Association between immigration status and total knee arthroplasty outcomes in Ontario, Canada: a population-based matched cohort study

BACKGROUND

Immigrants and refugees face unique challenges navigating the health care system to manage severe arthritis, because of unfamiliarity, lack of awareness of surgical options, or access. The purpose of this study was to assess total knee arthroplasty (TKA) uptake, surgical outcomes, and hospital utilization among immigrants and refugees compared with Canadian-born patients.

METHODS

We included all adults undergoing primary TKA from January 2011 to December 2020 in Ontario. Cohorts were defined as Canadian-born or immigrants and refugees. We assessed change in yearly TKA utilization for trend. We compared differences in 1-year revision, infection rates, 30-day venous thromboembolism (VTE), presentation to emergency department, and hospital readmission between matched Canadian-born and immigrant and refugee groups.

RESULTS

We included 158 031 TKA procedures. A total of 11 973 (7.6%) patients were in the immigrant and refugee group, and 146 058 (92.4%) patients were in the Canadian-born group. The proportion of TKAs in Ontario performed among immigrants and refugees nearly doubled over the 10-year study period (p < 0.001). After matching, immigrants were at relatively lower risk of 1-year revision (0.9% v. 1.6%, p < 0.001), infection (p < 0.001), death (p = 0.004), and surgical complications (p < 0.001). No differences were observed in rates of 30-day VTE or length of hospital stay. Immigrants were more likely to be discharged to rehabilitation (p < 0.001) and less likely to present to the emergency department (p < 0.001) than Canadian-born patients.

CONCLUSION

Compared with Canadian-born patients, immigrants and refugees have favourable surgical outcomes and similar rates of resource utilization after TKA. We observed an underutilization of these procedures in Ontario relative to their proportion of the population. This may reflect differences in perceptions of chronic pain or barriers accessing arthroplasty.

Opioid-related deaths between 2019 and 2021 across 9 Canadian provinces and territories

BACKGROUND

The drug toxicity crisis continues to accelerate across Canada, with rapid increases in opioid-related harms following the onset of the COVID-19 pandemic. We sought to describe trends in the burden of opioid-related deaths across Canada throughout the pandemic, comparing these trends by province or territory, age, and sex.

METHODS

We conducted a repeated cross-sectional analysis of accidental opioid-related deaths between Jan. 1, 2019, and Dec. 31, 2021, across 9 Canadian provinces and territories using aggregated national data. Our primary measure was the burden of premature opioid-related death, measured by potential years of life lost. Our secondary measure was the proportion of all deaths attributable to opioids; we used the Cochrane-Armitage test for trend to compare proportions.

RESULTS

Between 2019 and 2021, the annual number of opioid-related deaths increased from 3007 to 6222 and years of life lost increased from 126 115 to 256 336 (from 3.5 to 7.0 yr of life lost per 1000 population). In 2021, the highest number of years of life lost was among males (181 525 yr) and people aged 30-39 years (87 045 yr). In 2019, we found that 1.7% of all deaths among those younger than 85 years were related to opioids, rising to 3.2% in 2021. Significant increases in the proportion of deaths related to opioids were observed across all age groups (p < 0.001), representing 29.3% and 29.0% of deaths among people aged 20-29 and 30-39 years in 2021, respectively.

INTERPRETATION

Across Canada, the burden of premature opioid-related deaths doubled between 2019 and 2021, representing more than one-quarter of deaths among younger adults. The disproportionate loss of life in this demographic group highlights the critical need for targeted prevention efforts.

Impact of the coronavirus disease 2019 pandemic on equity of access to hip and knee replacements: a population-level study

PURPOSE

The COVID-19 pandemic had innumerable impacts on healthcare delivery. In Canada, this included limitations on inpatient capacity, which resulted in an increased focus on outpatient surgery for non-emergent cases such as joint replacements. The objective of this study was to assess whether the pandemic and the shift towards outpatient surgery had an impact on access to joint replacement for marginalized patients.

METHODS

Data from Ontario's administrative healthcare databases were obtained for all patients undergoing an elective hip or knee replacement between January 1, 2018 and August 31, 2021. All surgeries performed before March 15, 2020 were classified as "pre-COVID," while all procedures performed after that date were classified as "post-COVID." The Ontario Marginalization Index domains were used to analyze proportion of marginalized patients undergoing surgery pre- and post-COVID.

RESULTS

A total of 102,743 patients were included-42,812 hip replacements and 59,931 knee replacements. There was a significant shift towards outpatient surgery during the post-COVID period (1.1% of all cases pre-COVID to 13.2% post-COVID, p < 0.001). In the post-COVID cohort, there were significantly fewer patients from some marginalized groups, as well as fewer patients with certain co-morbidities, such as congestive heart failure and chronic obstructive pulmonary disease.

CONCLUSION

The most important finding of this population-level database study is that, compared to before the COVID-19 pandemic, there has been a change in the profile of patients undergoing hip and knee replacements in Ontario, specifically across a range of indicators. Fewer marginalized patients are undergoing joint replacement surgery since the COVID-19 pandemic. Further monitoring of access to joint replacement surgery is required in order to ensure that surgery is provided to those who are most in need.

Risk of Arterial and Venous Thrombotic Events Among Patients with COVID-19: A Multi-National Collaboration of Regulatory Agencies from Canada, Europe, and United States

Purpose

Few studies have examined how the absolute risk of thromboembolism with COVID-19 has evolved over time across different countries. Researchers from the European Medicines Agency, Health Canada, and the United States (US) Food and Drug Administration established a collaboration to evaluate the absolute risk of arterial (ATE) and venous thromboembolism (VTE) in the 90 days after diagnosis of COVID-19 in the ambulatory (eg, outpatient, emergency department, nursing facility) setting from seven countries across North America (Canada, US) and Europe (England, Germany, Italy, Netherlands, and Spain) within periods before and during COVID-19 vaccine availability.

Patients and Methods

We conducted cohort studies of patients initially diagnosed with COVID-19 in the ambulatory setting from the seven specified countries. Patients were followed for 90 days after COVID-19 diagnosis. The primary outcomes were ATE and VTE over 90 days from diagnosis date. We measured country-level estimates of 90-day absolute risk (with 95% confidence intervals) of ATE and VTE.

Results

The seven cohorts included 1,061,565 patients initially diagnosed with COVID-19 in the ambulatory setting before COVID-19 vaccines were available (through November 2020). The 90-day absolute risk of ATE during this period ranged from 0.11% (0.09-0.13%) in Canada to 1.01% (0.97-1.05%) in the US, and the 90-day absolute risk of VTE ranged from 0.23% (0.21-0.26%) in Canada to 0.84% (0.80-0.89%) in England. The seven cohorts included 3,544,062 patients with COVID-19 during vaccine availability (beginning December 2020). The 90-day absolute risk of ATE during this period ranged from 0.06% (0.06-0.07%) in England to 1.04% (1.01-1.06%) in the US, and the 90-day absolute risk of VTE ranged from 0.25% (0.24-0.26%) in England to 1.02% (0.99-1.04%) in the US.

Conclusion

There was heterogeneity by country in 90-day absolute risk of ATE and VTE after ambulatory COVID-19 diagnosis both before and during COVID-19 vaccine availability.

Estimating the completeness of physician billing claims for diabetes case ascertainment: a multiprovince investigation

INTRODUCTION

Previous research has suggested that how physicians are paid may affect the completeness of billing claims for estimating chronic disease. The purpose of this study is to estimate the completeness of physician billings for diabetes case ascertainment.

METHODS

We used administrative data from eight Canadian provinces covering the period 1 April 2014 to 31 March 2016. The patient cohort was stratified into two mutually exclusive groups based on their physician remuneration type: fee-for-service (FFS), for those paid only on that basis; and non-fee-for-service (NFFS). Using diabetes prescription drug data as our reference data source, we evaluated whether completeness of disease case ascertainment varied with payment type. Diabetes incidence rates were then adjusted for completeness of ascertainment.

RESULTS

The cohort comprised 86 110 patients. Overall, equal proportions received their diabetes medications from FFS and NFFS physicians. Overall, physician payment method had little impact upon the percentage of missed diabetes cases (FFS, 14.8%; NFFS, 12.2%). However, the difference in missed cases between FFS and NFFS varied widely by province, ranging from -1.0% in Nova Scotia to 29.9% in Newfoundland and Labrador. The difference between the observed and adjusted disease incidence rates also varied by province, ranging from 22% in Prince Edward Island to 4% in Nova Scotia.

CONCLUSION

The difference in the loss of cases by physician remuneration method varied across jurisdictions. This loss may contribute to an underestimation of disease incidence. The method we used could be applied to other chronic diseases for which drug therapy could serve as reference data source.

Health care utilization and outcomes of patients seen by virtual urgent care versus in-person emergency department care

BACKGROUND

Virtual urgent care (VUC) is intended to support diversion of patients with low-acuity complaints and reduce the need for in-person emergency department visits. We aimed to describe subsequent health care utilization and outcomes of patients who used VUC compared with similar patients who had an in-person emergency department visit.

METHODS

We used patient-level encounter data that were prospectively collected for patients using VUC services provided by 14 pilot programs in Ontario, Canada. We linked the data to provincial administrative databases to identify subsequent 30-day health care utilization and outcomes. We defined 2 subgroups of VUC users; those with a documented prompt referral to an emergency department by a VUC provider, and those without. We matched patients in each cohort to an equal number of patients presenting to an emergency department in person, based on encounter date, medical concern and the logit of a propensity score. For the subgroup of patients not promptly referred to an emergency department, we matched patients to those who were seen in an emergency department and then discharged home.

RESULTS

Of the 19 595 patient VUC visits linked to administrative data, we matched 2129 patients promptly referred to the emergency department by a VUC provider to patients presenting to the emergency department in person. Index visit hospital admissions (9.4% v. 8.7%), 30-day emergency department visits (17.0% v. 17.5%), and hospital admissions (12.9% v. 11.0%) were similar between the groups. We matched 14 179 patients who were seen by a VUC provider with no documented referral to the emergency department. Patients seen by VUC were more likely to have a subsequent in-person emergency department visit within 72 hours (13.7% v. 7.0%), 7 days (16.5% v. 10.3%) and 30 days (21.9% v. 17.9%), but hospital admissions were similar within 72 hours (1.1% v. 1.3%), and higher within 30 days for patients who were discharged home from the emergency department (2.6% v. 3.4%).

INTERPRETATION

The impact of the provincial VUC pilot program on subsequent health care utilization was limited. There is a need to better understand the inherent limitations of virtual care and ensure future virtual providers have timely access to in-person outpatient resources, to prevent subsequent emergency department visits.

