DAA) Era: A Population-Based Study

BACKGROUND

Evidence that opioid agonist therapy (OAT) is associated with increased odds of hepatitis C virus (HCV) treatment initiation among people who use drugs (PWUD) is emerging. The objective of this study was to determine the association between current OAT and HCV treatment initiation among PWUD in a population-level linked administrative dataset.

METHODS

The British Columbia Hepatitis Testers Cohort was used for this study, which includes all people tested for or diagnosed with HCV in British Columbia, linked to medical visits, hospitalizations, laboratory, prescription drug, and mortality data from 1992 until 2019. PWUD with injecting drug use or opioid use disorder and chronic HCV infection were identified for inclusion in this study. HCV treatment initiation was the main outcome, and subdistribution proportional hazards modeling was used to assess the relationship with current OAT.

RESULTS

In total, 13 803 PWUD with chronic HCV were included in this study. Among those currently on OAT at the end of the study period, 47% (2704/5770) had started HCV treatment, whereas 22% (1778/8033) of those not currently on OAT had started HCV treatment. Among PWUD with chronic HCV infection, current OAT was associated with higher likelihood of HCV treatment initiation in time to event analysis (adjusted hazard ratio 1.84 [95% confidence interval {CI}, 1.50, 2.26]).

CONCLUSIONS

Current OAT was associated with a higher likelihood of HCV treatment initiation. However, many PWUD with HCV currently receiving OAT have yet to receive HCV treatment. Enhanced integration between substance use care and HCV treatment is needed to improve the overall health of PWUD.

Association Between Prescription Opioid Therapy for Noncancer Pain and Hepatitis C Virus Seroconversion

IMPORTANCE

Initiation of injection drug use may be more frequent among people dispensed prescription opioid therapy for noncancer pain, potentially increasing the risk of hepatitis C virus (HCV) acquisition.

OBJECTIVE

To assess the association between medically dispensed long-term prescription opioid therapy for noncancer pain and HCV seroconversion among individuals who were initially injection drug use-naive.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, retrospective cohort study of individuals tested for HCV in British Columbia, Canada, with linkage to outpatient pharmacy dispensations, was conducted. Individuals with an initial HCV-negative test result followed by 1 additional test between January 1, 2000, and December 31, 2017, and who had no history of substance use at baseline (first HCV-negative test), were included. Participants were followed up from baseline to the last HCV-negative test or estimated date of seroconversion (midpoint between HCV-positive and the preceding HCV-negative test).

EXPOSURES

Episodes of prescription opioid use for noncancer pain were defined as acute (<90 days) or long-term (≥90 days). Prescription opioid exposure status (long-term vs prescription opioid-naive/acute) was treated as time-varying in survival analyses. In secondary analyses, long-term exposure was stratified by intensity of use (chronic vs. episodic) and by average daily dose in morphine equivalents (MEQ).

MAIN OUTCOMES AND MEASURES

Multivariable Cox regression models were used to assess the association between time-varying prescription opioid status and HCV seroconversion.

RESULTS

A total of 382 478 individuals who had more than 1 HCV test were included, of whom more than half were female (224 373 [58.7%]), born before 1974 (201 944 [52.8%]), and younger than 35 years at baseline (196 298 [53.9%]). Participants were followed up for 2 057 668 person-years and 1947 HCV seroconversions occurred. Of the participants, 41 755 people (10.9%) were exposed to long-term prescription opioid therapy at baseline or during follow-up. The HCV seroconversion rate per 1000 person-years was 0.8 among the individuals who were prescription opioid-naive/acute (1489 of 1947 [76.5%] seroconversions; 0.4% seroconverted within 5 years) and 2.1 with long-term prescription opioid therapy (458 of 1947 [23.5%] seroconversions; 1.1% seroconverted within 5 years). In multivariable analysis, exposure to long-term prescription opioid therapy was associated with a 3.2-fold (95% CI, 2.9-3.6) higher risk of HCV seroconversion (vs prescription opioid-naive/acute). In separate Cox models, long-term chronic use was associated with a 4.7-fold higher risk of HCV seroconversion (vs naive/acute use 95% CI, 3.9-5.8), and long-term higher-dose use (≥90 MEQ) was associated with a 5.1-fold higher risk (vs naive/acute use 95% CI, 3.7-7.1).

CONCLUSIONS AND RELEVANCE

In this cohort study of people with more than 1 HCV test, long-term prescription opioid therapy for noncancer pain was associated with a higher risk of HCV seroconversion among individuals who were injection drug use-naive at baseline or at prescription opioid initiation. These results suggest injection drug use initiation risk is higher among people dispensed long-term therapy and may be useful for informing approaches to identify and prevent HCV infection. These findings should not be used to justify abrupt discontinuation of long-term therapy, which could increase risk of harms.

Chronic hepatitis C infection is associated with higher incidence of extrahepatic cancers in a Canadian population based cohort

INTRODUCTION

Chronic infection with hepatitis C virus (HCV) is an established risk factor for liver cancer. Although several epidemiologic studies have evaluated the risk of extrahepatic malignancies among people living with HCV, due to various study limitations, results have been heterogeneous.

METHODS

We used data from the British Columbia Hepatitis Testers Cohort (BC-HTC), which includes all individuals tested for HCV in the Province since 1990. We assessed hepatic and extrahepatic cancer incidence using data from BC Cancer Registry. Standardized incidence ratios (SIR) comparing to the general population of BC were calculated for each cancer site from 1990 to 2016.

RESULTS

In total, 56,823 and 1,207,357 individuals tested positive and negative for HCV, respectively. Median age at cancer diagnosis among people with and without HCV infection was 59 (interquartile range (IQR): 53-65) and 63 years (IQR: 54-74), respectively. As compared to people living without HCV, a greater proportion of people living with HCV-infection were men (66.7% vs. 44.7%, P-value <0.0001), had comorbidities (25.0% vs. 16.3%, P-value <0.0001) and were socially deprived (35.9% vs. 25.0%, P-value <0.0001). The SIRs for liver (SIR 33.09; 95% CI 29.80-36.39), anal (SIR: 2.57; 95% CI 1.52-3.63), oesophagus (SIR: 2.00; 95% CI 1.17-2.82), larynx (SIR: 3.24; 95% CI 1.21-5.27), lung (SIR: 2.20; 95% CI 1.82-2.58), and oral (SIR: 1.78; 95% CI 1.33-2.23) cancers were significantly higher among individuals living with HCV. The SIRs for bile duct and pancreatic cancers were significantly elevated among both individuals living with (SIR; 95% CI: 2.20; 1.27-3.14; 2.18; 1.57-2.79, respectively) and without HCV (SIR; 95% CI: 2.12; 1.88-2.36; 1.20; 1.11-1.28, respectively).

