The risk of infective endocarditis among people who inject drugs: a retrospective, population-based time series analysis

Patient characteristics, treatment patterns, and prognosis in drug-use-associated infective endocarditis in Denmark from 1999 to 2018

BACKGROUND

While the proportion of drug-use-associated infective endocarditis (DU-IE) has been increasing during the opioid crisis in the United States, it is unknown whether this is seen in Denmark, where several preventive means have been implemented. We aimed to assess the temporal proportion of DU-IE and examine the rate of IE recurrence and mortality.

METHODS

This nationwide cohort study identified all patients with first-time infective endocarditis in 1999-2018. Drug use was defined using ICD-8/10 codes or prescription filling of medication for opioid use disorder. Long-term mortality was examined with a Kaplan-Meier estimator and a multivariate Cox model. The recurrence of IE was examined with the Aalen-Johansen method and a multivariate cause-specific hazard model.

RESULTS

We included 8,843 patients with IE: 407 with DU-IE (60.7% male, median age 43.8 years) and 8,436 with non-DU-IE (65.8% male, median age 71.5 years). The proportion of DU-IE decreased from 5.9% to 3.8% during our study period. The one-year cumulative incidence of all-cause mortality was 16.9% (CI 12.9%-20.8%) for patients with DU-IE and 17.3% (CI 16.4%-18.2%) for patients with non-DU-IE. Drug use was associated with higher one-year mortality (adjusted HR 1.64 (CI 1.23%-2.21%)). The 1-year cumulative incidence of IE recurrence was 12.8% (CI 9.3%-16.3%) in patients with DU-IE and 4.3% (CI 3.8%-4.8%) in patients with non-DU-IE. Drug use was associated with a higher 1-year recurrence of IE (adjusted HR 3.39 (CI 2.35-4.88)).

CONCLUSION

In Denmark, the proportion of patients with DU-IE fell by one-third from 1999 to 2018. DU-IE was associated with higher mortality and recurrence rates than non-DU-IE.

Partial oral versus full intravenous antibiotic treatment of endocarditis in people who inject drugs: A systematic review

Background

Prolonged intravenous (IV) antibiotic therapy may not be optimal for people who inject drugs (PWID) with infective endocarditis (IE) due to unique social and medical needs. The role of partial IV antibiotic therapy with continued oral (PO) antibiotic therapy is unclear.

Methods

A systematic review was performed using EMBASE and MEDLINE databases. Included studies compared PO to IV antibiotic treatment for IE in PWID.

Results

Four studies met eligibility. Observational studies included full IV treatment groups and partial IV, partial PO treatment groups for severe injection-related infections. PWID with IE comprised 41.0%-64.7% of the study populations but outcomes specific to IE were not separately reported. All-cause 90-day readmission rates were comparable between the IV treatment group (27.9%-31.5%) and partial IV, partial PO treatment group (24.8%-32.5%). Ninety-day mortality was non-significantly different between IV treatment (4.9%-10.7%) and partial IV, partial PO treatment groups (2.4%-13.0%). One small randomized clinical trial compared IV oxacillin or vancomycin with gentamicin to PO ciprofloxacin plus rifampin. The cure rates were 91% and 90%, respectively.

Conclusion

There is limited evidence comparing IV treatment to partial IV, partial PO antibiotic treatment in PWID with IE. Observational studies suggest that PO antibiotic therapy after initial IV treatment may be equivalent to full IV treatment alone within specific parameters, but randomized trials are needed to inform recommendations. Substantial clinical and social benefits for PWID and advantages for the health care system will result if PO treatment strategies with equal efficacy can be implemented.

Controlled-release hydromorphone and risk of infection in adults: a systematic review

BACKGROUND

Preliminary evidence suggests that people who inject drugs (PWID) may be at an increased risk of developing infective endocarditis (IE), hepatitis C virus (HCV) infection, and/or human immunodeficiency virus (HIV) infection from hydromorphone controlled-release formulation. The hypothesized mechanism is related to insolubility of the drug, which promotes reuse, leading to contamination of injecting equipment. However, this relationship has not been confirmed. We aimed to conduct a systematic review including adult PWID exposed to controlled-release hydromorphone and the risk of acquiring IE, HCV, and HIV.

METHODS

We searched MEDLINE, EMBASE, and Evidence Based Medicine reviews from inception until September 2021. Following pilot testing, two reviewers conducted all screening of citations and full-text articles, as well as abstracted data, and appraised risk of bias using the Newcastle-Ottawa scale and Effective Practice and Organization of Care tool. Equity issues were examined using the PROGRESS-PLUS framework. Discrepancies were resolved consistently by a third reviewer. Meta-analysis was not feasible due to heterogeneity across the studies.

RESULTS

After screening 3,231 citations from electronic databases, 722 citations from unpublished sources/reference scanning, and 626 full-text articles, five studies were included. Five were cohort studies, and one was a case-control study. The risk of bias varied across the studies. Two studies reported on gender, as well as other PROGRESS-PLUS criteria (race, housing, and employment). Three studies focused specifically on the controlled-release formulation of hydromorphone, whereas two studies focused on all formulations of hydromorphone. One retrospective cohort study found an association between controlled-release hydromorphone and IE, whereas a case-control study found no evidence of an association. One retrospective cohort study found an association between the number of hydromorphone controlled-release prescriptions and prevalence of HCV. None of the studies specifically reported on associations with HIV.

DISCUSSION

Very few studies have examined the risk of IE, HCV, and HIV infection after exposure to controlled-release hydromorphone. Very low-quality and scant evidence suggests uncertainty around the risks of blood-borne infections, such as HCV and IE to PWID using this medication.

The Epidemiology of Infective Endocarditis in New South Wales, Australia: A Retrospective Cross-Sectional Study From 2001 to 2020

OBJECTIVES

This study aimed to investigate the demographic differences amongst patients diagnosed with infective endocarditis (IE), predictors of adverse events, and the association between clinical decision-making and adverse health outcomes amongst patients with IE.

DESIGN

A retrospective cross-sectional study was conducted using the New South Wales (NSW) Admitted Patient Data Collection (APDC) from the Centre for Health Record Linkage (CHeReL).

PARTICIPANTS

All patients (N=18,044) from 2001 to 2020 in New South Wales who received a diagnosis of IE using ICD-10-AM diagnostic code 133.0 were included.

METHODS

Categorical variables were compared using the chi-square test or Fisher's exact test, while the t-test was used for continuous variables. The association between clinical decision-making and adverse health outcomes amongst patients with IE were examined via generalised linear mixed models.

RESULTS

Sex, age, birthplace and referral impacted clinical decision-making, in-hospital death and severity of the disease. Women experienced a higher risk of death and fewer escalations of care. Admission and mortality increased with age, with those aged 60 and above responsible for 60.8% of hospitalisations. Despite octogenarians making up one-fifth of admissions and having the worst mortality rate (15.1%), they experienced only one in 10 intensive care (ICU) admissions. Overseas-born patients had fewer escalations of care and experienced less severe disease if referred by a medical practitioner. One out of 10 admissions that resulted in a hospital death were given non-emergency status, and one in two ICU patients died in hospital.