Prescription ranitidine use and population exposure in 6 Canadian provinces, 1996 to 2019: a serial cross-sectional analysis

BACKGROUND

Ranitidine was the most prescribed histamine-2 receptor antagonist (H2RA) in Canada when recalled in 2019 because of potential carcinogenicity. We sought to compare geographic and temporal patterns in use of prescription ranitidine and 3 other HRAs and estimated population exposure to ranitidine in 6 provinces between 1996 and 2019.

METHODS

This population-based serial cross-sectional study used prescription claims for H2RAs dispensed from community pharmacies in Nova Scotia, Ontario, Manitoba, Saskatchewan, Alberta and British Columbia. We estimated the period prevalence of ranitidine use per 100 population by province, age category and sex. We estimated exposure to ranitidine between 2015 and 2019 using defined daily doses (DDDs).

RESULTS

Overall, 2.4 million ranitidine prescriptions were dispensed to patients aged 65 years and older, and 1.7 million were dispensed to younger adults. Among older adults, the median period prevalence of ranitidine use among females was 16% (interquartile range [IQR] 13%-27%) higher than among males. Among younger adults, the median prevalence was 50% (IQR 37%-70%) higher among females. Among older adults, between 1996 and 1999, use was highest in Nova Scotia (33%) and Ontario (30%), lower in the prairies (Manitoba [18%], Saskatchewan [26%], Alberta [17%]) and lowest in BC (11%). By 2015-2019, use of ranitidine among older adults dropped by at least 50% in all provinces except BC. We estimate that at least 142 million DDDs of prescribed ranitidine were consumed annually in 6 provinces (2015-2019).

INTERPRETATION

Over the 24-year period in 6 provinces, patients aged 65 years and older were dispensed 2.4 million prescriptions of ranitidine and younger adults were dispensed 1.7 million prescriptions of ranitidine. These estimates of ranitidine exposure can be used for planning studies of cancer risk and identifying target populations for cancer surveillance.

Validity of diagnoses of SARS-CoV-2 infection in Canadian administrative health data: a multiprovince, population-based cohort study

BACKGROUND

Accurate coding of diagnoses of SARS-CoV-2 infection in administrative data benefits population-based studies about the epidemiology, treatment and outcomes of COVID-19. We describe the validity of diagnoses of SARS-CoV-2 infection recorded in hospital discharge abstracts, emergency department records and outpatient physician service claims from 3 Canadian provinces.

METHODS

In this cohort study, population-based inpatient, emergency department and outpatient records were linked to SARS-CoV-2 polymerase chain reaction (PCR; reference standard) test results from British Columbia, Manitoba and Ontario for Apr. 1, 2020, to Mar. 31, 2021. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of diagnoses of SARS-CoV-2 infection were estimated for each quarter in the study period, overall and by province, age group and sex.

RESULTS

Our study encompassed more than 13 million SARS-CoV-2 PCR test results. Specificity and NPV of diagnoses of SARS-CoV-2 infection were consistently high (i.e., most estimates were > 95%). Overall sensitivity estimates were 86.2%, 60.4% and 20.3% in the first quarter for inpatient, emergency department and outpatient cohorts, and 66.2%, 47.5% and 25.0% in the last quarter, respectively. For inpatients, overall PPV estimates ranged from 50.0% to 66.4%. For emergency department patients, overall PPV estimates were 76.9% and 68.3% in the first and last quarters, respectively. For outpatients, PPV estimates were 6.8% and 29.1% in the first and last quarters, respectively.

INTERPRETATION

We found variations in the validity of diagnoses for SARS-CoV-2 infection recorded in different health care settings, geographic areas and over time. Our multiprovince validation study provides evidence about the potential use of inpatient and emergency department records as an alternative to population-based laboratory data for identification of patients with SARS-CoV-2 infection, but does not support the use of outpatient claims for this purpose.

Prevalence and predictors for being unscreened for diabetic retinopathy: a population-based study over a decade

OBJECTIVE

To determine the population-level predictors for being unscreened for diabetic retinopathy (DR) among individuals with diabetes in a developed country.

DESIGN

A retrospective population-based repeated-cross-sectional study.

PARTICIPANTS

All individuals with diabetes (types 1 and 2) aged ≥20 years in the universal health care system in Ontario were identified in the 2011-2013 and 2017-2019 time periods.

METHODS

The Mantel-Haenszel test was used for the relative risk (RR) comparison of subcategories stratified by the 2 cross-sectional time periods.

RESULTS

A total of 1 145 645 and 1 346 578 individuals with diabetes were identified in 2011-2013 and 2017-2019, respectively. The proportion of patients unscreened for DR declined very slightly from 35% (n = 405 967) in 2011-2013 to 34% (n = 455 027) in 2017-2019 of the population with diabetes (RR = 0.967; 95% CI, 0.964-0.9693; p < 0.0001). Young adults aged 20-39 years of age had the highest proportion of unscreened patients (62% and 58% in 2011-2013 and 2017-2019, respectively). Additionally, those who had a lower income quintile (RR = 1.039; 95% CI, 1.036-1.044; p < 0.0001), were recent immigrants (RR = 1.286; 95% CI, 1.280-1.293; p < 0.0001), lived in urban areas (RR = 1.149; 95% CI, 1.145-1.154; p < 0.0001), had a mental health history (RR = 1.117; 95% CI, 1.112-1.122; p < 0.0001), or lacked a connection to a primary care provider (RR = 1.656; 95% CI, 1.644-1.668; p < 0.0001) had a higher risk of being unscreened.

CONCLUSIONS

This population-based study suggests that over 1 decade, 33% of individuals with diabetes are unscreened for DR, and young age, low income, immigration, residing in a large city, mental health illness, and no primary care access are the main predictors.

Prescription of oxycodone versus codeine after childbirth and risk of persistent opioid use: a population-based cohort study

BACKGROUND

Oxycodone is increasingly prescribed for postpartum analgesia in lieu of codeine owing to concerns regarding the neonatal safety of codeine during lactation. We examined whether initiation of oxycodone after delivery was associated with an increased risk of persistent opioid use relative to initiation of codeine.

METHODS

We conducted a population-based cohort study of people who filled a prescription for either codeine or oxycodone within 7 days of discharge from hospital after delivery between Sept. 1, 2012, and June 30, 2020. The primary outcome was persistent opioid use, defined as 1 or more additional prescriptions for an opioid within 90 days of the first postpartum prescription and 1 or more additional prescriptions in the 91 to 365 days thereafter. We used inverse probability of treatment weighting to assess the risk of persistent postpartum opioid use, comparing people who initiated oxycodone with those who initiated codeine.

RESULTS

Over the 8-year study period, we identified 70 607 people who filled an opioid prescription within 7 days of discharge from hospital: 21 308 (30.2%) received codeine and 49 299 (69.8%) oxycodone. Compared with people who filled a prescription for codeine, receipt of oxycodone was not associated with persistent opioid use (relative risk [RR] 1.04, 95% confidence interval [CI] 0.91-1.20). We found an association between a prescription for oxycodone and persistent use after vaginal delivery (RR 1.63, 95% CI 1.31-2.03), but not after cesarean delivery (RR 0.85, 95% CI 0.73-1.00).

INTERPRETATION

Initiation of oxycodone (v. codeine) was not associated with an increased risk of persistent opioid use, except after vaginal delivery.

Trends in Opioid Toxicity-Related Deaths in the US Before and After the Start of the COVID-19 Pandemic, 2011-2021

Importance

Opioid-related harms constitute a major public health crisis in the US, and this crisis has worsened during the COVID-19 pandemic.

Objectives

To characterize the societal burden of unintentional opioid-related deaths in the US and describe changing mortality patterns during the COVID-19 pandemic.

Design, Setting, and Participants

A serial cross-sectional study examined all unintentional opioid-related deaths in the US, evaluated annually from calendar years 2011 to 2021.

Main Outcomes and Measures

The public health burden of opioid toxicity-related deaths was estimated in 2 ways. First, the proportion of all deaths that were attributable to unintentional opioid toxicity by year (2011, 2013, 2015, 2017, 2019, and 2021) and age group (15-19, 20-29, 30-39, 40-49, 50-59, and 60-74 years) were calculated, using age-specific estimates of all-cause mortality as the denominator. Second, the total years of life lost (YLL) due to unintentional opioid toxicity was estimated, overall and by sex and age group, for each year studied.

Results

Among the 422 605 unintentional deaths due to opioid toxicity between 2011 and 2021, the median age of the individuals was 39 (IQR, 30-51) years, and 69.7% were male. The number of unintentional deaths due to opioid toxicity increased 289% over the study period, from 19 395 (2011) to 75 477 (2021). Similarly, the percentage of all deaths that were attributed to opioid toxicity increased from 1.8% in 2011 to 4.5% in 2021. By 2021, opioid toxicity was responsible for 10.2% of all deaths among those aged 15 to 19 years, 21.7% of deaths among those aged 20 to 29 years, and 21.0% of deaths among those aged 30 to 39 years. The YLL due to opioid toxicity increased 276% over the study period, from 777 597 in 2011 to 2 922 497 in 2021. While YLL plateaued between 2017 (7.0 YLL per 1000) and 2019 (7.2 YLL per 1000), it increased by 62.9% between 2019 and 2021 coincident with the COVID-19 pandemic, reaching 11.7 YLL per 1000 population. This relative increase was similar across all age groups and sexes with the exception of those aged 15 to 19 years, in whom the YLL nearly tripled, from 1.5 to 3.9 YLL per 1000 population.

Conclusions and Relevance

In this cross-sectional study, deaths due to opioid toxicity increased substantially during the COVID-19 pandemic. By 2021, 1 of every 22 deaths in the US was attributable to unintentional opioid toxicity, underscoring the urgent need to support people at risk of substance-related harm, particularly men, younger adults, and adolescents.

Residual Risk of Breast Cancer After Bariatric Surgery

Importance

Excess adiposity confers higher risk of breast cancer for women. For women who have lost substantial weight, it is unclear whether previous obesity confers residual increased baseline risk of breast cancer compared with peers without obesity.

Objectives

To determine whether there is a residual risk of breast cancer due to prior obesity among patients who undergo bariatric surgery.