DISCUSSION/CONCLUSION

In this study, HCV infection was associated with increased incidence of several extrahepatic cancers. The elevated incidence of multiple cancers among negative HCV testers highlights the potential contributions of screening bias and increased cancer risks associated with factors driving acquisition of infection among this population compared to the general population. Early HCV diagnosis and treatment as well as public health prevention strategies are needed to reduce the risk of extrahepatic cancers among people living with HCV and potentially populations who are at higher risk of HCV infection.

Prescription opioid treatment for non-cancer pain and initiation of injection drug use: large retrospective cohort study

OBJECTIVE

To assess the association between long term prescription opioid treatment medically dispensed for non-cancer pain and the initiation of injection drug use (IDU) among individuals without a history of substance use.

DESIGN

Retrospective cohort study.

SETTING

Large administrative data source (containing information for about 1.7 million individuals tested for hepatitis C virus or HIV in British Columbia, Canada) with linkage to administrative health databases, including dispensations from community pharmacies.

PARTICIPANTS

Individuals age 11-65 years and without a history of substance use (except alcohol) at baseline.

MAIN OUTCOME MEASURES

Episodes of prescription opioid use for non-cancer pain were identified based on drugs dispensed between 2000 and 2015. Episodes were classified by the increasing length and intensity of opioid use (acute (lasting <90 episode days), episodic (lasting ≥90 episode days; with <90 days' drug supply and/or <50% episode intensity), and chronic (lasting ≥90 episode days; with ≥90 days' drug supply and ≥50% episode intensity)). People with a chronic episode were matched 1:1:1:1 on socioeconomic variables to those with episodic or acute episodes and to those who were opioid naive. IDU initiation was identified by a validated administrative algorithm with high specificity. Cox models weighted by inverse probability of treatment weights assessed the association between opioid use category (chronic, episodic, acute, opioid naive) and IDU initiation.

RESULTS

59 804 participants (14 951 people from each opioid use category) were included in the matched cohort, and followed for a median of 5.8 years. 1149 participants initiated IDU. Cumulative probability of IDU initiation at five years was highest for participants with chronic opioid use (4.0%), followed by those with episodic use (1.3%) and acute use (0.7%), and those who were opioid naive (0.4%). In the inverse probability of treatment weighted Cox model, risk of IDU initiation was 8.4 times higher for those with chronic opioid use versus those who were opioid naive (95% confidence interval 6.4 to 10.9). In a sensitivity analysis limited to individuals with a history of chronic pain, cumulative risk for those with chronic use (3.4% within five years) was lower than the primary results, but the relative risk was not (hazard ratio 9.7 (95% confidence interval 6.5 to 14.5)). IDU initiation was more frequent at higher opioid doses and younger ages.

CONCLUSIONS

The rate of IDU initiation among individuals who received chronic prescription opioid treatment for non-cancer pain was infrequent overall (3-4% within five years) but about eight times higher than among opioid naive individuals. These findings could have implications for strategies to prevent IDU initiation, but should not be used as a reason to support involuntary tapering or discontinuation of long term prescription opioid treatment.

Impact of direct-acting antivirals for HCV on mortality in a large population-based cohort study

BACKGROUND & AIMS

We evaluated the effect of direct-acting antiviral (DAA)-induced sustained virologic response (SVR) on all-cause, liver- and drug-related mortality in a population-based cohort in British Columbia, Canada.

METHODS

We used data from the British Columbia Hepatitis Testers Cohort, which includes people tested for HCV since 1990, linked with data on medical visits, hospitalizations, prescription drugs and mortality. We followed people who received DAAs and people who did not receive any HCV treatment to death or December 31, 2019. We used inverse probability of treatment weighting to balance the baseline profile of treated and untreated individuals and performed multivariable proportional hazard modelling to assess the effect of DAAs on mortality.

RESULTS

Our cohort comprised 10,851 people treated with DAAs (SVR 10,426 [96%], no-SVR: 425) and 10,851 matched untreated individuals. Median follow-up time was 2.2 years (IQR 1.3-3.6; maximum 6.2). The all-cause mortality rate was 19.5/1,000 person-years (PY) among the SVR group (deaths = 552), 86.5/1,000 PY among the no-SVR group (deaths = 96), and 99.2/1,000 PY among the untreated group (deaths = 2,133). In the multivariable model, SVR was associated with significant reduction in all-cause (adjusted hazard ratio [aHR] 0.19; 95% CI 0.17-0.21), liver- (adjusted subdistribution HR [asHR] 0.22, 95% CI 0.18-0.27) and drug-related mortality (asHR 0.26, 95% CI 0.21-0.32) compared to no-treatment. Older age and cirrhosis were associated with higher risk of liver-related mortality while younger age, injection drug use (IDU), problematic alcohol use and HIV/HBV co-infections were associated with a higher risk of drug-related mortality.

CONCLUSIONS

DAA treatment is associated with a substantial reduction in all-cause, liver- and drug-related mortality. The association of IDU and related syndemic factors with a higher risk of drug-related mortality calls for an integrated social support, addiction, and HCV care approach among people who inject drugs.

LAY SUMMARY

We assessed the effect of treatment of hepatitis C virus infection with direct-acting antiviral drugs on deaths from all causes, liver disease and drug use. We found that treatment with direct-acting antiviral drugs is associated with substantial lowering in risk of death from all causes, liver disease and drug use among people with hepatitis C virus infection.