CONCLUSIONS

Sex, age, place of birth, and clinical decision-making were important predictors of severe disease and death in hospital, lending weight that health care clinical decisions may adversely impact health outcomes for populations of interest.

Implementation of an integrated infectious disease and substance use disorder team for injection drug use-associated infections: a qualitative study

BACKGROUND

Hospitalizations for severe injection drug use-related infections (SIRIs) are characterized by high costs, frequent patient-directed discharge, and high readmission rates. Beyond the health system impacts, these admissions can be traumatizing to people who inject drugs (PWID), who often receive inadequate treatment for their substance use disorders (SUD). The Jackson SIRI team was developed as an integrated infectious disease/SUD treatment intervention for patients hospitalized at a public safety-net hospital in Miami, Florida in 2020. We conducted a qualitative study to identify patient- and clinician-level perceived implementation barriers and facilitators to the SIRI team intervention.

METHODS

Participants were patients with history of SIRIs (n = 7) and healthcare clinicians (n = 8) at one implementing hospital (Jackson Memorial Hospital). Semi-structured qualitative interviews were performed with a guide created using the Consolidated Framework for Implementation Research (CFIR). Interviews were transcribed, double coded, and categorized by study team members using CFIR constructs.

RESULTS

Implementation barriers to the SIRI team intervention identified by participants included: (1) complexity of the SIRI team intervention; (2) lack of resources for PWID experiencing homelessness, financial insecurity, and uninsured status; (3) clinician-level stigma and lack of knowledge around addiction and medications for opioid use disorder (OUD); and (4) concerns about underinvestment in the intervention. Implementation facilitators of the intervention included: (1) a non-judgmental, harm reduction-oriented approach; (2) the team's advocacy for PWID as a means of institutional culture change; (3) provision of close post-hospital follow-up that is often inaccessible for PWID; (4) strong communication with patients and their hospital physicians; and (5) addressing diverse needs such as housing, insurance, and psychological wellbeing.

CONCLUSION

Integration of infectious disease and SUD treatment is a promising approach to managing patients with SIRIs. Implementation success depends on institutional buy-in, holistic care beyond the medical domain, and an ethos rooted in harm reduction across multilevel (inner and outer) implementation contexts.

Population study of sex-based outcomes after surgical aortic valve replacement

Background

Surgical aortic valve replacement (SAVR) is a key strategy for the treatment of aortic valve disease. However, studies have involved primarily male patients, and whether the benefits of this approach can be extrapolated to female patients is unclear.

Methods

Clinical and administrative datasets for 12,207 patients undergoing isolated SAVR in Ontario from 2008 to 2019 were linked. Male and female patients were balanced using inverse probability treatment weighting. Mortality, endocarditis, and major hemorrhagic and thrombotic events, as well as 2 composite outcomes-major adverse cerebral and cardiovascular events (MACCE) and patient-derived adverse cardiovascular and noncardiovascular events (PACE)-and their component events, were compared in the weighted groups with a stratified log-rank test.

Results

A total of 7485 male patients and 4722 female patients were included in the study. Median follow-up was 5.2 years in both sexes. All-cause mortality did not differ between sexes (hazard ratio [HR] 0.949 [95% confidence interval {CI} 0.851-1.059]). Male sex was associated with an increased risk of new-onset dialysis (HR 0.689 [95% CI 0.488-0.974]). Female sex was associated with a significantly increased risk of both new-onset heart failure (HR 1.211 [95% CI 1.051-1.394], P = 0.0081) and heart failure hospitalization (HR 1.200 [95% CI 1.036-1.390], P = 0.015). No statistically significant differences were seen in any of the other secondary outcomes between sexes.

Conclusions

This population health study demonstrated that survival did not differ between male and female patients undergoing SAVR. Significant sex-related differences were found in the risk of heart failure and new-onset dialysis, but these findings should be considered exploratory and require further study.

Sensitivity, specificity and predictive values of ICD-10 substance use codes in a cohort of substance use-related endocarditis patients

Background: Healthcare databases have the potential to become efficient tools for epidemiological research in People Who Inject Drugs (PWID). The validity of ICD-10 codes for specific substances in this population has not been assessed.Objectives: Validate ICD-10 diagnosis codes relating to the use of specific substance classes in a cohort of endocarditis patients.Methods: Our study sample consisted of 379 first-episode infective endocarditis patients (Male: 208, Female: 171), aged 18-55, admitted to any of three hospitals in London, Ontario from 2007 to 2018. Of these, 287 used drugs. We validated ICD-10 substance use codes for opioids (F11), stimulants (F15), cocaine (F14) and multiple substances (F19). Sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were calculated for each code, using self-reported substance use documented on medical record review as a gold standard. We conducted a comparative analysis between code-negative users and code-positive users for each substance.Results: All substance use codes shared the same pattern: high specificity, high PPV and low sensitivity, with code F11 yielding the highest PPV (96.3%; 95% C.I.: 90.8-98.6) and sensitivity (42.6%; 95% C.I. 36.3-49.1). The code-positives and code-negatives for each substance did not differ significantly in any characteristics compared.Conclusion: Our results suggest that the individual ICD-10 codes analyzed should not be used for research without adjustment for low sensitivity. However, due to high PPV and specificity, these codes may still have potential for research use. Because code-negative patients did not differ from code-positive patients, their data may be extrapolated to the overall group of substance users.

Peripherally Inserted Central Catheter Line Misuse Among People Who Inject Drugs While on Therapy for Infective Endocarditis

BACKGROUND

People who inject drugs and have infective endocarditis have a high risk of recurrent infective endocarditis and death. We aimed to characterize clinical factors associated with mortality and assess the probability of infective endocarditis recurrence in the presence of death as a competing risk.

METHODS

A retrospective cohort study was conducted of people who inject drugs, identified between April 5, 2007 and March 15, 2018 with the Modified Duke Criteria for definite infective endocarditis. Fine-Gray sub-distribution and Cox proportional hazards modeling were conducted to determine variables associated with the rate of infective endocarditis recurrence and mortality, respectively.

RESULTS

Of the 310 patients with infective endocarditis who inject drugs, 236 experienced a single episode and 74 experienced recurrent episodes. Peripherally inserted central catheter misuse was associated with an increased rate of infective endocarditis recurrence (sub-distribution hazard ratio 2.41; 95% confidence interval [CI], 1.17-4.98; P = .02) and mortality (hazard ratio [HR] 2.44; 95% CI, 1.15-5.17; P = .02). Non-right-sided infection, peripheral intravenous therapy, and intensive care unit admission were also associated with increased mortality. Oral therapy (HR 0.38; 95% CI, 0.16-0.91; P = .03), outpatient treatment (HR 0.39; 95% CI, 0.19-0.82; P = .01), and inpatient referral to addiction services (HR 0.39; 95% CI, 0.22-0.70; P = .002) were associated with a decrease in mortality.