Design, Setting, and Participants

Retrospective matched cohort study of 69 260 women with index date between January 1, 2010, and December 31, 2016. Patients were followed up for 5 years after bariatric surgery or index date. Population-based clinical and administrative data from multiple databases in Ontario, Canada, were used to match a cohort of women who underwent bariatric surgery for obesity (baseline body mass index [BMI] ≥35 with comorbid conditions or BMI ≥40) to women without a history of bariatric surgery according to age and breast cancer screening history. Nonsurgical controls were divided into 4 BMI categories (<25, 25-29, 30-34, and ≥35). Data were analyzed on October 21, 2021.

Exposures

Weight loss via bariatric surgery.

Main Outcomes and Measures

Residual hazard of breast cancer after washout periods of 1, 2, and 5 years. Comparisons were made between the surgical and nonsurgical cohorts overall and within each of the BMI subgroups.

Results

In total, 69 260 women were included in the analysis, with 13 852 women in each of the 5 study cohorts. The mean (SD) age was 45.1 (10.9) years. In the postsurgical cohort vs the overall nonsurgical cohort (n = 55 408), there was an increased hazard for incident breast cancer in the nonsurgical group after washout periods of 1 year (hazard ratio [HR], 1.40 [95% CI, 1.18-1.67]), 2 years (HR, 1.31 [95% CI, 1.12-1.53]), and 5 years (HR, 1.38 [95% CI, 1.21-1.58]). When the postsurgical cohort was compared with the nonsurgical cohort with BMI less than 25, the hazard of incident breast cancer was not significantly different regardless of the washout period, whereas there was a reduced hazard for incident breast cancer among postsurgical patients compared with nonsurgical patients in all high BMI categories (BMI ≥25).

Conclusions and Relevance

Findings suggest that bariatric surgery was associated with a reduced risk of developing breast cancer for women with prior obesity equivalent to that of a woman with a BMI less than 25 and a lower risk when compared with all groups with BMI greater than or equal to 25.

Up-to-date on cancer screening among Ontario patients seen by walk-in clinic physicians: A retrospective cohort study

Walk-in clinics are typically viewed as high-volume locations for managing acute issues but also may serve as a location for primary care, including cancer screening, for patients without a family physician. In this population-based cohort study, we compared breast, cervical and colorectal cancer screening up-to-date status for people living in the Canadian province of Ontario who were formally enrolled to a family physician versus those not enrolled but who had at least one encounter with a walk-in clinic physician in the previous year. Using provincial administrative databases, we created two mutually exclusive groups: i) those who were formally enrolled to a family physician, ii) those who were not enrolled but had at least one visit with a walk-in clinic physician from April 1, 2019 to March 31, 2020. We compared up to date status for three cancer screenings as of April 1, 2020 among screen-eligible people. We found that people who were not enrolled and had seen a walk-in clinic physician in the previous year consistently were less likely to be up to date on cancer screening than Ontarians who were formally enrolled with a family physician (46.1% vs. 67.4% for breast, 45.8% vs. 67.4% for cervical, 49.5% vs. 73.1% for colorectal). They were also more likely to be foreign-born and to live in structurally marginalized neighbourhoods. New methods are needed to enable screening for people who are reliant on walk-in clinics and to address the urgent need in Ontario for more primary care providers who deliver comprehensive, longitudinal care.

Hydrochlorothiazide use and risk of keratinocyte carcinoma and melanoma: A multi-site population-based cohort study

BACKGROUND

The association between hydrochlorothiazide (HCTZ) and skin cancer remains controversial.

OBJECTIVE

To determine whether HCTZ is associated with an increased risk of skin cancer compared with angiotensin-converting enzyme inhibitors (ACEIs) and calcium channel blockers (CCBs).

METHODS

Two new-user, active comparator cohorts were assembled using six Canadian databases. Site-specific hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using standardized morbidity ratio weighted Cox proportional hazard models and pooled using random-effects meta-analysis.

RESULTS

HCTZ was not associated with an overall increased risk of keratinocyte carcinoma compared with ACEIs or CCBs, although increased risks were observed with longer durations (≥10 years; HR: 1.12; 95% CI: 1.03-1.21) and higher cumulative doses (≥100,000 mg; HR: 1.49; 95% CI: 1.27-1.76). For melanoma, there was no association with ACEIs, but a 32% increased risk with CCBs (crude incidence rates: 64.2 vs. 58.4 per 100,000 person-years; HR: 1.32; 95% CI: 1.19-1.46; estimated number needed to harm at 5 years of follow-up: 1,627 patients), with increased risks with longer durations and cumulative doses.

LIMITATIONS

Residual confounding due to the observational design.

CONCLUSIONS

Increased risks of keratinocyte carcinoma and melanoma were observed with longer durations of use and higher cumulative doses of HCTZ.

Maternal opioid treatment after delivery and risk of adverse infant outcomes: population based cohort study

OBJECTIVE

To examine whether maternal opioid treatment after delivery is associated with an increased risk of adverse infant outcomes.

DESIGN

Population based cohort study.

SETTING

Ontario, Canada.

PARTICIPANTS

865 691 mother-infant pairs discharged from hospital alive within seven days of delivery from 1 September 2012 to 31 March 2020. Each mother who filled an opioid prescription within seven days of discharge was propensity score matched to a mother who did not.

MAIN OUTCOME MEASURES

The primary outcome was hospital readmission of infants for any reason within 30 days of their mother filling an opioid prescription (index date). Infant related secondary outcomes were any emergency department visit, hospital admission for all cause injury, admission to a neonatal intensive care unit, admission with resuscitation or assisted ventilation, and all cause death.

RESULTS

85 675 mothers (99.8% of the 85 852 mothers prescribed an opioid) who filled an opioid prescription within seven days of discharge after delivery were propensity score matched to 85 675 mothers who did not. Of the infants admitted to hospital within 30 days, 2962 (3.5%) were born to mothers who filled an opioid prescription compared with 3038 (3.5%) born to mothers who did not. Infants of mothers who were prescribed an opioid were no more likely to be admitted to hospital for any reason than infants of mothers who were not prescribed an opioid (hazard ratio 0.98, 95% confidence interval 0.93 to 1.03) and marginally more likely to be taken to an emergency department in the subsequent 30 days (1.04, 1.01 to 1.08), but no differences were found for any other adverse infant outcomes and there were no infant deaths.

CONCLUSIONS

Findings from this study suggest no association between maternal opioid prescription after delivery and adverse infant outcomes, including death.

Walk-in clinic patient characteristics and utilization patterns in Ontario, Canada: a cross-sectional study

BACKGROUND

Walk-in clinics are common in North America and are designed to provide acute episodic care without an appointment. We sought to describe a sample of walk-in clinic patients in Ontario, Canada, which is a setting with high levels of primary care attachment.

METHODS

We performed a cross-sectional study using health administrative data from 2019. We compared the sociodemographic characteristics and health care utilization patterns of patients attending 1 of 72 walk-in clinics with those of the general Ontario population. We examined the subset of patients who were enrolled with a family physician and compared walk-in clinic visits to family physician visits.

RESULTS

Our study found that 562 781 patients made 1 148 151 visits to the included walk-in clinics. Most (70%) patients who attended a walk-in clinic had an enrolling family physician. Walk-in clinic patients were younger (mean age 36 yr v. 41 yr, standardized mean difference [SMD] 0.24), yet had greater health care utilization (moderate and high use group 74% v. 65%, SMD 0.20) than the general Ontario population. Among enrolled Ontarians, walk-in patients had more comorbidities (moderate and high count 50% v. 45%, SMD 0.10), lived farther from their enrolling physician (median 8 km v. 6 km, SMD 0.21) and saw their enrolling physician less in the previous year (any visit 67% v. 80%, SMD 0.30). Walk-in encounters happened more often after hours (16% v. 9%, SMD 0.20) and on weekends (18% v. 5%, SMD 0.45). Walk-in clinics were more often within 3 km of patients' homes than enrolling physicians' offices (0 to < 3 km: 32% v. 22%, SMD 0.21).

INTERPRETATION

Our findings suggest that proximity of walk-in clinics and after-hours access may be contributing to walk-in clinic use among patients enrolled with a family physician. These findings have implications for policy development to improve the integration of walk-in clinics and longitudinal primary care.

Changing patterns of opioid initiation for pain management in Ontario, Canada: A population-based cross-sectional study

INTRODUCTION

The recent publication of a national guideline and quality standards in Canada have provided clinicians with new, evidence-based recommendations on safe, appropriate opioid use. We sought to characterize how well opioid initiation practices aligned with these recommendations before and following their release.

METHODS

We conducted a population-based study among people initiating opioids prior to the release of national guidelines (April 2015-March 2016; fiscal year [FY] 2015) and in the most recent year available (January-December 2019) in Ontario, Canada. We used linked administrative claims data to ascertain the apparent indication for opioid therapy, and characterized the initial daily dose (milligrams morphine or equivalent; MME) and prescription duration for each indication.

RESULTS

In FY2015, 653,885 individuals commenced opioids, compared to 571,652 in 2019. Over time, there were small overall reductions in the prevalence of initial daily doses exceeding 50MME (23.9% vs. 20.1%) and durations exceeding 7 days (17.4% vs. 14.8%); but the magnitude of the reductions varied widely by indication. The prevalence of high dose (>50MME) initial prescriptions reduced significantly across all indications, with the exception of dentist-prescribed opioids (13.6% vs. 12.1% above 50MME). In contrast, there was little change in initial durations exceeding 7 days across most indications, with the exception of some surgical indications (e.g. common excision; 9.3% vs. 6.2%) and among those in palliative care (35.2% vs. 29.2%).

CONCLUSION

Despite some modest reductions in initiation of high dose and long duration prescription opioids between 2015 and 2019, clinical practice is highly variable, with opioid prescribing practices influenced by clinical indication. These findings may help identify medical specialties well-suited to targeted interventions to promote safer opioid prescribing.

Patterns of antiemetic medication use during pregnancy: A multi-country retrospective cohort study

OBJECTIVE

To compare patterns in use of different antiemetics during pregnancy in Canada, the United Kingdom, and the United States, between 2002 and 2014.

METHODS

We constructed population-based cohorts of pregnant women using administrative healthcare data from five Canadian provinces (Alberta, British Columbia, Manitoba, Ontario, and Saskatchewan), the Clinical Practice Research Datalink from the United Kingdom, and the IBM MarketScan Research Databases from the United States. We included pregnancies ending in live births, stillbirth, spontaneous abortion, or induced abortion. We determined maternal use of antiemetics from pharmacy claims in Canada and the United States and from prescriptions in the United Kingdom.