Mental Health and Substance Use Associated with Hospitalization among People with COVID-19: A Population-Based Cohort Study

This study identified factors associated with hospital admission among people with laboratory-diagnosed COVID-19 cases in British Columbia. The study used data from the BC COVID-19 Cohort, which integrates data on all COVID-19 cases with data on hospitalizations, medical visits, emergency room visits, prescription drugs, chronic conditions and deaths. The analysis included all laboratory-diagnosed COVID-19 cases in British Columbia to 15 January 2021. We evaluated factors associated with hospital admission using multivariable Poisson regression analysis with robust error variance. Of the 56,874 COVID-19 cases included in the analysis, 2298 were hospitalized. Factors associated with increased hospitalization risk were as follows: male sex (adjusted risk ratio (aRR) = 1.27; 95% CI = 1.17–1.37), older age (p-trend < 0.0001 across age groups increasing hospitalization risk with increasing age [aRR 30–39 years = 3.06; 95% CI = 2.32–4.03, to aRR 80+ years = 43.68; 95% CI = 33.41–57.10 compared to 20–29 years-old]), asthma (aRR = 1.15; 95% CI = 1.04–1.26), cancer (aRR = 1.19; 95% CI = 1.09–1.29), chronic kidney disease (aRR = 1.32; 95% CI = 1.19–1.47), diabetes (treated without insulin aRR = 1.13; 95% CI = 1.03–1.25, requiring insulin aRR = 5.05; 95% CI = 4.43–5.76), hypertension (aRR = 1.19; 95% CI = 1.08–1.31), injection drug use (aRR = 2.51; 95% CI = 2.14–2.95), intellectual and developmental disabilities (aRR = 1.67; 95% CI = 1.05–2.66), problematic alcohol use (aRR = 1.63; 95% CI = 1.43–1.85), immunosuppression (aRR = 1.29; 95% CI = 1.09–1.53), and schizophrenia and psychotic disorders (aRR = 1.49; 95% CI = 1.23–1.82). In an analysis restricted to women of reproductive age, pregnancy (aRR = 2.69; 95% CI = 1.42–5.07) was associated with increased risk of hospital admission. Older age, male sex, substance use, intellectual and developmental disability, chronic comorbidities, and pregnancy increase the risk of COVID-19-related hospitalization.

Evaluating Montréal's harm reduction interventions for people who inject drugs: protocol for observational study and cost-effectiveness analysis

INTRODUCTION

The main harm reduction interventions for people who inject drugs (PWID) are supervised injection facilities, needle and syringe programmes and opioid agonist treatment. Current evidence supporting their implementation and operation underestimates their usefulness by excluding skin, soft tissue and vascular infections (SSTVIs) and anoxic/toxicity-related brain injury from cost-effectiveness analyses (CEA). Our goal is to conduct a comprehensive CEA of harm reduction interventions in a setting with a large, dispersed, heterogeneous population of PWID, and include prevention of SSTVIs and anoxic/toxicity-related brain injury as measures of benefit in addition to HIV, hepatitis C and overdose morbidity and mortalities averted.

METHODS AND ANALYSIS

This protocol describes how we will develop an open, retrospective cohort of adult PWID living in Québec between 1 January 2009 and 31 December 2020 using administrative health record data. By complementing this data with non-linkable paramedic dispatch records, regional monthly needle and syringe dispensation counts and repeated cross-sectional biobehavioural surveys, we will estimate the hazards of occurrence and the impact of Montréal's harm reduction interventions on the incidence of drug-use-related injuries, infections and deaths. We will synthesise results from our empirical analyses with published evidence to simulate infections and injuries in a hypothetical population of PWID in Montréal under different intervention scenarios including current levels of use and scale-up, and assess the cost-effectiveness of each intervention from the public healthcare payer's perspective.

ETHICS AND DISSEMINATION

This study was approved by McGill University's Institutional Review Board (Study Number: A08-E53-19B). We will work with community partners to disseminate results to the public and scientific community via scientific conferences, a publicly accessible report, op-ed articles and open access peer-reviewed journals.

Health care utilization and costs associated with direct-acting antivirals for patients with substance use disorders and chronic hepatitis C

BACKGROUND: Patients with substance use disorders (SUD) and chronic hepatitis C virus infection (HCV) have limited access to direct-acting antivirals (DAAs) due to multilevel issues related to providers (eg, concern about reinfection); patients (eg, refusal); payers (eg, prior authorization); and health system structure, although clinical guidelines recommend timely DAA treatment for patients with SUD and HCV. Effects of DAAs on real-world health care utilization and costs among these patients is unknown. OBJECTIVE: To compare changes in medical service utilization and costs related to liver, SUD, and all-cause morbidity in patients with SUD and HCV treated with DAAs (DAA group) vs not treated with DAAs (non-DAA group). METHODS: We conducted a retrospective cohort study using MarketScan Commercial and Medicare Supplemental Claims databases (2012-2018) for newly diagnosed HCV treatment-naive adults with SUD. We used difference-in-differences analyses, stratified by cirrhosis status, to determine the adjusted ratio of rate ratio (RoRR) to assess the difference in the relative changes from the pre- to posttreatment periods between the 2 groups. RESULTS: 6,266 patients with SUD and HCV were identified. Of these patients who also had cirrhosis (n = 607), 49% (n = 298) initiated DAA therapy for HCV, whereas of those without cirrhosis (n = 5,659), 22% (n = 1,219) initiated DAAs. For patients with cirrhosis (n = 607), the liver-related costs decreased by $6,213 (95% CI = -$8,571, -$3,856) for the DAA group and $1,585 (95% CI = -$4,659, $1,490) for the non-DAA group. The relative decreases in the rate of liver-related costs were larger for the DAA group than for the non-DAA group, and the relative changes between groups were significantly different (RoRR = 0.37, 95% CI = 0.19-0.73). There was no difference in the relative changes after DAAs in the rate of SUD-related visits/costs or all-cause costs between the 2 groups. For patients without cirrhosis (n = 5,659), a similar association was observed. Besides, the relative decreases in the rate of SUD-related emergency department (ED) visits (RoRR = 0.54, 95% CI = 0.38-0.77); SUD-related long-term care visits (RoRR = 0.30, 95% CI = 0.13-0.73); all-cause ED visits (RoRR = 0.75, 95% CI = 0.64-0.88); and all-cause long term-care visits (RoRR = 0.36, 95% CI = 0.18-0.72) were larger in the DAA group than in the non-DAA group. CONCLUSIONS: DAAs are associated with a significant decrease in the rate of SUD-related ED visits and liver-related costs without increasing the rate of all-cause costs among patients with SUD and HCV, suggesting that the benefits of DAAs extended beyond liver-related outcomes, especially in this disadvantaged population. DISCLOSURES: Research reported in this publication was supported in part by the National Institute on Drug Abuse of the National Institutes of Health (K01DA045618). The funder did not have a role in the design, the execution, the analyses, the interpretation of the data, or the decision to submit the results of this study. The authors have no potential conflicts of interest.

Cascade of Hepatitis C Virus Care Among Patients With Substance Use Disorders

INTRODUCTION

Hepatitis C virus testing is recommended for people at high risk for infection, including those with substance use disorders. Little is known about the cascade of hepatitis C virus care (including testing, diagnosis, and treatments) among patients with substance use disorders in real-world clinical practice. This study aims to characterize the hepatitis C virus cascade of care and identify the factors associated with hepatitis C virus testing and diagnosis among Florida Medicaid beneficiaries with substance use disorders.