CONCLUSIONS

Patients who misuse their peripherally inserted central catheter are at higher risk of recurrent infective endocarditis and death. Avoidance of peripherally inserted central catheter lines and use of intravenous peripheral therapy did not reduce mortality, but oral therapy was associated with reduced risk. Inpatient addiction services referral is important.

Different drugs, different sides: injection use of opioids alone, and not stimulants alone, predisposes to right-sided endocarditis

Objectives

Many studies suggest that infective endocarditis (IE) in people who inject drugs is predominantly right sided, while other studies suggest left sided disease; few have differentiated by class of drug used. We hypothesised that based on differing physiological mechanisms, opioids but not stimulants would be associated with right sided IE.

Methods

A retrospective case series of 290 adult (age ≥18) patients with self-reported recent injection drug use, admitted for a first episode of IE to one of three hospitals in London Ontario between April 2007 and March 2018, stratified patients by drug class used (opioid, stimulant or both), and by site of endocarditis. Other outcomes captured included demographics, causative organisms, cardiac and non-cardiac complications, referral to addiction services, medical versus surgical management, and survival.

Results

Of those who injected only opioids, 47/71 (69%) developed right-sided IE, 17/71 (25%) developed left-sided IE and 4/71 (6%) had bilateral IE. Of those who injected only stimulants, 11/24 (46%) developed right-sided IE, 11/24 (46%) developed left-sided IE and 2/24 (8%) had bilateral IE. Relative to opioid-only users, stimulant-only users were 1.75 (95% CI 1.05 to 2.93; p=0.031) times more likely to have a left or bilateral IE versus right IE.

Conclusions

While injection use of opioids is associated with a strong predisposition to right-sided IE, stimulants differ in producing a balanced ratio of right and left-sided disease. As the epidemic of crystal methamphetamine injection continues unabated, the rate of left-sided disease, with its attendant higher morbidity and mortality, may also grow.

"I have such a hard time hitting myself, I thought it'd be easier": perspectives of hospitalized patients on injecting drugs into vascular access devices

Background

Hospital patients who use drugs may require prolonged parenteral antimicrobial therapy administered through a vascular access device (VAD). Clinicians’ concerns that patients may inject drugs into these devices are well documented. However, the perspectives of patients on VAD injecting are not well described, hindering the development of informed clinical guidance. This study was conducted to elicit inpatient perspectives on the practice of injecting drugs into VADs and to propose strategies to reduce associated harms.

Methods

Researchers conducted a focused ethnography and completed semi-structured interviews with 25 inpatients at a large tertiary hospital in Western Canada that experiences a high rate of drug-related presentations annually.

Results

A few participants reported injecting into their VAD at least once, and nearly all had heard of the practice. The primary reason for injecting into a VAD was easier venous access since many participants had experienced significant vein damage from injection drug use. Several participants recognized the risks associated with injecting into VADs, and either refrained from the practice or took steps to maintain their devices while using them to inject drugs. Others were uncertain how the devices functioned and were unaware of potential harms.

Conclusions

VADs are important for facilitating completion of parenteral antimicrobial therapy and for other medically necessary care. Prematurely discharging patients who inject into their VAD from hospital, or discontinuing or modifying therapy, results in inequitable access to health care for a structurally vulnerable patient population. Our findings demonstrate a need for healthcare provider education and non-stigmatizing clinical interventions to reduce potential harms associated with VAD injecting. Those interventions could include providing access to specialized pain and withdrawal management, opioid agonist treatment, and harm reduction services, including safer drug use education to reduce or prevent complications from injecting drugs into VADs.

Temporal trends and patterns of infective endocarditis in a Chinese population: A territory-wide study in Hong Kong (2002–2019)

Background

The characteristics of infective endocarditis (IE) in Asians are poorly understood. Therefore, we aim to describe the epidemiological trends and clinical features of IE in Hong Kong.

Methods

All patients with incident IE from 2002–2019 in a territory-wide clinical database in Hong Kong were identified. We studied the age- and sex-adjusted and one-year mortality of IE between 2002 and 2019 and identified significant contributors to 1-year all-cause death using the attributable fraction. We used propensity score and inverse propensity of treatment weighting to study the association of surgery with mortality.

Findings

A total of 5139 patients (60.4 ± 18.2years, 37% women) were included. The overall incidence of IE was 4.9 per 100,000 person-year, which did not change over time (P = 0.17). Patients in 2019 were older and more comorbid than those in 2002. The one-year crude mortality rate was 30% in 2002, which did not change significantly over time (P = 0.10). Between 2002 and 2019, the rate of surgery increased and was associated with a 51% risk reduction in 1-year all-cause mortality (Hazard Ratio 0.49 [0.28–0.87], P = 0.015). Advanced age (attributable fraction 19%) and comorbidities (attributable fraction 15%) were significant contributors to death.

Interpretation

The incidence of IE in Hong Kong did not change between 2002 and 2019. Patients with IE in 2019 were older and had more comorbidities than those in 2002. Mortality of IE remains persistently high in Hong Kong. Together, these data can guide public health strategies to improve the outcomes of patients with IE.

Funding

This work was supported by Sanming Project of Medicine in Shenzhen, China [No. SZSM201911020] and HKU-SZH Fund for Shenzhen Key Medical Discipline [No. SZXK2020081].

Unequal access to opioid agonist treatment and sterile injecting equipment among hospitalized patients with injection drug use-associated infective endocarditis

BACKGROUND

Addiction treatment and harm reduction services reduce risks of death and re-infection among patients with injection drug use-associated infective endocarditis (IDU-IE), but these are not offered at many hospitals. Among hospitalized patients with IDU-IE at the two tertiary-care hospitals in the Canadian Maritimes, we aimed to identify (1) the availability of opioid agonist treatment (OAT) and sterile drug injecting equipment, and (2) indicators of potential unmet addiction care needs.

METHODS

Retrospective review of IDU-IE hospitalizations at Queen Elizabeth II Health Sciences Centre (Halifax, Nova Scotia) and the Saint John Regional Hospital (Saint John, New Brunswick), October 2015 -March 2017. In Halifax, there are no addiction medicine providers on staff; in Saint John, infectious diseases physicians also practice addiction medicine. Inclusion criteria were: (1) probable or definite IE as defined by the modified Duke criteria; and (2) injection drug use within the prior 3 months.

RESULTS

We identified 38 hospitalizations (21 in Halifax and 17 in Saint John), for 30 unique patients. Among patients with IDU-IE and untreated opioid use disorder, OAT was offered to 36% (5/14) of patients in Halifax and 100% (6/6) of patients in Saint John. Once it was offered, most patients at both sites initiated OAT and planned to continue it after discharge. In Halifax, no patients were offered sterile injecting equipment, and during five hospitalizations staff confiscated patients' own equipment. In Saint John, four patients were offered (and one was provided) injecting equipment in hospital, and during two hospitalizations staff confiscated patients' own equipment. Concerns regarding undertreated pain or opioid withdrawal were documented during 66% (25/38) of hospitalizations, and in-hospital illicit or non-medical drug use during 32% (12/38). Two patients at each site (11%; 4/38) had self-directed discharges against medical advice.