RESULTS

The most common outcome of 3 848 734 included pregnancies (started 2002-2014) was live birth (66.7% of all pregnancies) followed by spontaneous abortion (20.2%). Use of antiemetics during pregnancy increased over time in all three countries. Canada had the highest prevalence of use of prescription antiemetics during pregnancy (17.7% of pregnancies overall, 13.2% of pregnancies in 2002, and 18.9% in 2014), followed by the United States (14.0% overall, 8.9% in 2007, and 18.1% in 2014), and the United Kingdom (5.0% overall, 4.2% in 2002, and 6.5% in 2014). Besides use of antiemetic drugs being considerably lower in the United Kingdom, the increase in its use over time was more modest. The most commonly used antiemetic was combination doxylamine/pyridoxine in Canada (95.2% of pregnancies treated with antiemetics), ondansetron in the United States (72.2%), and prochlorperazine in the United Kingdom (63.5%).

CONCLUSIONS

In this large cohort study, we observed an overall increase in antiemetic use during pregnancy, and patterns of use varied across jurisdictions. Continued monitoring of antiemetic use and further research are warranted to better understand the reasons for differences in use of these medications and to assess their benefit-risk profile in this population.

Duration of use and outcomes among people with opioid use disorder initiating methadone and buprenorphine in Ontario: a population-based propensity-score matched cohort study

AIMS

To characterize comparative risks and benefits of methadone versus buprenorphine/naloxone in a contemporary cohort where the unregulated drug supply is dominated by fentanyl.

DESIGN, SETTING AND PARTICIPANTS

Population-based propensity-score matched cohort study conducted in Ontario, Canada among people aged 18+ initiating opioid agonist therapy (OAT) for an opioid use disorder between October 2016 and December 2018 (n = 18 880).

INTERVENTION

Initiation of methadone versus buprenorphine/naloxone.

MEASUREMENTS

The primary outcome was opioid overdose (fatal and non-fatal) while on treatment, with secondary outcomes including opioid overdose (first 30 days of treatment), treatment discontinuation, health-care interactions related to treatment of opioid use disorder, receiving a weekly supply of take-home doses and opioid overdose within 30 days of treatment discontinuation. Outcomes were assessed over 1 year.

FINDINGS

Overall, 7517 people initiating buprenorphine were matched to an equal number of methadone-treated individuals. Risk of opioid overdose while on treatment [hazard ratio (HR) = 0.50; 95% confidence interval (CI) = 0.37-0.68] or within the first 30 days of treatment (HR = 0.51, 95% CI = 0.31-0.85) was lower among buprenorphine recipients compared to methadone recipients. In secondary analyses, people initiating buprenorphine had a higher risk of treatment discontinuation within the first year (median time to discontinuation 104 versus 265 days, HR = 1.43, 95% CI = 1.37-1.49), had lower rates of health-care interactions for OUD (186.4 versus 254.3 per person-year; rate ratio = 0.73; 95% CI = 0.72-0.75), and a higher rate of receiving weekly take-home doses (HR = 2.33; 95% CI = 2.20-2.46). Overdose rates in the period following OAT discontinuation were higher than those observed while on treatment, but did not differ significantly by OAT type.

CONCLUSIONS

Although treatment retention is higher among methadone recipients, overdose risk is also elevated compared to buprenorphine recipients. These findings demonstrate the benefits of any OAT on avoidance of overdose, particularly following treatment discontinuation and with the increasingly unpredictable drug supply in North America.

Survival after surgery for spinal metastases: a population-based study

Background:

There are limited published data on population estimates of survival after spinal surgery for metastatic disease. We performed a population-based study to evaluate survival and complications among patients with cancer who underwent surgery for spinal metastases in Ontario, Canada, between 2006 and 2016.

Methods:

We used health administrative databases to identify all patients who underwent surgery for spinal metastases in Ontario between Jan. 1, 2006, and Dec. 31, 2016. We assessed overall survival, mortality rates according to primary cancer lesion and complications after surgery. We contrast the results to those for a comparable cohort from 1991 to 1998.

Results:

A total of 2646 patients (1194 women [45.1%]; mean age 62.5 yr [standard deviation 12.2 yr]) were identified. The median survival time was 236 (interquartile range 84–740) days. Mortality was highest for patients with melanoma, upper gastrointestinal cancer and lung cancer, with 50% dying within 90 days of surgery. The longest median survival times were observed for primary cancers of the thyroid (906 d) and breast (644 d), and myeloma (830 d). Overall 90-day and 1-year mortality rates were 29% and 59%, respectively.

Conclusion:

We identified differential survivorship based on primary tumour type and a shift in the distribution of operations performed for specific primary cancers over the past 2 decades in Ontario. Overall reductions in mortality associated with this shift in treatment may reflect the use of adjuvant therapies and more personalized treatment approaches.

Healthcare utilization and costs for musculoskeletal disorders in Ontario, Canada

OBJECTIVE

To examine the magnitude and costs of ambulatory primary and specialist physician care and hospital service use for musculoskeletal disorders (MSDs) in Canada's largest province, Ontario.

METHODS

Administrative health databases were analyzed for fiscal year 2013-2014 for adults 18+ years, including data on physician services, emergency department (ED) visits and hospitalizations. ICD diagnostic codes were used to identify MSD services. A validated algorithm was used to estimate direct medical costs. Person visit rates and numbers of persons and visits were tabulated by care setting, age and sex, and physician specialty. Data were examined for all MSDs combined as well as specific diagnostic groupings.

RESULTS

Overall, 3.1 million adult Ontarians (28.5%) made 8 million outpatient physician visits associated with MSDs. These included 5.6 million primary care visits. MSDs accounted for 560,000, 12.3%, of all adult ED visits. Total costs for MSD-related care were $1.6 billion, with 12.6% of costs attributed to primary care, 9.2% to specialist care, 8.6% to ED care, 8.5% to day surgery and 61.2% of total costs associated with inpatient hospitalizations. Costs due to arthritis accounted for 40% of total MSD care costs ($639 million). MSD-related imaging costs were $169 million. Including these costs yields a total estimate of $1.8 billion for all MSDs combined.

CONCLUSION

MSDs place a significant and costly burden on the health care system. Health system planning needs to consider the large and escalating demand for care to reduce both the individual and population burden.

Pivoting data and analytic capacity to support Ontario's COVID-19 response

Introduction

Health care systems have faced unprecedented challenges due to the COVID-19 pandemic. Access to timely population-based data has been vital to informing public health policy and practice.

Methods

We describe how ICES, an independent not-for-profit research and analytic institute in Ontario, Canada, pivoted existing research infrastructure and engaged health system stakeholders to provide near real-time population-based data and analytics to support Ontario's COVID-19 pandemic response.

Results

Since April 2020, ICES provided the Ontario COVID-19 Provincial Command Table and public health partners with regular and ad hoc reports on SARS-CoV-2 testing and COVID-19 vaccine coverage. These reports: 1) helped identify congregate care/shared living settings that needed testing and prevention efforts early in the pandemic; 2) provided early indications of inequities in testing and infection in marginalized neighbourhoods, including areas with higher proportions of immigrants and visible minorities; 3) identified areas with high test positivity, which helped Public Health Units target and evaluate prevention efforts; and 4) contributed to altering the province's COVID-19 vaccine roll-out strategy to target high-risk neighbourhoods and helping Public Health Units and community organizations plan local vaccination programs. In addition, ICES is a key component of the Ontario Health Data Platform, which provides scientists with data access to conduct COVID-19 research and analyses.

Discussion and Conclusion

ICES was well-positioned to provide rapid analyses for decision-makers to respond to the evolving public health emergency, and continues to contribute to Ontario's pandemic response by providing timely, relevant reports to health system stakeholders and facilitating data access for externally-funded COVID-19 research.

Impact of changes in opioid funding and clinical policies on rapid tapering of opioids in Ontario, Canada

ABSTRACT

Reports have emerged of abrupt tapering among recipients of long-term prescription opioids to conform new prescribing guidelines. We conducted a population-based, repeated cross-sectional time-series study among very high-dose (≥200 MME) opioid recipients in Ontario, Canada, to examine changes in the monthly prevalence of rapid tapering from 2014 to 2018, defined as recipients experiencing either a ≥50% reduction in daily doses or abrupt discontinuation sustained for 30 days. Interventional autoregressive integrated moving average models were used to test for significant changes following key guidelines and drug policies and programs. A sensitivity analysis examined rapid tapering sustained for 90 days. The monthly prevalence of rapid tapering events was stable from January 2014 to September 2016 (average monthly prevalence: 1.4%) but increased from 1.4% in October 2016 to 1.8% in April 2017 (P = 0.001), coincident with Ontario's Fentanyl Patch-for-Patch Return Program implementation. Transient spikes in the prevalence of rapid tapering also occurred 2 months after Ontario's delisting of publicly funded high-strength opioids and the release of updated Canadian Opioid Prescribing Guideline for Chronic Pain, reaching 2.3% in March 2017 and July 2017, respectively. However, this prevalence decreased to 1.2% in December 2018 (P < 0.0001). Although the prevalence of abrupt opioid discontinuation was lower, similar trends were observed. Our sensitivity analysis examining long-lasting rapid tapering found similar trends but lower prevalence, with no changes in complete discontinuation. These temporary increases in rapid tapering events highlight the need for improved communication and evidence-based resources for prescribers to minimize negative consequences of evolving policies and guidelines.

Incidence and Outcomes Associated With Clostridioides difficile Infection in Solid Organ Transplant Recipients

IMPORTANCE

Little is known about the incidence and outcomes of Clostridioides difficile infection (CDI) in solid organ transplant (SOT) recipients.

OBJECTIVE

To estimate the CDI incidence and outcomes in SOT recipients.

DESIGN, SETTING, AND PARTICIPANTS

A population-based cohort study was conducted using administrative health care data for all Ontario, Canada, residents who received organ allografts from April 1, 2003, to December 31, 2017; March 31, 2020, was the end of the study period.

MAIN OUTCOMES AND MEASURES

The primary outcome was hospital admission with CDI diagnosis. The secondary outcomes included all-cause death, intensive care unit admission, acute kidney injury requiring dialysis, and fulminant CDI comprising any of the following: toxic megacolon, ileus, perforation, or colectomy. The association between short- vs long-term mortality (ie, death occurring within or after 90 days post-CDI) and the following variables was evaluated: age, sex, Deyo-Charlson Comorbidity Index, SOT type, early- vs late-onset CDI, fulminant CDI, intensive care unit admission, and acute kidney injury requiring acute dialysis.