METHODS

A retrospective cohort analysis of Florida Medicaid data (2013-2018) was conducted in 2020 for patients aged 18-64 years with newly diagnosed substance use disorders (year 2012 was used to ascertain 1-year previous enrollment). A generalized estimating equation identified the factors associated with hepatitis C virus testing; a multivariable logistic model identified the factors associated with hepatitis C virus diagnosis.

RESULTS

Of the 156,770 patients with substance use disorders, 18% were tested for hepatitis C virus at least once. Among the tested patients, 8% had hepatitis C virus diagnoses. Among the 2,177 patients having a hepatitis C virus diagnosis, 11% initiated hepatitis C virus treatments, and 96% of them completed the hepatitis C virus treatments. Factors associated with being less likely to receive hepatitis C virus testing included being male (AOR=0.73, 95% CI=0.71, 0.75) and White (AOR=0.85, 95% CI=0.83, 0.87), whereas individuals who were male (AOR=1.49, 95% CI=1.35, 1.66) and White (AOR=2.71, 95% CI=2.38, 3.08) were more likely to be diagnosed with hepatitis C virus. The odds of receiving hepatitis C virus testing significantly increased annually (AOR=1.06, 95% CI=1.05, 1.07).

CONCLUSIONS

Future studies are warranted to investigate the barriers to access hepatitis C virus testing and treatment among Florida Medicaid beneficiaries with substance use disorders, especially for White male individuals.

Syringe services programs in the Bluegrass: Evidence of population health benefits using Kentucky Medicaid data

PURPOSE

To evaluate whether Kentucky counties that established a new syringe services program realized a significant decline in the incidence rate of a set of infectious disease diagnoses commonly transmitted via injection drug use.

METHODS

Longitudinal count models of within-county rates of newly diagnosed infections among populations at risk were estimated using Medicaid claims/encounters data. Generalized estimating equation models were used to report incident rate ratios of 6 diagnoses: (1) HIV; (2) hepatitis C; (3) hepatitis B; (4) osteomyelitis; (5) endocarditis; and (6) skin/soft tissue infection. To investigate whether a delay in effect was present, separate models were fit to estimate the effects of establishing a syringe services program: at its opening date, and again at 1, 3, and 6 months postopening date.

FINDINGS

Taken together, the aggregated within-county incidence rate of these 6 diagnoses was significantly lower following the implementation of a syringe services program (P < .05). Our models estimated that counties which opted to open a syringe services program realized an approximate month-over-month decline in new diagnoses of 0.5% among the population at risk.

CONCLUSIONS

These results lend further support to previous conclusions made in the public health literature regarding the efficacy of syringe services programs. Specifically, declines in incidence rates were observable beginning at 1 month post syringe services program opening. These results are particularly notable due to the typical setting in which these syringe services programs operated-rural communities of fewer than 40,000 residents.

Hepatitis C Treatment by Nonspecialist Providers in the Direct-acting Antiviral Era

BACKGROUND

Hepatitis C virus (HCV) remains under-treated in the United States and treatment by nonspecialist providers can expand access. We compare HCV treatment provision and treatment completion between nonspecialist and specialist providers.

METHODS

This retrospective study used claims data from the Healthcare Cost Institute from 2013 to 2017. We identified providers who prescribed HCV therapy between 2013 and 2017, and patients enrolled in private insurance or Medicare Advantage who had pharmacy claims for HCV treatment. We measured HCV treatment completion, determined based on prescription fills for the minimum expected duration of the antiviral regimen. Using propensity score-weighted regression, we compared the likelihood of early treatment discontinuation by the type of treating provider.

RESULTS

The number of providers prescribing HCV treatment peaked in 2015 and then declined. The majority were gastroenterologists, although the proportion of general medicine providers increased to 17% by 2017. Among the 23,463 patients analyzed, 1008 (4%) discontinued before the expected minimum duration. In the propensity score-weighted analysis, patients treated by general medicine physicians had similar odds of treatment discontinuation compared with those treated by gastroenterologists [odds ratio (OR)=1.00, 95% confidence interval (CI): 0.99-1.01, P=0.45]. Results were similar when comparing gastroenterologists to nonphysician providers (OR=1.00, 95% CI: 0.99-1.01, P=0.53) and infectious diseases specialists (OR=1.00, 95% CI: 0.99-1.01, P=0.71).

CONCLUSIONS

HCV treatment providers remain primarily gastroenterologists, even in the current simplified treatment era. Patients receiving treatment from general medicine or nonphysician providers had a similar likelihood of treatment completion, suggesting that removing barriers to the scale-up of treatment by nonspecialists may help close treatment gaps for hepatitis C.

The Impact of Direct-Acting Antiviral Therapy on End-Stage Liver Disease Among Individuals with Chronic Hepatitis C and Substance Use Disorders

BACKGROUND AND AIMS

Our aim was to evaluate the impact of direct-acting antivirals (DAAs) on decompensated cirrhosis (DCC) and HCC in patients with chronic HCV and substance use disorder (SUD) compared with those without an SUD.

APPROACH AND RESULTS

This retrospective cohort study used the MarketScan database (2013-2018) to identify 29,228 patients with chronic HCV, where 22% (n = 6,385) had ≥1 SUD diagnosis. The inverse probability of treatment weighted multivariable Cox proportional hazard models were used to compare the risk of developing DCC and HCC. Among the those who were noncirrhotic, treatment reduced the DCC risk among SUD (adjusted hazard ratio [aHR] 0.13; 95% CI, 0.06-0.30) and non-SUD (aHR 0.11; 95% CI, 0.07-0.18), whereas the risk for HCC was not reduced for the SUD group (aHR 0.91; 95% CI, 0.33-2.48). For those with cirrhosis, compared with patients who were untreated, treatment reduced the HCC risk among SUD (aHR, 0.33; 95% CI, 0.13-0.88) and non-SUD (aHR, 0.40; 95% CI, 0.25-0.65), whereas the risk for DCC was not reduced for the SUD group (aHR, 0.64; 95% CI, 0.37-1.13). Among patients with cirrhosis who were untreated, the SUD group had a higher risk of DCC (aHR, 1.52; 95% CI, 1.03-2.24) and HCC (aHR, 1.69; 95% CI, 1.05-2.72) compared with non-SUD group.