CONCLUSIONS

Patients with IDU-IE in the Canadian Maritimes have unequal access to evidence-based addiction care depending on where they are hospitalized, which differs from the community-based standard of care. Indicators of potential unmet addiction care needs in hospital were common.

The Second Heart Program-A multidisciplinary team supporting people who inject drugs with infective endocarditis: Protocol of a feasibility study

Introduction

Infective endocarditis (IE) is a severe and highly prevalent infection among people who inject drugs (PWID). While short-term (30-day) outcomes are similar between PWID and non-PWID, the long-term outcomes among PWID after IE are poor, with 1-year mortality rates in excess of 25%. Novel clinical interventions are needed to address the unique needs of PWID with IE, including increasing access to substance use treatment and addressing structural barriers and social determinants of health.

Methods and analysis

PWID with IE will be connected to a multidisciplinary team that will transition with them from hospital to the community. The six components of the Second Heart Team are: (1) peer support worker with lived experience, (2) systems navigator, (3) addiction medicine physician, (4) primary care physician, (5) infectious diseases specialist, (6) cardiovascular surgeon. A convergent mixed-methods study design will be used to test the feasibility of this intervention. We will concurrently collect quantitative and qualitative data and ‘mix’ at the interpretation stage of the study to answer our research questions.

Ethics and dissemination

This study has been approved by the Hamilton Integrated Research Ethics Board (Project No. 7012). Results will be presented at national and international conferences and submitted for publication in a scientific journal.

Clinical trail registrarion

Trial registration number: ISRCTN14968657 https://www.isrctn.com/ISRCTN14968657.

Trends in Hospitalizations for Serious Infections Among People With Opioid Use Disorder in Ontario, Canada

Opioid use among people who inject drugs can lead to serious complications, including infections. We sought to study trends in rates of these complications among people with an opioid use disorder (OUD) and the sequelae of those hospitalizations.

Impact of the Opioid Epidemic

In recent years the prescription opioid overdose epidemic has decreased, but has been more than offset by increases in overdose caused by fentanyl and fentanyl analogues. Opioid overdose patients should receive naloxone if they have significant respiratory depression and/or loss of protective airway reflexes. Patients who receive naloxone should be observed for recurrent opioid effects. Patients with opioid overdose may be admitted to the intensive care unit for naloxone infusions, treatment of noncardiogenic pulmonary edema, autonomic instability, or sequelae of hypoxia-ischemia or cardiac arrest. Primary and secondary prevention are important to reduce the number of people with life-threatening opioid overdose.

Social and structural determinants of injecting-related bacterial and fungal infections among people who inject drugs: protocol for a mixed studies systematic review

INTRODUCTION

Injecting-related bacterial and fungal infections are a common complication among people who inject drugs (PWID), associated with significant morbidity and mortality. Invasive infections, including infective endocarditis, appear to be increasing in incidence. To date, preventive efforts have focused on modifying individual-level risk behaviours (eg, hand-washing and skin-cleaning) without much success in reducing the population-level impact of these infections. Learning from successes in HIV prevention, there may be great value in looking beyond individual-level risk behaviours to the social determinants of health. Specifically, the risk environment conceptual framework identifies how social, physical, economic and political environmental factors facilitate and constrain individual behaviour, and therefore influence health outcomes. Understanding the social and structural determinants of injecting-related bacterial and fungal infections could help to identify new targets for prevention efforts in the face of increasing incidence of severe disease.

METHODS AND ANALYSIS

This is a protocol for a systematic review. We will review studies of PWID and investigate associations between risk factors (both individual-level and social/structural-level) and the incidence of hospitalisation or death due to injecting-related bacterial infections (skin and soft-tissue infections, bacteraemia, infective endocarditis, osteomyelitis, septic arthritis, epidural abscess and others). We will include quantitative, qualitative and mixed methods studies. Using directed content analysis, we will code risk factors for these infection-related outcomes according to their contributions to the risk environment in type (social, physical, economic or political) and level (microenvironmental or macroenvironmental). We will also code and present risk factors at each stage in the process of drug acquisition, preparation, injection, superficial infection care, severe infection care or hospitalisation, and outcomes after infection or hospital discharge.

ETHICS AND DISSEMINATION

As an analysis of the published literature, no ethics approval is required. The findings will inform a research agenda to develop and implement social/structural interventions aimed at reducing the burden of disease.

PROSPERO REGISTRATION NUMBER

CRD42021231411.

Association of Nonacute Opioid Use and Cardiovascular Diseases: A Scoping Review of the Literature

BACKGROUND In this scoping review, we identified and reviewed 23 original articles from the PubMed database that investigated the relationship between nonacute opioid use (NOU) and cardiovascular outcomes. METHODS AND RESULTS We defined NOU to include both long-term opioid therapy and opioid use disorder. We summarized the association between NOU and 5 classes of cardiovascular disease, including infective endocarditis, coronary heart disease (including myocardial infarction), congestive heart failure, cardiac arrythmia (including cardiac arrest), and stroke. The most commonly studied outcomes were coronary heart disease and infective endocarditis. There was generally consistent evidence of a positive association between community prevalence of injection drug use (with opioids being the most commonly injected type of drug) and community prevalence of infective endocarditis, and between (primarily medically indicated) NOU and myocardial infarction. There was less consensus about the relationship between NOU and congestive heart failure, cardiac arrhythmia, and stroke. CONCLUSIONS There is a dearth of high-quality evidence on the relationship between NOU and cardiovascular disease. Innovative approaches to the assessment of opioid exposure over extended periods of time will be required to address this need.

Exploring care of hospital inpatients with substance involvement

INTRODUCTION

This article presents demographic and care factors related to persons who are substance-involved and require inpatient administration of intravenous antibiotics.

PURPOSE

This study was conducted to explore healthcare responses to support substance-involved inpatients, through exploration of documented client outcomes, healthcare provider accounts, and representation of clients through documentation.

METHOD(S)

A patient-oriented research team undertook this multiple methods, exploratory study. A health record review included people admitted to a complex continuing care hospital, within a 2-year period, for long-term antibiotic treatment and concurrent illicit substance use. Correlations were examined between whether or not clients were discharged against medical advice (AMA) in comparison to demographic, medical, and care-related factors. Qualitative analysis of narrative health record data was undertaken. Semi-structured interviews of healthcare providers and decision makers were conducted.

RESULTS

Twenty-five people met recruitment criteria for health record review; three people were admitted twice, resulting in 28 admissions. Interviews with seven healthcare providers and decision makers uncovered themes of client autonomy, professional liability, client responsibility, the "right" service, and burnout, hopelessness, and helplessness.

CONCLUSION

Recommended strategies to effectively respond to substance use among clients admitted for general medical concerns are: i) support inpatients with complex health needs, including substance use, ii) ensure substance use and addiction services are integrated into all inpatient practice areas, iii) support effective harm reduction practices for hospital-admitted clients, and iv) develop robust policies and protocols to support healthcare providers and inpatients.