RESULTS

Overall, 10 724 SOT recipients (6901 [64.4%] men; median age, 54 [IQR, 44-62] years) were eligible. Kidney transplant was the most common SOT type (6453 [60.2%]). The median follow-up time was 5.0 (IQR, 2.3-8.8) years, resulting in 61 987 person-years of follow-up. A total of 726 patients (6.8%) were hospitalized with CDI. The 1-year CDI incidence significantly increased in annual cohorts (ie, from 23.1; 95% CI, 12.8-41.8 per 1000 person-years in 2004 to 46.7; 95% CI, 35.0-62.3 per 1000 person-years in 2017; P = .001). Clostridioides difficile was associated with a 16.8% rate (n = 122) of 90-day mortality. In patients who underwent kidney transplant, CDI was typically late-onset (median interval, 2.2; IQR, 0.4-6.0 years) compared with recipients of other organs. Acute kidney injury requiring dialysis was significantly associated with short-term (adjusted odds ratio [aOR], 1.86; 95% CI, 1.07-3.26) and long-term (adjusted hazard ratio [aHR], 1.89; 95% CI, 1.29-2.78) mortality, and late-onset CDI was also significantly associated with a greater risk of short-term (aOR, 4.26; 95% CI, 2.51-7.22) and long-term (aHR, 2.49; 95% CI, 1.78-3.49) mortality.

CONCLUSIONS AND RELEVANCE

In this study, increasing CDI trends in annual cohorts of SOT recipients were observed. Posttransplant CDI was associated with mortality, and late-onset CDI was associated with a greater risk of death than early-onset CDI. These findings suggest that preventive strategies should not be limited to the initial months following transplantation. Comprehensive therapeutic approaches targeting acute kidney injury risk factors in SOT recipients may reduce short- and long-term post-CDI mortality.

Supporting policy and practice in Ontario through ICES' Applied Health Research Question (AHRQ) program

ICES upholds a strong reputation for generating high-quality evidence to inform policy and practice through its collaborations with a broad range of health system stakeholders including government policymakers and healthcare providers including clinicians. Supported by the Ontario Ministry of Health and Ministry of Long-Term Care, the ICES Applied Health Research Question (AHRQ) Program leverages the data holdings and, scientific and clinical expertise to generate evidence tailored to the information needs of requestors. This paper outlines the approach, process, strengths, challenges and the resulting influence and impact to the healthcare landscape in Ontario.

Projected impact of biosimilar substitution policies on drug use and costs in Ontario, Canada: a cross-sectional time series analysis

BACKGROUND

Several Canadian provinces have introduced reimbursement policies mandating substitution of innovator biologics with lower-cost biosimilars. We estimated the number of patients affected and cost implications if such policy changes were to be implemented in Ontario, Canada.

METHODS

We conducted a cross-sectional time series analysis of Ontarians dispensed publicly funded biologics indicated for inflammatory diseases (rheumatic conditions, inflammatory bowel disease: infliximab, etanercept, adalimumab) between January 2018 and December 2019, and forecasted trends to Dec. 31, 2020. The primary source of data was pharmacy claims data for all biologics reimbursed by the public drug program. We modelled the number of patients affected and government expenditures (in nominal Canadian dollars) of several biosimilar policy options, including mandatory nonmedical biosimilar substitution, substitution in new users, introduction of a biosimilar for adalimumab, and price negotiations. In a secondary analysis, we included insulin glargine.

RESULTS

In 2018, 14 089 individuals were prescribed a publicly funded biologic for inflammatory diseases. A mandatory nonmedical biosimilar substitution would potentially have affected 7209 patients and saved $238.6 million from 2018 to 2020. A new-user substitution would have affected 757 patients and saved $34.2 million. If an adalimumab biosimilar were to become available, 12 928 patients would be affected by a mandatory nonmedical substitution and the 3-year savings would increase to $645.9 million (all biosimilars priced at 25% of innovator biologics). Finally, an expanded nonmedical substitution policy including insulin glargine would affect 115 895 patients and save $288.7 million (not including adalimumab).

INTERPRETATION

Policies designed to curb rising costs of biologics can have substantially different effects on patients and government expenditures. Such analyses warrant careful consideration of the balance between cost savings and effects on patients.

Rates of rebleeding, thrombosis and mortality associated with resumption of anticoagulant therapy after anticoagulant-related bleeding

BACKGROUND:

Data on resuming oral anticoagulants (OACs) after bleeding are primarily from studies involving patients given warfarin, with few data on direct OACs (DOACs). We aimed to characterize prescribing patterns for OACs after OAC-related bleeding and compare the rates of bleeding, thrombosis and mortality in patients who resumed either type of OAC with those who did not.

METHODS:

We conducted a population-based cohort study of adults aged 66 years or older who were admitted to hospital for bleeding while receiving OACs from Apr. 1, 2012, to Mar. 31, 2017, using linked administrative health databases from Ontario. We used competing risk methods to calculate cause-specific adjusted hazard ratios (HRs) for thrombosis, bleeding and mortality with resumption of OACs adjusted as a time-varying covariate. We determined time to OAC resumption using the Kaplan–Meier method.

RESULTS:

We included 6793 patients with gastrointestinal (n = 4297, 63.3%), intracranial (n = 805, 11.9%) or other bleeding (n = 1691, 25.0%). At cohort entry, 3874 patients (57.0%) were prescribed warfarin and 2919 patients (43.0%) were prescribed a DOAC. The most common indication for OAC was atrial fibrillation (n = 5557, 81.8%), followed by venous thromboembolism (n = 1367, 20.1%). Oral anticoagulants were resumed in 4792 patients (70.5%) within 365 days of the index bleed. The median time to resumption was 46 (interquartile range 6–550) days. We found that resuming OAC was associated with reduced rates of thrombosis (adjusted HR 0.60, 95% confidence interval [CI] 0.50–0.72) and mortality (adjusted HR 0.54, 95% CI 0.48–0.60), and an increased rate of rebleeding (adjusted HR 1.88, 95% CI 1.64–2.17).

INTERPRETATION:

We found that resuming OAC is associated with a reduction in thrombosis and mortality but an increase in bleeding. Randomized controlled trials that evaluate the net benefit of strategies for resumption of OAC after a bleeding event are warranted.

Comparison of 4-Year Health Care Expenditures Associated With Roux-en-Y Gastric Bypass vs Sleeve Gastrectomy

IMPORTANCE

Data on the long-term health care expenditures associated with bariatric surgery consisting of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy are lacking.

OBJECTIVE

To compare 4-year health care expenditures after RYGB vs sleeve gastrectomy, identify factors independently associated with 4-year health care expenditures, and compare the procedures in terms of subsequent hospitalizations, bariatric procedures, and all-cause mortality.

DESIGN, SETTING, AND PARTICIPANTS

In this propensity score-matched cohort study, all residents of Ontario, Canada, who underwent publicly funded surgery with RYGB (n = 6301) or sleeve gastrectomy (n = 926) from March 1, 2010, to March 31, 2015, and consented to participate in the Ontario Bariatric Registry were eligible for the study. Follow-up was completed on March 31, 2019, and data were analyzed from May 5, 2020, to May 20, 2021.

INTERVENTIONS

RYGB and sleeve gastrectomy.

MAIN OUTCOMES AND MEASURES

Publicly funded health care expenditures, subsequent hospitalizations, bariatric procedures, and mortality during the 4 years after RYGB or sleeve gastrectomy.

RESULTS

The 1:1 matched study cohorts consisted of 1624 patients (812 per cohort) with a mean (SD) age of 48.0 (10.6) years, and 1242 women (76.5%). The mean body mass index (calculated as weight in kilograms divided by height in square meters) was 51.9 (8.3) for the RYGB cohort and 51.9 (8.9) for the sleeve gastrectomy cohort. The 4-year cumulative costs were not statistically significantly different between RYGB and sleeve gastrectomy (mean [SD], $33 682 [$31 169] vs $33 948 [$32 633], respectively; P = .86). Having a history of coronary artery disease was associated with a 35% increase in overall health care expenditures; chronic kidney disease, a 54% increase; and mental health admissions, a 67% increase. There were no statistically significant differences in all-cause mortality between RYGB and sleeve gastrectomy (1.5% vs 2.2%, respectively; P = .26) or the total number of hospitalizations (754 vs 669, respectively; P = .11) during the 4-year follow-up period. However, nonelective hospitalizations occurred more frequently with RYGB vs sleeve gastrectomy (472 vs 339, respectively; P = .002). Roux-en-Y gastric bypass was associated with relatively fewer subsequent bariatric procedures during the 4-year follow-up period (9 vs 40, respectively; P < .001).

CONCLUSIONS AND RELEVANCE

In this Canadian population-based study, key results indicated that 4-year health care expenditures, all-cause mortality, and number of hospital admissions associated with RYGB did not significantly differ from those for sleeve gastrectomy. The rate of subsequent bariatric surgery was lower with RYGB. This study identified important patient-level drivers of health care expenditures that need to be further investigated.

Association of Surgical Experience With Risk of Complication in Total Hip Arthroplasty Among Patients With Severe Obesity

IMPORTANCE

Severe obesity is a risk factor for major early complications after total hip arthroplasty (THA).

OBJECTIVE

To determine the association between surgeon experience with THA in patients with severe obesity and risk of complications.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective population-based cohort study was performed in Ontario, Canada, from April 1, 2007, to March 31, 2017, with data analysis performed from March 2020 to January 2021. A cohort of patients who received a primary THA for osteoarthritis and who also had severe obesity (body mass index [calculated as weight in kilograms divided by height in meters squared] ≥40) at the time of surgery was defined. These patients were identified using the Canadian Institute for Health Information Discharge Abstract Database and physician claims from the Ontario Health Insurance Plan. Generalized estimating equations were used to determine the association between overall THA and severe obesity-specific THA surgeon volume and the occurrence of complications after controlling for potential confounders. The study hypothesized that surgeon experience specific to patients with severe obesity could further reduce the risk of complications.

EXPOSURES

Primary THA.

MAIN OUTCOMES AND MEASURES

Complications were considered as a composite outcome (revision, infection requiring surgery, or dislocation requiring reduction), within 1 year of surgery. This was defined before the study, as was the study hypothesis.

RESULTS

A total of 4781 eligible patients was identified. The median age was 63 (interquartile range [IQR], 56-69) years, and 3050 patients (63.8%) were women. Overall, 186 patients (3.9%) experienced a surgical complication within 1 year of surgery. The median overall THA surgeon volume was 70 (IQR, 46-106) cases/y, whereas the median obesity-specific surgeon volume was 5 (IQR, 2-9) cases/y. After controlling for patient and hospital factors, greater obesity-specific THA surgeon volume (adjusted odds ratio per additional 10 cases, 0.65 [95% CI, 0.47-0.89]; P = .007), but not greater overall THA surgeon volume (adjusted odds ratio per 10 additional cases, 0.97 [95% CI, 0.93-1.02]; P = .24), was associated with a reduced risk of complication.