CONCLUSIONS

Among the HCV SUD group, DAA treatment reduced the risk of DCC but not HCC for those who were noncirrhotic, whereas DAA treatment reduced the risk of HCC but not DCC for those with cirrhosis. Among the nontreated, patients with an SUD had a significantly higher risk of DCC and HCC compared with those without an SUD. Thus, DAA treatment should be considered for all patients with HCV and an SUD while also addressing the SUD.

The use of all-oral direct-acting antivirals in hepatitis C virus-infected patients with substance use disorders

BACKGROUND: There is evidence that barriers exist for the initiation of direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) for those with substance use disorders (SUDs). However, real world clinical evidence of DAA treatment initiation following receipt of a prescription and continuation among those with SUDs and HCV is lacking. OBJECTIVES: To (1) compare HCV treatment initiation (prescription fill) rates and early discontinuation rates between HCV-infected patients with and without SUDs in the DAA era, and (2) identify patient-level factors associated with HCV treatment initiation and early discontinuation in patients with SUDs. METHODS: A retrospective cohort analysis of the MarketScan databases (January 2012-December 2018) was conducted for newly diagnosed treatment naïve HCV-infected patients (age ≥ 18) with and without SUDs. We used multivariable Cox regression to estimate adjusted hazard ratios (aHRs) with 95% confidence intervals of treatment initiation and early discontinuation in those with SUDs versus those without. RESULTS: We identified a total of 29,228 newly diagnosed HCV-infected patients (6,385 with SUDs and 22,843 without SUDs). Overall, DAA treatment initiation for patients with SUDs was significantly lower than that for those without SUDs (24% vs 34%; P < 0.01). After adjusting for demographics and clinical characteristics, patients with SUDs were less likely to initiate DAA treatments than those without SUDs (aHR, 0.87 [0.82-0.92]). There was no difference in discontinuation of DAA treatment between those with and without SUDs (4% vs 3%: aHR, 1.13 [0.81-1.60]). Among patients with SUDs (n = 6,385), lower rates of initiating DAA treatment was associated with younger age, and comorbidities including alcoholic liver disease (ALD; aHR, 0.44 [0.33-0.57), chronic kidney disease (CKD) (aHR, 0.52 [0.36-0.75]), and hepatitis B virus (HBV; aHR, 0.64 [0.44-0.92]). DAA treatment discontinuation was associated with younger age, ribavirin (RBV) therapy (aHR, 3.78 [2.21-6.47]), and cirrhosis diagnosis (aHR, 2.42 [1.21-4.84]) but not SUD treatment (aHR, 0.68 [0.34-1.34]). CONCLUSIONS: HCV-infected patients with SUDs had significantly lower treatment initiation rates, especially in young females and those with ALD, CKD, and HBV. No difference was found in DAA discontinuation. However, younger patients with RBV treatment and/or cirrhosis were more likely to stop treatment. Interventions directed towards these groups are needed to enhance DAA initiation and treatment maintenance among HCV-infected patients with SUDs. DISCLOSURES: Research reported in this publication was supported in part by the National Institute on Drug Abuse of the National Institutes of Health under award number K01DA045618 (to Park). The other authors have nothing to disclose that may present a potential conflict of interest.

A missed opportunity: underutilization of inpatient behavioral health services to reduce injection drug use sequelae in Florida

Background

People who inject drugs (PWID) suffer high morbidity and mortality from injection related infections (IRI). The inpatient setting is an ideal opportunity to treat underlying substance use disorder (SUD), but it is unclear how often this occurs.

Objectives

To quantify the utilization of behavioral health services for PWID during inpatient admissions for IRI.

Methods

Data for all hospital admissions in Florida in FY2017 were obtained from the Agency for Healthcare Administration. Hospitalization for IRI were obtained using a validated ICD-10 algorithm and treatment for substance use disorder was quantified using ICD-10-Procedure Coding System (ICD-10-PCS) codes.

Result

Among the 20,001 IRI admissions, there were 230 patients who received behavioral health services as defined by ICD-10-PCS SAT codes for treatment for SUD.

Conclusions

In a state with a large number of IRI, only a very small portion of admissions received behavioral health services. Increased efforts should be directed to studying referral patterns among physicians and other providers caring for this population and increasing utilization of behavioral health services.

Incidence of diabetes mellitus among people living with and without HIV in British Columbia, Canada between 2001 and 2013: a longitudinal population-based cohort study

INTRODUCTION

People living with HIV (PLHIV) are increasingly at risk of age-related comorbidities such as diabetes mellitus (DM). While DM is associated with elevated mortality and morbidity, understanding of DM among PLHIV is limited. We assessed the incidence of DM among people living with and without HIV in British Columbia (BC), Canada, during 2001-2013.

METHODS

We used longitudinal data from a population-based cohort study linking clinical data and administrative health data. We included PLHIV who were antiretroviral therapy (ART) naïve at baseline, and 1:5 age-sex-matched persons without HIV. All participants had ≥5 years of historic data pre-baseline and ≥1 year(s) of follow-up. DM was identified using the BC Ministry of Health's definitions applied to hospitalisation, physician billing and drug dispensation datasets. Incident DM was identified using a 5-year run-in period. In addition to unadjusted incidence rates (IRs), we estimated adjusted incidence rate ratios (IRR) using Poisson regression and assessed annual trends in DM IRs per 1000 person years (PYs) between 2001 and 2013.

RESULTS

A total of 129 PLHIV and 636 individuals without HIV developed DM over 17 529 PYs and 88,672 PYs, respectively. The unadjusted IRs of DM per 1000 PYs were 7.4 (95% CI 6.2 to 8.8) among PLHIV and 7.2 (95% CI 6.6 to 7.8) for individuals without HIV. After adjustment for confounding, HIV serostatus was not associated with DM incidence (adjusted IRR: 1.03, 95% CI 0.83 to 1.27). DM incidence did not increase over time among PLHIV (Kendall trend test: p=0.9369), but it increased among persons without HIV between 2001 and 2013 (p=0.0136).

CONCLUSIONS

After adjustment, HIV serostatus was not associated with incidence of DM, between 2001 and 2013. Future studies should investigate the impact of ART on mitigating the potential risk of DM among PLHIV.

Association between discharges against medical advice and readmission in patients treated for drug injection-related skin and soft tissue infections

BACKGROUND

The prevalence of injection drug use (IDU)-related skin and soft tissue infections (SSTI) in Philadelphia has been steadily increasing since 2013. Patients seeking treatment for these infections are more likely to be discharged against medical advice (AMA), increasing the likelihood that they will end antibiotic treatment prematurely and require additional medical interventions.