Burden of infective endocarditis in an Australian cohort of people who inject drugs

BACKGROUND

Infective endocarditis (IE) results in substantial morbidity and mortality in people who inject drugs (PWID).

AIMS

To describe the burden of IE and its outcomes in PWID.

METHODS

Retrospective cohort study of adults admitted to a tertiary referral centre in Melbourne, Australia, with IE due to injection drug use from 1997 to 2015.

RESULTS

Ninety-seven PWID with 127 episodes of IE were identified with a median acute inpatient stay of 37 days (1-84). Admission to an intensive care unit was required in 67/127 (53%) episodes. Twenty-seven percent (34/127) of episodes occurred in patients with a previous episode of endocarditis. One third (43/127, 34%) of episodes involved left-sided cardiac valves. Antimicrobial treatment was completed in 88 (70%) episodes. Valve surgery was performed in 25/127 (20%) episodes. Predictors of surgery in univariable analysis were left-sided cardiac involvement (risk ratio (RR) 6.0), severe valvular regurgitation (RR 2.6) and cardiac failure (RR 2.2) (all P < 0.005). Twenty (16%) episodes resulted in death. Predictors of mortality on univariable analysis were left-sided cardiac involvement (RR 6.4), and not completing treatment (RR 0.12; both P < 0.001). The average estimated cost per episode was AU$74 168.

CONCLUSIONS

IE causes a considerable burden of disease in PWID, with significant healthcare utilisation and cost. Surgery and death are not infrequent complications. In addition to ensuring completion of antimicrobial therapy, strategies such as opioid maintenance programmes may be useful in improving health outcomes for PWID.

Misclassification Error-Adjusted Prevalence of Injection Drug Use Among Infective Endocarditis Hospitalizations in the United States: A Serial Cross-Sectional Analysis of the 2007-2016 National Inpatient Sample

Administrative health databases have been used to monitor trends in infective endocarditis hospitalization related to nonprescription injection drug use (IDU) using International Classification of Diseases (ICD) code algorithms. Because no ICD code for IDU exists, drug dependence and hepatitis C virus (HCV) have been used as surrogate measures for IDU, making misclassification error (ME) a threat to the accuracy of existing estimates. In a serial cross-sectional analysis, we compared the unadjusted and ME-adjusted prevalences of IDU among 70,899 unweighted endocarditis hospitalizations in the 2007-2016 National Inpatient Sample. The unadjusted prevalence of IDU was estimated with a drug algorithm, an HCV algorithm, and a combination algorithm (drug and HCV). Bayesian latent class models were used to estimate the median IDU prevalence and 95% Bayesian credible intervals and ICD algorithm sensitivity and specificity. Sex- and age group-stratified IDU prevalences were also estimated. Compared with the misclassification-adjusted prevalence, unadjusted estimates were lower using the drug algorithm and higher using the combination algorithm. The median ME-adjusted IDU prevalence increased from 9.7% (95% Bayesian credible interval (BCI): 6.3, 14.8) in 2008 to 32.5% (95% BCI: 26.5, 38.2) in 2016. Among persons aged 18-34 years, IDU prevalence was higher in females than in males. ME adjustment in ICD-based studies of injection-related endocarditis is recommended.

Injection Drug Use Endocarditis: An Inner-City Hospital Experience

Background

There has been a rise in the incidence of injection drug use and associated infective endocarditis.

Methods

The clinical outcomes of 39 patients admitted with injection drug use-associated infective endocarditis were collected with a mean follow-up of 14 months. The outcomes were compared for patients treated medically with those undergoing surgical intervention. Re sults: The mean age was 39 ± 11 years; 54% were female. Thirty-two patients (82%) had native and 7 (18%) prosthetic infective endocarditis. The tricuspid valve was affected in 17 patients (43%), the mitral in 10 (26%), the aortic in 4 (10%), and multiple valves in 8 (20%). Sixteen (41%) patients underwent surgery, and 23 (59%) were treated with medical therapy. The indications for surgery included heart failure, systemic emboli, recurrent infection, and vegetation size ≥10 mm. Patients undergoing surgery had a higher rate of paravalvular abscess (25% vs 0%, P = 0.02), valve perforation (37% vs 11%, P = 0.04), and mitral valve involvement (44% vs 13%, P = 0.06), whereas medically treated patients had higher tricuspid valve involvement (61% vs 19%, P = 0.02). During follow-up, 26% of medical and 31% of surgical cohort patients died (P = 0.7). Mortality was highest (54%) among those who continued medical management despite an indication for surgery. Univariate predictors of mortality were age (odds ratio [OR] 1.09, 95% confidence interval [CI]: 1.01-1.17; P = 0.02), heart failure (OR 6.9; 95% CI: 1.24-37.49; P = 0.02), septicemia (OR 4.40; 95% CI:0.99-19.54; P = 0.05), and shock (OR 10.8; 95% CI: 1.68-69.92; P = 0.01).

Conclusions

Despite contemporary therapy, patients with injection drug use-associated infective endocarditis remain at high risk of complications and poor clinical outcomes. These findings highlight the need for developing new care pathways and a team approach for effective management.

Prospective Cohort Study of Infective Endocarditis in People Who Inject Drugs

BACKGROUND

Infective endocarditis (IE) in people who inject drugs (PWID) is an emergent public health problem.

OBJECTIVES

The purpose of this study was to investigate IE in PWID and compare it with IE in non-PWID patients.

METHODS

Two prospective cohort studies (ICE-PCS and ICE-Plus databases, encompassing 8,112 IE episodes from 2000 to 2006 and 2008 to 2012, with 64 and 34 sites and 28 and 18 countries, respectively). Outcomes were compared between PWID and non-PWID patients with IE. Logistic regression analyses were performed to investigate risk factors for 6-month mortality and relapses amongst PWID.

RESULTS

A total of 7,616 patients (591 PWID and 7,025 non-PWID) were included. PWID patients were significantly younger (median 37.0 years [interquartile range: 29.5 to 44.2 years] vs. 63.3 years [interquartile range: 49.3 to 74.0 years]; p < 0.001), male (72.5% vs. 67.4%; p = 0.007), and presented lower rates of comorbidities except for human immunodeficiency virus, liver disease, and higher rates of prior IE. Amongst IE cases in PWID, 313 (53%) episodes involved left-side valves and 204 (34.5%) were purely left-sided IE. PWID presented a larger proportion of native IE (90.2% vs. 64.4%; p < 0.001), whereas prosthetic-IE and cardiovascular implantable electronic device-IE were more frequent in non-PWID (9.3% vs. 27.0% and 0.5% vs. 8.6%; both p < 0.001). Staphylococcus aureus caused 65.9% and 26.8% of cases in PWID and non-PWID, respectively (p < 0.001). PWID presented higher rates of systemic emboli (51.1% vs. 22.5%; p < 0.001) and persistent bacteremia (14.7% vs. 9.3%; p < 0.001). Cardiac surgery was less frequently performed (39.5% vs. 47.8%; p < 0.001), and in-hospital and 6-month mortality were lower in PWID (10.8% vs. 18.2% and 14.4% vs. 22.2%; both p < 0.001), whereas relapses were more frequent in PWID (9.5% vs. 2.8%; p < 0.001). Prior IE, left-sided IE, polymicrobial etiology, intracardiac complications, and stroke were risk factors for 6-month mortality, whereas cardiac surgery was associated with lower mortality in the PWID population.