CONCLUSIONS AND RELEVANCE

Increased surgeon experience performing THA in patients with severe obesity was associated with fewer major surgical complications. These findings suggest that surgeon experience is required to mitigate the unique anatomical challenges posed by surgery in patients with severe obesity. Referral pathways for patients with severe obesity to surgeons with high obesity-specific THA volume should be considered.

Derivation and validation of predictors of oral anticoagulant-related adverse events in seniors transitioning from hospital to home

INTRODUCTION

Oral anticoagulant (OAC)-related adverse events are high post-hospitalization. We planned to develop and validate a prediction model for OAC-related harm within 30 days of hospitalization.

METHODS

We undertook a population-based study of adults aged ≥66 years who were discharged from hospital on an OAC from September 2010 to March 2015 in Ontario, Canada. The primary outcome was a composite of time to first hospitalization or emergency department visit for a hemorrhagic or thromboembolic event, or mortality within 30 days of hospital discharge. Cox proportional hazards regression was used to build the model.

RESULTS

We included 120,721 patients of which 5423 experienced the outcome. Most patients were aged ≥75 years (59.5%) and were female (55.6%). Sixty percent of the cohort had a follow-up visit with a healthcare provider within 7 days of discharge. Patients discharged on a direct acting OAC versus warfarin (apixaban: Hazard Ratio [HR] 0.82, 95% confidence interval [CI] 0.71-0.94; dabigatran: HR 0.73, 95% CI 0.63-0.84; rivaroxaban: HR 0.79, 95% CI 0.71-0.88), were prevalent users of the dispensed OAC versus incident users (HR 0.82, 95% CI 0.69-0.96), had a joint replacement in the past 35 days (HR 0.40, 95% CI 0.33-0.50) or major surgery during index hospital stay (HR 0.69, 95% CI 0.60-0.80) had a lower risk for the outcome. The Cox model was stable with acceptable discrimination but poor goodness-of-fit.

CONCLUSIONS

A model for OAC-related harm in the early post-discharge period was developed. External validation studies are required to understand the model's poor calibration.

The Role of a Resilient Information Infrastructure in COVID-19 Vaccine Uptake in Ontario

The COVID-19 pandemic has highlighted the need for a robust and nimble public health data infrastructure. ICES - a government-sponsored, independent, non-profit research institute in Ontario, Canada - functions as a key component of a resilient information infrastructure and an enabler of data co-production, contributing to Ontario's response to the COVID-19 pandemic as part of a learning health system. Linked data on the cumulative incidence of infection and vaccination at the neighbourhood level revealed disparate uptake between areas with low versus high risk of COVID-19. These data were leveraged by the government, service providers, media and the public to inform a more efficient and equitable vaccination strategy.

Effects of hospital funding reform on wait times for hip fracture surgery: a population-based interrupted time-series analysis

Background

Health care funding reforms are being used worldwide to improve system performance but may invoke unintended consequences. We assessed the effects of introducing a targeted hospital funding model, based on fixed price and volume, for hip fractures. We hypothesized the policy change was associated with reduction in wait times for hip fracture surgery, increase in wait times for non-hip fracture surgery, and increase in the incidence of after-hours hip fracture surgery.

Methods

This was a population-based, interrupted time series analysis of 49,097 surgeries for hip fractures, 10,474 for ankle fractures, 1,594 for tibial plateau fractures, and 40,898 for appendectomy at all hospitals in Ontario, Canada between April 2012 and March 2017. We used segmented regression analysis of interrupted monthly time series data to evaluate the impact of funding reform enacted April 1, 2014 on wait time for hip fracture repair (from hospital presentation to surgery) and after-hours provision of surgery (occurring between 1700 and 0700 h). To assess potential adverse consequences of the reform, we also evaluated two control procedures, ankle and tibial plateau fracture surgery. Appendectomy served as a non-orthopedic tracer for assessment of secular trends.

Results

The difference (95 % confidence interval) between the actual mean wait time and the predicted rate had the policy change not occurred was − 0.46 h (-3.94 h, 3.03 h) for hip fractures, 1.46 h (-3.58 h, 6.50 h) for ankle fractures, -3.22 h (-39.39 h, 32.95 h) for tibial plateau fractures, and 0.33 h (-0.57 h, 1.24 h) for appendectomy (Figure 1; Table 3). The difference (95 % confidence interval) between the actual and predicted percentage of surgeries performed after-hours − 0.90 % (-3.91 %, 2.11 %) for hip fractures, -3.54 % (-11.25 %, 4.16 %) for ankle fractures, 7.09 % (-7.97 %, 22.14 %) for tibial plateau fractures, and 1.07 % (-2.45 %, 4.59 %) for appendectomy.

Conclusions

We found no significant effects of a targeted hospital funding model based on fixed price and volume on wait times or the provision of after-hours surgery. Other approaches for improving hip fracture wait times may be worth pursuing instead of funding reform.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06601-2.

Inequities in access to primary care among opioid recipients in Ontario, Canada: A population-based cohort study

BACKGROUND

Stigma and high-care needs can present barriers to the provision of high-quality primary care for people with opioid use disorder (OUD) and those prescribed opioids for chronic pain. We explored the likelihood of securing a new primary care provider (PCP) among people with varying histories of opioid use who had recently lost access to their PCP.

METHODS AND FINDINGS

We conducted a retrospective cohort study using linked administrative data among residents of Ontario, Canada whose enrolment with a physician practicing in a primary care enrolment model (PEM) was terminated between January 2016 and December 2017. We assigned individuals to 3 groups based upon their opioid use on the date enrolment ended: long-term opioid pain therapy (OPT), opioid agonist therapy (OAT), or no opioid. We fit multivariable models assessing the primary outcome of primary care reattachment within 1 year, adjusting for demographic characteristics, clinical comorbidities, and health services utilization. Secondary outcomes included rates of emergency department (ED) visits and opioid toxicity events. Among 154,970 Ontarians who lost their PCP, 1,727 (1.1%) were OAT recipients, 3,644 (2.4%) were receiving long-term OPT, and 149,599 (96.5%) had no recent prescription opioid exposure. In general, OAT recipients were younger (median age 36) than those receiving long-term OPT (59 years) and those with no recent prescription opioid exposure (44 years). In all exposure groups, the majority of individuals had their enrolment terminated by their physician (range 78.1% to 88.8%). In the primary analysis, as compared to those not receiving opioids, OAT recipients were significantly less likely to find a PCP within 1 year (adjusted hazard ratio [aHR] 0.55, 95% confidence interval [CI] 0.50 to 0.61, p < 0.0001). We observed no significant difference between long-term OPT and opioid unexposed individuals (aHR 0.96; 95% CI 0.92 to 1.01, p = 0.12). In our secondary analysis comparing the period of PCP loss to the year prior, we found that rates of ED visits were elevated among people not receiving opioids (adjusted rate ratio (aRR) 1.20, 95% CI 1.18 to 1.22, p < 0.0001) and people receiving long-term OPT (aRR 1.37, 95% CI 1.28 to 1.48, p < 0.0001). We found no such increase among OAT recipients, and no significant increase in opioid toxicity events in the period following provider loss for any exposure group. The main limitation of our findings relates to their generalizability outside of PEMs and in jurisdictions with different financial incentives incorporated into primary care provision.

CONCLUSIONS

In this study, we observed gaps in access to primary care among people who receive prescription opioids, particularly among OAT recipients. Ongoing efforts are needed to address the stigma, discrimination, and financial disincentives that may introduce barriers to the healthcare system, and to facilitate access to high-quality, consistent primary care services for chronic pain patients and those with OUD.

Dental Opioid Prescription Characteristics and the Risk of New, Persistent Use

INTRODUCTION

Dentists are a common source of opioid exposure. This study investigates the association between initial dental opioid prescription characteristics and subsequent persistent use and examines the rate of opioid overdose after initiation.

METHODS

A retrospective cohort study was conducted among Ontario residents who were dispensed an initial opioid prescription originating from a dentist between October 2014 and September 2018 (data were analyzed in October 2019-May 2020). Exposures were characterized on the basis of the average daily dose in milligram morphine equivalents and the duration and formulation (long versus short acting) of the initial prescription. New, persistent use was defined as ≥1 opioid prescription within 90 days and another within 91-365 days after the initial prescription. The rate of an opioid overdose within 90 days after initiation was examined.

RESULTS

Among 786,125 Ontarians who initiated a dentist-prescribed opioid, 34,880 (4.4%) developed persistent use, whereas 140 (0.72 per 1,000 person-years) had evidence of an overdose within 90 days. People dispensed an initial daily dose >90 milligram morphine equivalents (n=5,644, 0.7%) had significantly greater odds of persistence (AOR=1.20, 95% CI=1.07, 1.34) than those dispensed ≤20 milligram morphine equivalents (n=179,884, 22.9%). Persistence was also significantly associated with receiving longer prescription durations and a long-acting opioid on initiation.

CONCLUSIONS

Among people who initiated a dentist-prescribed opioid, 1 in 23 experienced persistent use, and persistence was associated with the characteristics of the prescription. Prescribing lower doses, prescribing for shorter durations, and avoiding long-acting formulations may be an opportunity to lessen the risk of persistent opioid use.

Trends in Postpartum Opioid Prescribing: A Time Series Analysis

Opioids are commonly prescribed following childbirth, but data are lacking on trends in postpartum opioid prescribing over time. We examined whether a highly publicized 2006 case report questioning the safety of codeine during lactation was associated with changes in postpartum opioid prescribing. We conducted a cross-sectional time series analysis of all publicly funded prescriptions for opioids to postpartum women in Ontario, Canada, from April 1, 2000, to March 31, 2017. The intervention was the publication of a case report in 2006 attributing the death of a breastfeeding neonate to maternal codeine use. The primary outcome was the rate of opioid prescribing to postpartum women. Among postpartum women eligible for prescription drug coverage, 17.5% filled an opioid prescription in the third quarter of 2006 (immediately prior to the intervention), with codeine representing 89.8% of all prescriptions. By the fourth quarter of 2010, only 12.2% of postpartum women filled an opioid prescription, representing a decline of 30% (P < 0.01), with codeine representing 71.9% of all prescriptions. During this period, we observed sizeable relative increases in the proportion of opioid prescriptions filled for morphine, hydromorphone, and oxycodone. By 2017, among women prescribed opioids post partum, 39.0% filled a prescription for codeine, while the remainder filled prescriptions for oxycodone (18.6%), morphine (25.5%), and hydromorphone (16.9%). A highly publicized case report questioning the safety of maternal codeine use during breastfeeding was associated with significant changes in opioid prescribing to postpartum women, including a decline in overall opioid prescribing and a shift from codeine to stronger opioids.