METHODS

The research team performed a nested case-control study using the Pennsylvania Health Care Cost Containment Council database for Philadelphia residents hospitalized for SSTI and substance use-related diagnoses between 2013 and 2018. The primary outcome was readmission in the same or following quarter. The study examined the impact of discharge AMA on readmission along with clinical characteristics including diagnoses for anxiety, bipolar disorder, depression, schizophrenia, diabetes, and polydrug use.

RESULTS

There were 8265 hospitalizations for IDU-related SSTI and 316 (6%) were readmitted to the hospital at least once in the same or following quarter. In total, 23.4% of cases and 13% of controls left AMA. In the final multivariable regression model, AMA discharge (AOR 2.04, 95% CI 1.46-2.86), anxiety (AOR 1.44, 95% CI 1.01-2.05), diabetes (AOR 2.02, 95% CI 1.46-2.81), and polydrug use (AOR 2.11, 95% CI 1.52-2.92) were associated with higher odds of readmission.

CONCLUSIONS

Our study demonstrates that readmissions for IDU-related SSTI are associated with recent discharge AMA. As IDU-related SSTI and polydrug use continue to rise, premature antibiotic treatment completion will impact more people, leading to worse health outcomes and additional strain on the health care system.

Hospital Costs of Injection Drug Use in Florida

People who inject drugs (PWID) experience significant injection-related infections (IRIs) at significant healthcare system cost. This study used and validated an algorithm based on the International Classification of Diseases, Tenth Revision, to estimate hospitalized PWID populations, assess the total statewide morbidity for IRIs among PWID, and calculate associated costs of care.

Cohort profile: development and characteristics of a retrospective cohort of individuals dispensed prescription opioids for non-cancer pain in British Columbia, Canada

PURPOSE

Prescription opioids (POs) are widely prescribed for chronic non-cancer pain but are associated with several risks and limited long-term benefit. Large, linked data sources are needed to monitor their harmful effects. We developed and characterised a retrospective cohort of people dispensed POs.

PARTICIPANTS

We used a large linked administrative database to create the Opioid Prescribing Evaluation and Research Activities cohort of individuals dispensed POs for non-cancer pain in British Columbia (BC), Canada (1996-2015). We created definitions to categorise episodes of PO use based on a review of the literature (acute, episodic, chronic), developed an algorithm for inferring clinical indication and assessed patterns of PO use across a range of characteristics.

FINDINGS TO DATE

The current cohort includes 1.1 million individuals and 3.4 million PO episodes (estimated to capture 40%-50% of PO use in BC). The majority of episodes were acute (81%), with most prescribed for dental or surgical pain. Chronic use made up 3% of episodes but 88% of morphine equivalents (MEQ). Across the acute to episodic to chronic episode gradient, there was an increasing prevalence of higher potency POs (hydromorphone, oxycodone, fentanyl, morphine), long-acting formulations and chronic pain related indications (eg, back, neck, joint pain). Average daily dose (MEQ) was similar for acute/episodic but higher for chronic episodes. Approximately 7% of the cohort had a chronic episode and chronic pain was the characteristic most strongly associated with chronic PO use. Individuals initiating a chronic episode were also more likely to have higher social/material deprivation and previous experience with a mental health condition or a problem related to alcohol or opioid use. Overall, these findings suggest our episode definitions have face validity and also provide insight into characteristics of people initiating chronic PO therapy.

FUTURE PLANS

The cohort will be refreshed every 2 years. Future analyses will explore the association between POs and adverse outcomes.

HCV reinfection rates after cure or spontaneous clearance among HIV-infected and uninfected men who have sex with men

BACKGROUND & AIMS

Hepatitis C virus (HCV) reinfection among high-risk groups threatens HCV elimination goals. We assessed HCV reinfection rates among men who have sex with men (MSM) in British Columbia (BC), Canada.

METHODS

We used data from the BC Hepatitis Testers Cohort, which includes nearly 1.7 million individuals tested for HCV or HIV in BC. MSM who had either achieved sustained virologic response (SVR) after successful HCV treatment, or spontaneous clearance (SC) and had ≥1 subsequent HCV RNA measurement, were followed from the date of SVR or SC until the earliest of reinfection, death, or last HCV RNA measurement. Predictors of reinfection were identified by Cox proportional modelling. The earliest study start date was 6 November 1997 and latest end date was 13 April 2018.

RESULTS

Of 1349 HCV-positive MSM who met the inclusion criteria, 493 had SC while 856 achieved SVR. 349 (25.65%) had HIV coinfection. We identified 98 reinfections during 5203 person-years (PYs) yielding a reinfection rate of 1.88/100PYs. The reinfection rate among SC (2.74/100PYs) was more than twice that of those with SVR (1.03/100 PYs). Problematic alcohol use (aHR 1.73, 95% CI 1.003-2.92), injection drug use (aHR 2.60, 95% CI 1.57-4.29) and HIV coinfection (aHR 2.04, 95% CI 1.29-3.23) were associated with increased risk of HCV reinfection. Mental health counselling history (aHR 0.24, 95% CI 0.13-0.46) was associated with reduced HCV reinfection risk.

CONCLUSIONS

There is the need to engage MSM in harm reduction and prevention services following treatment to reduce reinfection risk.

Illicit synthetic opioid consumption in Asia and the Pacific: Assessing the risks of a potential outbreak

BACKGROUND

Illegally manufactured potent synthetic opioids (IMPSO) like fentanyl have contributed to rises in overdose deaths in parts of North America and Europe. While many of these substances are produced in Asia, there is little evidence they have entered markets there. We consider the susceptibility to IMPSO's encroachment in markets in the Asia-Pacific region.

METHODS

Our analysis focuses on Australia, China, India, and Myanmar. Using a mixed-methods approach comprising interviews, literature review, and secondary data analyses, we examine factors facilitating or impeding incursion of IMPSO. Finally, we illustrate the potential for IMPSO fatalities in Australia.

RESULTS

Australia reports some signs of three facilitating factors to IMPSO's emergence: 1) existing illicit opioid markets, 2) disruption of opioid supply, and 3) user preferences. The other three countries report only existing illicit opioid markets. While diverted pharmaceutical opioids are a noted problem in Australia and India, heroin is the dominant opioid in all four countries. There are divergent trends in heroin use, with use declining in China, increasing in India, and stable in Australia and Myanmar. If IMPSO diffused in Australia as in North America from 2014 to 2018, and our assumptions generally hold, deaths from IMPSO could range from 1500-5700 over a five-year period.