CONCLUSIONS

A notable proportion of cases in PWID involve left-sided valves, prosthetic valves, or are caused by microorganisms other than S. aureus.

Infective Endocarditis in Persons Who Use Drugs: Epidemiology, Current Management, and Emerging Treatments

Infective endocarditis associated with injection drug use (IDU-IE) is markedly increasing in the United States and Canada. Long-term outcomes are dismal and stem from insufficient substance use disorder treatment. In this review, we summarize the principles of antimicrobial and surgical management for infective endocarditis associated with injection drug use. We discuss approaches to opioid use disorder care and harm reduction in the inpatient setting and review opportunities to address preventable infections among persons injecting drugs. We highlight barriers to implementing optimal treatment and consider novel approaches that may reshape infective endocarditis associated with injection drug use treatment in coming years.

Risk of New Bloodstream Infections and Mortality Among People Who Inject Drugs With Infective Endocarditis

IMPORTANCE

People who inject drugs (PWID) who are being treated for infective endocarditis remain at risk of new bloodstream infections (BSIs) due to ongoing intravenous drug use (IVDU).

OBJECTIVES

To characterize new BSIs in PWID receiving treatment for infective endocarditis, to determine the clinical factors associated with their development, and to determine whether new BSIs and treatment setting are associated with mortality.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was performed at 3 tertiary care hospitals in London, Ontario, Canada, from April 1, 2007, to March 31, 2018. Participants included a consecutive sample of all PWID 18 years or older admitted with infective endocarditis. Data were analyzed from April 1, 2007, to June 29, 2018.

MAIN OUTCOMES AND MEASURES

New BSIs and factors associated with their development, treatment setting of infective endocarditis episodes (ie, inpatient vs outpatient), and 90-day mortality.

RESULTS

The analysis identified 420 unique episodes of infective endocarditis in 309 PWID (mean [SD] patient age, 35.7 [9.7] years; 213 episodes [50.7%] involving male patients), with 82 (19.5%) complicated by new BSIs. There were 138 independent new BSIs, of which 68 (49.3%) were polymicrobial and 266 were unique isolates. Aerobic gram-negative bacilli (143 of 266 [53.8%]) and Candida species (75 of 266 [28.2%]) were the most common microorganisms. Ongoing inpatient IVDU was documented by a physician in 194 infective endocarditis episodes (46.2%), and 127 of these (65.5%) were confirmed by urine toxicology results. Multivariable time-dependent Cox regression demonstrated that previous infective endocarditis (hazard ratio [HR], 1.89; 95% CI, 1.20-2.98), inpatient treatment (HR, 4.49; 95% CI, 2.30-8.76), and physician-documented inpatient IVDU (HR, 5.07; 95% CI, 2.68-9.60) were associated with a significantly higher rate of new BSIs, whereas inpatient addiction treatment was associated with a significantly lower rate (HR, 0.53; 95% CI, 0.32-0.88). New BSIs were not significantly associated with 90-day mortality (HR, 1.76; 95% CI, 0.78-4.02); significant factors associated with mortality included inpatient infective endocarditis treatment (HR, 3.39; 95% CI, 1.53-7.53), intensive care unit admission (HR, 9.51; 95% CI, 4.91-18.42), and methicillin-resistant Staphylococcus aureus infective endocarditis (HR, 1.77; 95% CI, 1.03-3.03), whereas right-sided infective endocarditis was associated with a significantly lower mortality rate (HR, 0.41; 95% CI, 0.25-0.67).

CONCLUSIONS AND RELEVANCE

In this study, new BSIs were common in PWID receiving parenteral treatment for infective endocarditis. Discharging patients to outpatient treatment was not associated with an increase in new BSI incidence or mortality; carefully selected PWID may therefore be considered for such treatment.

New hepatitis C diagnoses in Ontario, Canada are associated with the local prescription patterns of a controlled-release opioid

Increases in acute hepatitis C virus (HCV) incidence may be a result of the rising prevalence of injection drug use and the opioid epidemic. Among persons who inject drugs, sharing of needles/syringes is less common and leads to a smaller proportion of incident cases than does sharing of injection drug preparation equipment. In Canada and Europe, hydromorphone controlled release has been associated with frequent reuse and sharing of IDPE. Drug excipients within HCR have been shown to preserve virus survival within IDPE. We hypothesized that regional differences in HCV incidence would mirror regional differences in HCR prescribing. We reviewed HCV incidence data across Ontario, Canada for 2016. Opioid prescribing patterns in each Health Unit were reviewed. Multivariable Poisson regression analyses were performed to test the strength of hydromorphone controlled release dispensing patterns in explaining HCV incidence compared to all opioids. Less vehicle access, lack of education, lower income, less population density, higher white race/ethnicity and more opioid substitution therapy recipients remained significant positive predictors of hepatitis C incidence in the Ontario model. Higher hydromorphone controlled release dispensing rate was a stronger predictor of HCV incidence than all opioid prescriptions (standardized risk ratio = 1.17, P < .0001 vs sRR = 1.11, P = .02). When hydromorphone controlled release was excluded from the opioid prescription variable, dispensing patterns of all other opioids no longer remained a significant predictor (sRR = 1.042, P = .34). The observed relationship between HCV incidence and hydromorphone controlled release dispensing suggests that the type of opioid prescribed locally may contribute to variations in HCV incidence. These data add support to evidence that hydromorphone controlled release use is contributing to HCV spread in Ontario.

Numerous outbreaks amongst homeless and injection drug-using populations raise concerns of an evolving syndemic in London, Canada

London, Ontario is a mid-sized Canadian city which appears to be experiencing a syndemic predominately amongst its marginalized populations. Since 2014, rates of HIV, hepatitis A (HAV), hepatitis C (HCV), and invasive group A streptococcal disease have climbed well above provincial rates amid increasing use of injection drugs. Rates of infective endocarditis have also been on the rise. Extensive public health and community-based efforts were taken in response to these concurrent outbreaks. These efforts included establishing improved client care pathways, creating specialized teams to engage underhoused clients, providing mass immunization, and developing new health promotion campaigns. Rates of HIV and HAV were subsequently controlled locally while rates of HCV, iGAS and infective endocarditis remain high within the community and throughout the province.

Risk factors of infective endocarditis in persons who inject drugs

BACKGROUND

The rising incidence of infective endocarditis (IE) among people who inject drugs (PWID) has been a major concern across North America. The coincident rise in IE and change of drug preference to hydromorphone controlled-release (CR) among our PWID population in London, Ontario intrigued us to study the details of injection practices leading to IE, which have not been well characterized in literature.