Health care costs of rheumatoid arthritis: A longitudinal population study

Quantifying the contribution of rheumatoid arthritis to the acquisition of subsequent health care costs is an emerging focus of the rheumatologic community and payers of health care. Our objective was to determine the healthcare costs before and after diagnosis of rheumatoid arthritis (RA) from the public payer's perspective. The study design was a longitudinal observational administrative data-based cohort with RA cases from Ontario Canada (n = 104,933) and two control groups, matched 1:1 on year of cohort entry from 2001 to 2016. The first control group was matched on age, sex and calendar year of cohort entry (diagnosis year for those with RA); the second group added medical history to the match before RA diagnosis year. The main exposure was new onset RA. The secondary exposure was calendar year of RA diagnosis to compare attributable costs over the study observation window. Main outcomes were health care costs in 2015 Canadian dollars, overall and by cost category. We used attribution methods to classify costs into those associated with RA, those associated with comorbidities, and age/sex-related underlying costs. Health care costs associated with RA increased up to the year of diagnosis, where they reached $8,591: $4,142 in RA associated costs; $1,242 in RA comorbidity associated costs; and $3,207 in underlying costs. In the eighth-year post diagnosis, the RA costs declined to $2,567 while the RA comorbidity associated costs remained relatively constant at $1,142, and the underlying age/sex related cost increased to $4,426. RA patients had lower costs when diagnosed in later calendar years. Our results suggest a large proportion of disease related health care costs are a result of costs associated with RA comorbidities, which may appear many years before diagnosis.

Bariatric Surgery and Cardiovascular Outcomes in Patients With Obesity and Cardiovascular Disease:: A Population-Based Retrospective Cohort Study

BACKGROUND

Bariatric surgery has been shown to significantly reduce cardiovascular risk factors. However, whether surgery can reduce major adverse cardiovascular events (MACE), especially in patients with established cardiovascular disease, remains poorly understood. The present study aims to determine the association between bariatric surgery and MACE among patients with cardiovascular disease and severe obesity.

METHODS

This was a propensity score-matched cohort study using province-wide multiple-linked administrative databases in Ontario, Canada. Patients with previous ischemic heart disease or heart failure who received bariatric surgery were matched on age, sex, heart failure history, and a propensity score to similar controls from a primary care medical record database in a 1:1 ratio. The primary outcome was the incidence of extended MACE (first occurrence of all-cause mortality, myocardial infarction, coronary revascularization, cerebrovascular events, and heart failure hospitalization). Secondary outcome included 3-component MACE (myocardial infarction, ischemic stroke, and all-cause mortality). Outcomes were evaluated through a combination of matching via propensity score and subsequent multivariable adjustment.

RESULTS

A total of 2638 patients (n=1319 in each group) were included, with a median follow-up time of 4.6 years. The primary outcome occurred in 11.5% (151/1319) of the surgery group and 19.6% (259/1319) of the controls (adjusted hazard ratio [HR], 0.58 [95% CI, 0.48-0.71]; P<0.001). The association was notable for those with heart failure (HR, 0.44 [95% CI, 0.31-0.62]; P<0.001; absolute risk difference, 19.3% [95% CI, 12.0%-26.7%]) and in those with ischemic heart disease (HR, 0.60 [95% CI, 0.48-0.74]; P<0.001; absolute risk difference, 7.5% [95% CI, 4.7%-10.5%]). Surgery was also associated with a lower incidence of the secondary outcome (HR, 0.66 [95% CI, 0.52-0.84]; P=0.001) and cardiovascular mortality (HR, 0.35 [95% CI, 0.15-0.80]; P=0.001).

CONCLUSIONS

Bariatric surgery was associated with a lower incidence of MACE in patients with cardiovascular disease and obesity. These findings require confirmation by a large-scale randomized trial.

Association Between Bariatric Surgery and Major Adverse Diabetes Outcomes in Patients With Diabetes and Obesity

IMPORTANCE

There are high-quality randomized clinical trial data demonstrating the effect of bariatric surgery on type 2 diabetes remission, but these studies are not powered to study mortality in this patient group. Large observational studies are warranted to study the association of bariatric surgery with mortality in patients with type 2 diabetes.

OBJECTIVE

To determine the association between bariatric surgery and all-cause mortality among patients with type 2 diabetes and severe obesity.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, population-based matched cohort study included patients with type 2 diabetes and body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) 35 or greater who underwent bariatric surgery from January 2010 to December 2016 in Ontario, Canada. Multiple linked administrative databases were used to define confounders, including age, baseline BMI, sex, comorbidities, duration of diabetes diagnosis, health care utilization, socioeconomic status, smoking status, substance abuse, cancer screening, and psychiatric history. Potential controls were identified from a primary care electronic medical record database. Data were analyzed in 2020.

EXPOSURE

Bariatric surgery (gastric bypass and sleeve gastrectomy) and nonsurgical management of obesity provided by the primary care physician.

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause mortality. Secondary outcomes were cause-specific mortality and nonfatal morbidities. Groups were compared through a multivariable Cox proportional Hazards model.

RESULTS

A total of 6910 patients (mean [SD] age at baseline, 52.04 [9.45] years; 4950 [71.6%] women) were included, with 3455 patients who underwent bariatric surgery and 3455 match controls and a median (interquartile range) follow-up time of 4.6 (3.22-6.35) years. In the surgery group, 83 patients (2.4%) died, compared with 178 individuals (5.2%) in the control group (hazard ratio [HR] 0.53 [95% CI, 0.41-0.69]; P < .001). Bariatric surgery was associated with a 68% lower cardiovascular mortality (HR, 0.32 [95% CI, 0.15-0.66]; P = .002) and a 34% lower rate of composite cardiac events (HR, 0.68 [95% CI, 0.55-0.85]; P < .001). Risk of nonfatal renal events was also 42% lower in the surgical group compared with the control group (HR, 0.58 [95% CI, 0.35-0.95], P = .03). Of the groups that had the highest absolute benefit associated with bariatric surgery, men had an absolute risk reduction (ARR) of 3.7% (95% CI, 1.7%-5.7%), individuals with more than 15 years of diabetes had an ARR of 4.3% (95% CI, 0.8%-7.8%), and individuals aged 55 years or older had an ARR of 4.7% (95% CI, 3.0%-6.4%).

CONCLUSIONS AND RELEVANCE

These findings suggest that bariatric surgery was associated with reduced all-cause mortality and diabetes-specific cardiac and renal outcomes in patients with type 2 diabetes and severe obesity.

Off-label postpartum use of domperidone in Canada: a multidatabase cohort study

BACKGROUND

Trends in off-label postpartum use of domperidone and the impact of safety advisories on its use remain unknown. Our objectives were to describe postpartum use of domperidone in Canada, to evaluate the impact of Health Canada advisories on prescribing patterns, and to describe the association between domperidone use and a composite end point of sudden cardiac death or ventricular tachycardia (VT) among postpartum patients.

METHODS

We conducted a multidatabase cohort study involving pregnant patients with live births between 2004 and 2017 using administrative health databases from 5 Canadian provinces (British Columbia, Alberta, Saskatchewan, Manitoba and Ontario). We excluded patients with less than 1 year of prepregnancy database history and with approved indications for domperidone. We assessed domperidone use in the 6 months postpartum and the impact of the 2012 and 2015 Health Canada advisories on prescribing via interrupted time series analysis. We estimated crude rates of VT and sudden cardiac death.

RESULTS

We included 1 190 987 live births. Mean maternal age was 28.6 (standard error 0.6) years. Domperidone use increased over time, from 7% in 2003-2005 to 12% in 2009-2011, when it plateaued. The 2012 advisory was followed by a drop in use and a reduction in slope, and the 2015 advisory had a more modest impact. Crude analysis suggests that domperidone may be associated with increased VT or sudden cardiac death (0.74 v. 0.37 per 10 000 person-years; difference per 10 000 person-years: 0.37, 95% confidence interval -0.67 to 1.41).

INTERPRETATION

Postpartum domperidone use increased between 2004 and 2017, with prescribing attenuated after Health Canada advisories and a very low absolute rate of VT or sudden cardiac death. These findings suggest that Health Canada advisories affected prescribing; any potential increase in VT or sudden cardiac death with use of domperidone is small and could not be confirmed in this large study STUDY REGISTRATION: ClinicalTrials.gov, no. NCT04024865.

Comparison of Pregnancy Outcomes of Patients Treated With Ondansetron vs Alternative Antiemetic Medications in a Multinational, Population-Based Cohort

IMPORTANCE

Ondansetron is frequently used to treat nausea and vomiting during pregnancy. Although some studies reported important safety signals, few studies have been sufficiently large to assess rare pregnancy outcomes.

OBJECTIVE

To study the association between ondansetron exposure during pregnancy and the risks of spontaneous abortion, stillbirth, and major congenital malformations.

DESIGN, SETTING, AND PARTICIPANTS

This is a cohort study conducted in 3 countries, with a meta-analysis. Participants included women and girls aged 12 to 55 years who experienced spontaneous abortion, induced abortion, stillbirth, or live birth between April 2002 and March 2016, as recorded in administrative data from 5 Canadian provinces (British Columbia, Alberta, Saskatchewan, Manitoba, and Ontario), the US IBM MarketScan Research Databases, and the UK Clinical Practice Research Datalink. The statistical analysis was completed in October 2020.

EXPOSURES

Exposure to ondansetron during pregnancy was compared with exposure to other commonly used antiemetics to minimize confounding by indication.

MAIN OUTCOMES AND MEASURES

The primary outcome was fetal death, defined as either spontaneous abortion or stillbirth. Secondary outcomes were the 2 components of the primary outcome and major congenital malformations identified during the year after a live birth. Adjusted hazard ratios were estimated using Cox proportional hazards models with time-dependent drug exposures and were adjusted using high-dimensional propensity scores. For major congenital malformations, adjusted odds ratios were estimated from logistic models. Site-level results were pooled using random-effects meta-analysis. Sensitivity analyses considered second-line antiemetic exposure and exposure specifically during 4 to 10 weeks of gestation.