CONCLUSIONS

This analysis and illustrative calculations serve as an early indication for policymakers. With the exception of Australia, many countries in the region fail to properly record overdose deaths or monitor changes in local drug markets. Early assessment and monitoring can give officials a better understanding of these changing threats.

Elevated risk of colorectal, liver, and pancreatic cancers among HCV, HBV and/or HIV (co)infected individuals in a population based cohort in Canada

Introduction:

Studies of the impact of hepatitis C virus (HCV), hepatitis B virus (HBV) and HIV mono and co-infections on the risk of cancer, particularly extra-hepatic cancer, have been limited and inconsistent in their findings.

Methods:

In the British Columbia Hepatitis Testers Cohort, we assessed the risk of colorectal, liver, and pancreatic cancers in association with HCV, HBV and HIV infection status. Using Fine and Gray adjusted proportional subdistribution hazards models, we assessed the impact of infection status on each cancer, accounting for competing mortality risk. Cancer occurrence was ascertained from the BC Cancer Registry.

Results:

Among 658,697 individuals tested for the occurrence of all three infections, 1407 colorectal, 1294 liver, and 489 pancreatic cancers were identified. Compared to uninfected individuals, the risk of colorectal cancer was significantly elevated among those with HCV (Hazard ration [HR] 2.99; 95% confidence interval [CI] 2.55–3.51), HBV (HR 2.47; 95% CI 1.85–3.28), and HIV mono-infection (HR 2.30; 95% CI 1.47–3.59), and HCV/HIV co-infection. The risk of liver cancer was significantly elevated among HCV and HBV mono-infected and all co-infected individuals. The risk of pancreatic cancer was significantly elevated among individuals with HCV (HR 2.79; 95% CI 2.01–3.70) and HIV mono-infection (HR 2.82; 95% CI 1.39–5.71), and HCV/HBV co-infection.

Discussion/Conclusion:

Compared to uninfected individuals, the risk of colorectal, pancreatic and liver cancers was elevated among those with HCV, HBV and/or HIV infection. These findings highlight the need for targeted cancer prevention and diligent clinical monitoring for hepatic and extrahepatic cancers in infected populations.

Estimates of people who injected drugs within the last 12 months in Belgium based on a capture-recapture and multiplier method

BACKGROUND

For Belgium, available estimates of the number of people who inject drugs (PWID) are based on data from more than fifteen years ago and apply only to those who report ever injecting drugs. As a result, no reliable baseline data exist to determine the scale of services for PWID.

METHODS

We obtained pseudo-anonymized identifier information from treatment and harm reduction service providers and a fieldwork study between February and April 2019 in Brussels. We estimated the number of PWID, defined as people who injected within the last 12 months, in Brussels using capture-recapture (CRC) methodology. To obtain national estimates, we scaled the proportion of PWID in Brussels to the total number of this population in Belgium based on two existing drug treatment registers, which were then multiplied with the result of the CRC.

RESULTS

The total population of PWID is estimated to be 703 (95 %CI 538-935) for Brussels and between 6620 (95 %CI 4711 - 8576) and 7018 (95 %CI 4794 - 9527) for Belgium.

CONCLUSIONS

These estimates provide crucial information to ensure that services to PWID are adequately maintained. They clearly indicate the need to maximize efforts to achieve the targets set by WHO for 2030 on the provision of 300 sterile needles and syringes per PWID per year, a 90 % reduction of new HCV infections, and a 65 % reduction of liver-related mortality.

High hepatitis C treatment uptake among people with recent drug dependence in New South Wales, Australia

BACKGROUND & AIMS

High HCV treatment uptake among people at most risk of transmission is essential to achieve elimination. We aimed to characterise subpopulations of people with HCV based on drug dependence, to estimate direct-acting antiviral (DAA) uptake in an unrestricted treatment era, and to evaluate factors associated with treatment uptake among people with recent drug dependence.

METHODS

HCV notifications in New South Wales, Australia (1995-2017) were linked to opioid agonist therapy (OAT), hospitalisations, incarcerations, HIV notifications, deaths, and prescription databases. Drug dependence was defined as hospitalisation due to injectable drugs or receipt of OAT, with indicators in 2016-2018 considered recent. Records were weighted to account for spontaneous clearance. Logistic regression was used to analyse factors associated with treatment uptake among those with recent drug dependence.

RESULTS

57,467 people were estimated to have chronic HCV throughout the DAA era. Treatment uptake was highest among those with recent (47%), compared to those with distant (38%), and no (33%) drug dependence. Among those with recent drug dependence, treatment was more likely among those with HIV (adjusted odds ratio [aOR] 1.71; 95% CI 1.24-2.36), recent incarceration (aOR 1.10; 95% CI 1.01-1.19), and history of alcohol use disorder (aOR 1.22; 95% CI 1.13-1.31). Treatment was less likely among women (aOR 0.78; 95% CI 0.72-0.84), patients of Indigenous ethnicity (aOR 0.75; 95% CI 0.69-0.81), foreign-born individuals (aOR 0.86; 95% CI 0.78-0.96), those with outer-metropolitan notifications (aOR 0.90; 95% CI 0.82-0.98), HBV coinfection (aOR 0.69; 95% CI 0.59-0.80), and >1 recent hospitalisation (aOR: 0.91; 95% CI 0.84-0.98).

CONCLUSIONS

These data provide evidence of high DAA uptake among people with recent drug dependence, including those who are incarcerated. Enhancing this encouraging initial uptake among high-risk populations will be essential to achieve HCV elimination.

LAY SUMMARY

To facilitate HCV elimination, those at highest risk of infection and transmission are a treatment priority. This study shows the successes of Australia's universal provision of DAA therapy in reducing the barriers to treatment which have historically persisted among people who inject drugs. Despite higher DAA therapy uptake among those with recent drug dependence, gaps remain. Strategies which aim to reduce marginalisation and increase treatment uptake to ensure equitable HCV elimination must be advanced.

Changes in Infective Endocarditis Admissions in Pennsylvania During the Opioid Epidemic

BACKGROUND

With the current opioid crisis in the United States, infectious complications related to injection drug use are increasingly reported. Pennsylvania is at the epicenter of the opioid crisis, with the third highest rate of drug overdose deaths in the United States.

METHODS

A retrospective cohort study was performed using the Pennsylvania Health Care Cost Containment Council database of all residents hospitalized for infective endocarditis (IE) in an acute care hospital from 1 January 2013 through 31 March 2017. Patients were separated into those with and those without substance use via diagnosis codes. The primary outcome was length of stay. Secondarily, we evaluated demographics, infection history, hospital charges, and insurance status.