METHODS

A case-control study, using one-on-one interviews to understand risk factors and injection practices associated with IE among PWID was conducted. Eligible participants included those who had injected drugs within the last 3 months, were > 18  years old and either never had or were currently admitted for an IE episode. Cases were recruited from the tertiary care centers and controls without IE were recruited from outpatient clinics and addiction clinics in London, Ontario.

RESULTS

Thirty three cases (PWID IE+) and 102 controls (PWID but IE-) were interviewed. Multivariable logistic regressions showed that the odds of having IE were 4.65 times higher among females (95% CI 1.85, 12.28; p = 0.001) and 5.76 times higher among PWID who did not use clean injection equipment from the provincial distribution networks (95% CI 2.37, 14.91; p < 0.001). Injecting into multiple sites and heating hydromorphone-CR prior to injection were not found to be significantly associated with IE. Hydromorphone-CR was the most commonly injected drug in both groups (90.9% cases; 81.4% controls; p = 0.197).

DISCUSSION

Our study highlights the importance of distributing clean injection materials for IE prevention. Furthermore, our study showcases that females are at higher risk of IE, which is contrary to the reported literature. Gender differences in injection techniques, which may place women at higher risk of IE, require further study. We suspect that the very high prevalence of hydromorphone-CR use made our sample size too small to identify a significant association between its use and IE, which has been established in the literature.

Epidemiology, Microbiology, and Clinical Outcomes Among Patients With Intravenous Drug Use-Associated Infective Endocarditis in New Brunswick

Background

Within the context of Canada’s opioid crisis, medical complications associated with intravenous drug use (IVDU) are increasing. Infective endocarditis (IE) is a serious complication of IVDU, and understanding the characteristics of these patients could aid health systems, clinicians, and patients in the optimization of treatment and prevention of IVDU-IE.

Methods

At a tertiary care hospital in southern New Brunswick, we conducted a retrospective chart review to identify patients with IVDU-IE admitted between January 1, 2013, and December 31, 2017. We collected data related to the epidemiology, microbiology, clinical manifestations, echocardiography, complications during hospital admission, and outcomes.

Results

Forty-two cases of IVDU-IE met inclusion criteria. The rate of IVDU-IE increased from 2.28 per 100,000 population in 2014 to 4.00 in 2017, which, although not statistically significant, reflects patterns in other jurisdictions. Most patients (72.4%) were male, and the mean age was 38.3 (±11.5) years. Most patients (79.3%) injected opioids. The most common clinical sign was fever (90.5%), and Staphylococcus aureus (61.9%) was the most common microorganism. The tricuspid valve was most commonly infected (58.5%), 50% of cases had heart failure as a complication during admission, and 45.2% of cases required valve replacement or repair. The 2-year survival rate after admission for initial IVDU-IE episode was 62.0% (95% confidence interval: 36.5-79.7).

Conclusion

IVDU-IE is common in New Brunswick and may be increasing. Despite the relatively young age of this patient population, IVDU-IE is associated with significant morbidity and mortality. Expanding effective harm reduction and addiction treatment strategies for this cohort is recommended.

Validity of ICD-based algorithms to estimate the prevalence of injection drug use among infective endocarditis hospitalizations in the absence of a reference standard

BACKGROUND

International Classification of Diseases (ICD) code algorithms are routinely used to estimate the frequency of illicit injection drug use (IDU)-associated hospitalizations in administrative health datasets despite a lack of evidence regarding their validity. We aimed to measure the sensitivity and specificity of ICD code algorithms used to estimate the prevalence of current/recent IDU among infective endocarditis (IE) hospitalizations without a reference standard.

METHODS

We reviewed medical records of 321 patients aged 18-64 years old from an urban academic hospital with an IE diagnosis between 2007 and 2017. Diagnostic tests for IDU included self-reported IDU in medical records; a drug use, abuse and dependence (UAD) ICD algorithm; a Hepatitis C Virus (HCV) ICD algorithm; and a combination drug UAD/HCV ICD algorithm. Sensitivity, specificity and the misclassification error (ME)-adjusted IDU prevalence were estimated using Bayesian latent class models.

RESULTS

The combination algorithm had the highest sensitivity and lowest specificity. Sensitivity increased for the drug UAD algorithm in the ICD-10 period compared to the ICD-9 period. The ME-adjusted current/recent IDU prevalence estimated using the drug UAD and HCV algorithms was 23 % (95 % Bayesian credible interval: 16 %, 31 %). The unadjusted prevalence estimate from the drug UAD algorithm underestimated the ME-adjusted prevalence, while the combination algorithm overestimated it.

CONCLUSION

The validity of ICD code algorithms for IDU among IE hospitalizations is imperfect and differs between ICD-9 and ICD-10. Commonly used ICD-based algorithms could lead to substantially biased prevalence estimates in IDU-associated hospitalizations when using administrative health data.

Comparative Effectiveness of Different Treatment Pathways for Opioid Use Disorder

Importance

Although clinical trials demonstrate the superior effectiveness of medication for opioid use disorder (MOUD) compared with nonpharmacologic treatment, national data on the comparative effectiveness of real-world treatment pathways are lacking.

Objective

To examine associations between opioid use disorder (OUD) treatment pathways and overdose and opioid-related acute care use as proxies for OUD recurrence.

Design, Setting, and Participants

This retrospective comparative effectiveness research study assessed deidentified claims from the OptumLabs Data Warehouse from individuals aged 16 years or older with OUD and commercial or Medicare Advantage coverage. Opioid use disorder was identified based on 1 or more inpatient or 2 or more outpatient claims for OUD diagnosis codes within 3 months of each other; 1 or more claims for OUD plus diagnosis codes for opioid-related overdose, injection-related infection, or inpatient detoxification or residential services; or MOUD claims between January 1, 2015, and September 30, 2017. Data analysis was performed from April 1, 2018, to June 30, 2019.

Exposures

One of 6 mutually exclusive treatment pathways, including (1) no treatment, (2) inpatient detoxification or residential services, (3) intensive behavioral health, (4) buprenorphine or methadone, (5) naltrexone, and (6) nonintensive behavioral health.

Main Outcomes and Measures

Opioid-related overdose or serious acute care use during 3 and 12 months after initial treatment.

Results

A total of 40 885 individuals with OUD (mean [SD] age, 47.73 [17.25] years; 22 172 [54.2%] male; 30 332 [74.2%] white) were identified. For OUD treatment, 24 258 (59.3%) received nonintensive behavioral health, 6455 (15.8%) received inpatient detoxification or residential services, 5123 (12.5%) received MOUD treatment with buprenorphine or methadone, 1970 (4.8%) received intensive behavioral health, and 963 (2.4%) received MOUD treatment with naltrexone. During 3-month follow-up, 707 participants (1.7%) experienced an overdose, and 773 (1.9%) had serious opioid-related acute care use. Only treatment with buprenorphine or methadone was associated with a reduced risk of overdose during 3-month (adjusted hazard ratio [AHR], 0.24; 95% CI, 0.14-0.41) and 12-month (AHR, 0.41; 95% CI, 0.31-0.55) follow-up. Treatment with buprenorphine or methadone was also associated with reduction in serious opioid-related acute care use during 3-month (AHR, 0.68; 95% CI, 0.47-0.99) and 12-month (AHR, 0.74; 95% CI, 0.58-0.95) follow-up.