RESULTS

Of the 17 224 hospitalizations, 1921 (11.1%) were in patients with drug use-associated IE (DU-IE). Total quarterly IE admissions increased 20%, with a 6.5% increase in non-drug use-associated IE (non-DU-IE) admissions and a 238% increase in DU-IE admissions. In adjusted models, DU-IE was not associated with significant changes in length of stay (incidence rate ratio, 1.02; 95% confidence interval, .975-1.072; P = .36). Patients with DU-IE were predominantly insured by Medicaid (68.3% vs 13.4% for non-DU-IE), they had higher hospital charges ($86 622 vs $66 802), and they were more likely to leave against medical advice (15.7% vs 1.1%) (all P < .001).

CONCLUSIONS

Our study demonstrates an increase in IE admissions, driven by an increase in admissions for DU-IE. The higher charges, proportion of patients on Medicaid, and rates of leaving against medical advice among the DU-IE group shows the downstream effects of the opioid crisis.

Drug-related deaths in a population-level cohort of people living with and without hepatitis C virus in British Columbia, Canada

BACKGROUND

The majority of new HCV infections in Canada occur in people who inject drugs. Thus, while curative direct antiviral agents (DAAs) herald a promising new era in hepatitis C virus (HCV) treatment, improving the lives and wellbeing of people living with HCV (PLHCV) must be considered in the context of reducing overdose-related harms and with a syndemic lens. We measure drug-related deaths (DRDs) among HCV-negative people and PLHCV in British Columbia (BC), Canada, and the impact of potent contaminants like fentanyl on deaths.

METHODS

We identified DRDs among PLHCV and HCV-negative individuals from 2010 to 2018 in the BC Hepatitis Testers Cohort, a population-based dataset of ~1.7 million British Columbians comprising comprehensive administrative and clinical data. We estimated annual standardized liver- and drug-related mortality rates per 100,000 person-years (PY) and described the contribution of specific drugs, including fentanyl and its analogues, implicated in DRDs over time.

RESULTS

DRDs constituted 20.1% of deaths among PLHCV and 4.7% of deaths among HCV-negative individuals; a 4.3-fold (95% confidence interval: 4.0-4.5) difference. Drug-related mortality overtook liver-related mortality for PLHCV in 2015 and HCV-negative individuals in 2016 and rose from 241.7 to 436.5 per 100,000 PY from 2010 to 2018 amongPLHCV and from 20.0 to 57.1 per 100,000 PY for HCV-negative individuals over the same period. The proportion of deaths attributable to drugs among PLHCV and HCV-negative individuals increased from 15.1% to 26.1% and 3.1% to 8.0%, in 2010 and 2018, respectively. The proportion of DRDs attributed solely to synthetic opioids such as fentanyl averaged across both groups increased from 2.1% in 2010 to 69.6% in 2017.

CONCLUSION

Steep drug-related mortality increases among PLHCV and HCV-negative individuals over the last decade highlight the urgent need to address overdose-related drivers and harms in these populations using an integrated care approach.

Comparative effectiveness of buprenorphine-naloxone versus methadone for treatment of opioid use disorder: a population-based observational study protocol in British Columbia, Canada

INTRODUCTION

Despite a recent meta-analysis including 31 randomised controlled trials comparing methadone and buprenorphine for the treatment of opioid use disorder, important knowledge gaps remain regarding the long-term effectiveness of different treatment modalities across individuals, including rigorously collected data on retention rates and other treatment outcomes. Evidence from real-world data represents a valuable opportunity to improve personalised treatment and patient-centred guidelines for vulnerable populations and inform strategies to reduce opioid-related mortality. Our objective is to determine the comparative effectiveness of methadone versus buprenorphine/naloxone, both overall and within key populations, in a setting where both medications are simultaneously available in office-based practices and specialised clinics.

METHODS AND ANALYSIS

We propose a retrospective cohort study of all adults living in British Columbia receiving opioid agonist treatment (OAT) with methadone or buprenorphine/naloxone between 1 January 2008 and 30 September 2018. The study will draw on seven linked population-level administrative databases. The primary outcomes include retention in OAT and all-cause mortality. We will determine the effectiveness of buprenorphine/naloxone vs methadone using intention-to-treat and per-protocol analyses-the former emulating flexible-dose trials and the latter focusing on the comparison of the two medication regimens offered at the optimal dose. Sensitivity analyses will be used to assess the robustness of results to heterogeneity in the patient population and threats to internal validity.

ETHICS AND DISSEMINATION

The protocol, cohort creation and analysis plan have been approved and classified as a quality improvement initiative exempt from ethical review (Providence Health Care Research Institute and the Simon Fraser University Office of Research Ethics). Dissemination is planned via conferences and publications, and through direct engagement and collaboration with entities that issue clinical guidelines, such as professional medical societies and public health organisations.

Evaluating differences in opioid and stimulant use-associated infectious disease hospitalizations in Florida, 2016-2017

Background

The opioid epidemic has led to increases in injection drug use (IDU)-associated infectious diseases; however, little is known about how more recent increases in stimulant use have affected the incidence and outcomes of hospitalizations for infections among people who inject drugs (PWID).

Methods

All hospitalizations of PWID for IDU-associated infections in Florida were identified using administrative diagnostic codes and were grouped by substance used (opioids, stimulants, or both) and site of infection. We evaluated the association between substance used and the outcomes: patient-directed discharge (PDD, or “against medical advice”) and in-hospital mortality.

Results

There were 22 856 hospitalizations for infections among PWID. Opioid use was present in 73%, any stimulants in 43%, and stimulants-only in 27%. Skin and soft tissue infection was present in 50%, sepsis/bacteremia in 52%, osteomyelitis in 10%, and endocarditis in 10%. PWID using opioids/stimulants were youngest, most uninsured, and had the highest rates of endocarditis (16%) and hepatitis C (44%). Additionally, 25% of patients with opioid/stimulant use had PDD versus 12% for those using opioids-only. In adjusted models, opioid/stimulant use was associated with PDD compared to opioid-only use (aRR 1.28, 95% CI 1.17–1.40). Younger age and endocarditis were also associated with PDD. Compared to opioid-only use, stimulant-only use had higher risk of in-hospital mortality (aRR 1.26, 95% CI 1.03–1.46).

Conclusions

While opioid use contributed to most IDU-associated infections, many hospitalizations also involved stimulants. Increasing access to harm reduction interventions could help prevent these infections, while further research on the acute management of stimulant use disorder-associated infections is needed.