Conclusions and Relevance

Treatment with buprenorphine or methadone was associated with reductions in overdose and serious opioid-related acute care use compared with other treatments. Strategies to address the underuse of MOUD are needed.

Hydromorphone and the risk of infective endocarditis among people who inject drugs: a population-based, retrospective cohort study

BACKGROUND

The incidence of infective endocarditis related to injection drug use is increasing. On the basis of clinical practice and epidemiological and in-vitro data, we postulated that exposure to controlled-release hydromorphone is associated with an increased risk of infective endocarditis among people who inject drugs.

METHODS

We used linked health administrative databases in Ontario, Canada, to assemble a retrospective cohort of adults (aged 18-55 years) who inject drugs for the period of April 1, 2006, to Sept 30, 2015. Cases of infective endocarditis among this cohort were identified using International Classification of Diseases 10 codes. We estimated exposure to hydromorphone and risk of infective endocarditis among this cohort in two ways. First, in a population-level analysis, we identified patients living in regions with high (≥25%) and low (≤15%) hydromorphone prescription rates and, after matching 1:1 on various baseline characteristics, compared their frequency of infective endocarditis. Second, in a patient-level analysis including only those with prescription drug data, we identified those who had filled prescriptions (ie, received the drug from the pharmacy) for controlled-release or immediate-release hydromorphone and, after matching 1:1 on various baseline characteristics, compared their frequency of infective endocarditis with that of patients who had filled prescriptions for other opioids.

RESULTS

Between April 1, 2006, and Sept 30, 2015, 60 529 patients had evidence of injection drug use, 733 (1·2%, 95% CI 1·1-1·3) of whom had infective endocarditis. In the population-level analysis of 32 576 matched patients, we identified 254 (1·6%) admissions with infective endocarditis in regions with high hydromorphone use and 113 (0·7%) admissions in regions with low use (adjusted odds ratio [OR] 2·2, 95% CI 1·8-2·8, p<0·0001). In the patient-level analysis of 3884 matched patients, the frequency of infective endocarditis was higher among patients who filled prescriptions for hydromorphone than among those who filled prescriptions for non-hydromorphone opioids (2·8% [109 patients] vs 1·1% [41 patients]; adjusted OR 2·5, 95% CI 1·8-3·7, p<0·0001). This significant association was seen for controlled-release hydromorphone (3·9% [73 of 1895 patients] vs 1·1% [20 of 1895]; adjusted OR 3·3, 95% CI 2·1-5·6, p<0·0001), but not for immediate-release hydromorphone (1·8% [36 of 1989] vs 1·1% [21 of 1989]; 1·7, 0·9-3·6, p=0·072.

INTERPRETATION

Among people who inject drugs, the risk of infective endocarditis is significantly higher for those exposed to controlled-release hydromorphone than to other opioids. This association might be mediated by the controlled-release mechanism and should be the subject of further investigation.

FUNDING

Ontario Ministry of Health and Long-Term Care, Academic Medical Organization of Southwestern Ontario, Schulich School of Medicine and Dentistry (Western University), and Lawson Health Research Institute.

Recurrent Endocarditis in Persons Who Inject Drugs

Background

Infective endocarditis (IE) is increasing among persons who inject drugs (PWID) and has high morbidity and mortality. Recurrent IE in PWID is not well described.

Methods

This was a retrospective cohort study conducted between February 2007 and March 2016. It included adult inpatients (≥18) at any of 3 tertiary care centers in London, Ontario, with definite IE based on the Modified Duke's Criteria. The objectives were to characterize recurrent IE in PWID, identify risk factors for recurrent IE, identify the frequency of fungal endocarditis, and establish whether fungal infection was associated with higher mortality.

Results

Three hundred ninety patients had endocarditis, with 212/390 in PWID. Sixty-eight of 212 (32%) PWID had a second episode, with 28/212 (12%) having additional recurrences. Second-episode IE was more common in PWID (11/178 [6.2%] vs 68/212 [32.1%]; P < .001). Peripherally inserted central catheter (PICC) line abuse was associated with increased risk of recurrent endocarditis (odds ratio [OR], 1.97; 95% confidence interval [CI], 1.01–3.87; P = .04). In PWID, fungal IE was more common in second episodes than first episodes (1/212 [0.5%] vs 5/68 [7.4%]; P = .004). Additionally, fungal infections were associated with mortality in second-episode IE in PWID with an adjusted OR of 16.49 (95% CI, 1.12–243.17; P = .041). Despite recurrent infection, likely due to continued drug use, there was a low rate of referral to addiction treatment (14/68 [20.6%]).

Conclusions

PWID have a high risk of recurrent endocarditis, particularly in patients who abuse PICC lines. Fungal endocarditis is more common in second-episode endocarditis and is associated with increased mortality. Consideration of empiric antifungal therapy in PWID with IE history and suspected IE should be considered.

A controlled-release oral opioid supports S. aureus survival in injection drug preparation equipment and may increase bacteremia and endocarditis risk

Background

Injection drug use-associated endocarditis (IDUaIE) incidence in Ontario has recently been associated with hydromorphone prescribing rates. Staphylococcus aureus causes the majority of cases of IDUaIE in Ontario and across North America. Hydromorphone controlled-release (Hydromorphone-CR) requires a complex technique for injection and therefore provides multiple opportunities for contamination. Hydromorphone-CR contains several excipients, which could enhance staphylococcal survival and increase risk of contaminating the injectate.

Methods

Used injection drug preparation equipment (cookers/filters) was collected from persons who inject drugs (PWID), rinsed with water, and plated on Mannitol salt agar. Bacterial isolates from bacteremic PWID were used to assess the survival of S. aureus and Streptococcus pyogenes on cookers/filters with Hydromorphone-CR, hydromorphone immediate-release (Hydromorphone-IR) or oxycodone controlled-release (Oxycodone-CR). The solutions spiked with S. aureus were heated and the remaining viable bacteria enumerated.

Results

S. aureus was detected in 12/87 (14%, 95%CI 8–23%) cookers/filters samples used for injection of Hydromorphone-CR. Hydromorphone-CR was the only opioid associated with greater survival of methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) on cookers/filters when compared to sterile water vehicle control. There was a ~2 log reduction in the number of S. aureus that survived when cookers/filters were heated.

Conclusion

14% of all cookers/filters used in the preparation of Hydromorphone-CR were contaminated with S. aureus. Hydromorphone-CR prolongs the survival of MRSA and MSSA in cookers/filters. Heating cookers/filters may be a harm-reduction strategy.