RESULTS

Data from 456 963 pregnancies were included in this study of fetal death (249 787 [54.7%] in Canada, 197 913 [43.3%] in the US, and 9263 [2.0%] in the UK; maternal age, ≤24 years, 93 201 patients [20.4%]; 25-29 years, 149 117 patients [32.6%]; 30-34 years, 142 442 patients [31.2%]; and ≥35 years, 72 203 patients [15.8%]). Fetal death occurred in 12 907 (7.9%) of 163 810 pregnancies exposed to ondansetron, and 17 476 (5.7%) of 306 766 pregnancies exposed to other antiemetics. The adjusted hazard ratios were 0.91 (95% CI, 0.67-1.23) for fetal death with time-dependent ondansetron exposure during pregnancy, 0.82 (95% CI, 0.64-1.04) for spontaneous abortion, and 0.97 (95% CI, 0.79-1.20) for stillbirth. For major congenital malformations, the estimated odds ratio was 1.06 (95% CI, 0.91-1.22). Results of sensitivity analyses were generally consistent with those of the primary analyses.

CONCLUSIONS AND RELEVANCE

In this large, multicenter cohort study, there was no association between ondansetron exposure during pregnancy and increased risk of fetal death, spontaneous abortion, stillbirth, or major congenital malformations compared with exposure to other antiemetic drugs.

Analysis of the relationship between surgeon procedure volume and complications after total knee arthroplasty using a propensity-matched cohort study

Objectives

This study aimed to identify a threshold in annual surgeon volume associated with increased risk of revision (for any cause) and deep infection requiring surgery following primary elective total knee arthroplasty (TKA).

Design

A propensity score matched cohort study.

Setting

Ontario, Canada.

Participants

169 713 persons who received a primary TKA between 2002 and 2016, with 3-year postoperative follow-up.

Main outcome measures

Revision arthroplasty (for any cause), and the occurrence of deep surgical infection requiring surgery.

Results

Based on restricted cubic spline analysis, the threshold for increased probability of revision and deep infection requiring surgery was <70 cases/year. After matching of 51 658 TKA recipients from surgeons performing <70 cases/year to TKA recipients from surgeons with greater than 70 cases/year, patients in the former group had a higher rate of revision (for any cause, 2.23% (95% Confidence Interval (CI) 1.39 to 3.07) vs 1.70% (95% CI 0.85 to 2.55); Hazard Ratio (HR) 1.33, 95% CI 1.21 to 1.47, p<0.0001) and deep infection requiring surgery (1.29% (95% CI 0.44 to 2.14) vs 1.09% (95% CI 0.24 to 1.94); HR 1.33, 95% CI 1.17 to 1.51, p<0.0001).

Conclusions

For primary TKA recipients, cases performed by surgeons who had performed fewer than 70 TKAs in the year prior to the index TKA were at 31% increased relative risk of revision (for any cause), and 18% increased relative risk for deep surgical infection requiring surgery, at 3-year follow-up.

Prevalence of winter migration to warmer destinations among Ontarians ("snowbirds") and patterns of their use of health care services: a population-based analysis

BACKGROUND

Older Canadians frequently migrate to warmer destinations for the winter season (snowbirds). Our aim was to examine the prevalence of migration to warmer destinations among Ontarians, and to compare the characteristics and use of health care services of snowbirds to those of older Ontarians who did not migrate for the winter.

METHODS

We conducted a population-based analysis using health administrative databases from Ontario. We compiled 10 seasonal cohorts (2009/10 to 2018/19) of adults aged 65 or more who filled a travel supply of medications under the Ontario Drug Benefits program (snowbirds) between September and January (snowbird season). We calculated the seasonal prevalence of snowbirds per 100 Ontarians aged 65 or more. We matched each snowbird in the 2018/19 season to 2 nonsnowbirds on age and sex, and compared their characteristics and patterns of use of government-funded health care services.

RESULTS

Over the 10-year period, 53 431 to 70 863 Ontarians aged 65 or more were identified as snowbirds (seasonal prevalence 2.6%-3.3%). Compared to nonsnowbirds, snowbirds were more likely to be recent migrants, live in higher-income neighbourhoods, have fewer comorbidities and make more visits to primary care physicians. From January to March 2019, snowbirds accessed government-funded health care services for a median of 0 days (interquartile range [IQR] 0-1 d), compared to 4 days (IQR 2-8 d) among nonsnowbirds.

INTERPRETATION

About 3% of older Ontarians migrate to warmer destinations for the winter each season. Since few access health care services in Ontario from January to March, researchers are encouraged to consider the snowbird population and the impact of their absence on evaluations that assume continuous observation.

Adverse event rates associated with oral anticoagulant treatment early versus later after hospital discharge in older adults: a retrospective population-based cohort study

BACKGROUND

Oral anticoagulants are commonly used high-risk medications, but little is known about their safety in transition from hospital to home. Our objective was to measure the rates of hemorrhage and thromboembolic events among older adults receiving oral anticoagulant treatment early after hospital discharge compared to later.

METHODS

We conducted a retrospective population-based cohort study among Ontario residents aged 66 years or more who started, continued or resumed oral anticoagulant therapy at hospital discharge between September 2010 and March 2015. We calculated the rates of hemorrhage and thromboembolic events requiring hospital admission or an emergency department visit over a 1-year follow-up period, stratified by the first 30 days after discharge and the remainder of the year. We used multivariable regression models, adjusting for covariates, to estimate the effect of sex, prevalent versus incident use, and switching anticoagulants on events.

RESULTS

A total of 123 139 patients (68 408 women [55.6%]; mean age 78.2 yr) were included. About one-quarter (32 563 [26.4%]) had a Charlson Comorbidity Index score of 2 or higher. The rates of hemorrhage and thromboembolic events per 100 person-years were highest during the first 30 days after hospital discharge (25.8, 95% CI 24.8-26.8 and 19.3, 95% CI 18.4-20.2, respectively), falling to 15.7 (95% CI 15.3-16.1) and 6.9 (95% CI 6.6-7.1), respectively, during the subsequent 11 months. Multivariable analysis showed that patients whose anticoagulant was switched in hospital and men had more hemorrhages and thromboembolic events in follow-up.

INTERPRETATION

The first few weeks following hospital discharge represent a very high-risk period for adverse events related to oral anticoagulant treatment among older adults. The results support an intervention trial addressing anticoagulation management in the early postdischarge period.

Evaluation of Rheumatology Workforce Supply Changes in Ontario, Canada, from 2000 to 2030

Rheumatology workforces are increasingly challenged by too few physicians in face of the growing burden of rheumatic and musculoskeletal diseases (RMDs). Rheumatology is one of the most frequent non-surgical specialty referrals and has the longest wait times for subspecialists. We used a population-based approach to describe changes in the rheumatology workforce, patient volumes and geographic variation in the supply of and access to rheumatologists, in Ontario, Canada, between 2000 and 2019, and projected changes in supply by 2030. Over time, we observed greater feminization of the workforce and increasing age of workforce members. We identified a large regional variation in rheumatology supply. Fewer new patients are seen annually, which likely contributes to increasing wait times and reduced access to care. Strategies and policies to raise the critical mass and improve regional distribution of supply to effectively provide rheumatology care and support the healthcare delivery of patients with RMDs are needed.

Impact of preoperative echocardiography on surgical delays and outcomes among adults with hip fracture

AIMS

Echocardiography is commonly used in hip fracture patients to evaluate perioperative cardiac risk. However, echocardiography that delays surgical repair may be harmful. The objective of this study was to compare surgical wait times, mortality, length of stay (LOS), and healthcare costs for similar hip fracture patients evaluated with and without preoperative echocardiograms.

METHODS

A population-based, matched cohort study of all hip fracture patients (aged over 45 years) in Ontario, Canada between 2009 and 2014 was conducted. The primary exposure was preoperative echocardiography (occurring between hospital admission and surgery). Mortality rates, surgical wait times, postoperative LOS, and medical costs (expressed as 2013$ CAN) up to one year postoperatively were assessed after propensity-score matching.

RESULTS

A total of 2,354 of 42,230 (5.6%) eligible hip fracture patients received a preoperative echocardiogram during the study period. Echocardiography ordering practices varied among hospitals, ranging from 0% to 23.0% of hip fracture patients at different hospital sites. After successfully matching 2,298 (97.6%) patients, echocardiography was associated with significantly increased risks of mortality at 90 days (20.1% vs 16.8%; p = 0.004) and one year (32.9% vs 27.8%; p < 0.001), but not at 30 days (11.4% vs 9.8%; p = 0.084). Patients with echocardiography also had a mean increased delay from presentation to surgery (68.80 hours (SD 44.23) vs 39.69 hours (SD 27.09); p < 0.001), total LOS (19.49 days (SD 25.39) vs 15.94 days (SD 22.48); p < 0.001), and total healthcare costs at one year ($51,714.69 (SD 54,675.28) vs $41,861.47 (SD 50,854.12); p < 0.001).

CONCLUSION

Preoperative echocardiography for hip fracture patients is associated with increased postoperative mortality at 90 days and one year but not at 30 days. Preoperative echocardiography is also associated with increased surgical delay, postoperative LOS, and total healthcare costs at one year. Echocardiography should be considered an urgent test when ordered to prevent additional surgical delay. Cite this article: Bone Joint J 2021;103-B(2):271-278.

Fracture Risk in Patients with Myasthenia Gravis: A Population-Based Cohort Study

BACKGROUND

Prednisone is a common treatment for myasthenia gravis (MG), and osteoporosis is a known potential risk of chronic prednisone therapy.

OBJECTIVE

Our aim was to evaluate the risk of serious fractures in a population-based cohort of MG patients.

METHODS

An inception cohort of patients with MG was identified from administrative health data in Ontario, Canada between April 1, 2002 and December 31, 2015. For each MG patient, we matched 4 general population comparators based on age, sex, and region of residence. Fractures were identified through emergency department and hospitalization data. Crude overall rates and sex-specific rates of fractures were calculated for the MG and comparator groups, as well as rates of specific fractures. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression.

RESULTS

Among 3,823 incident MG patients (followed for a mean of 5 years), 188 (4.9%) experienced a fracture compared with 741 (4.8%) fractures amongst 15,292 matched comparators. Crude fracture rates were not different between the MG cohort and matched comparators (8.71 vs. 7.98 per 1000 patient years), overall and in men and women separately. After controlling for multiple covariates, MG patients had a significantly lower risk of fracture than comparators (HR 0.74, 95% CI 0.63-0.88).

CONCLUSIONS

In this large, population-based cohort of incident MG patients, MG patients were at lower risk of a major fracture than comparators. The reasons for this finding are unclear but may highlight the importance osteoporosis prevention.

The Association Between Surgeon Age and Early Surgical Complications of Elective Total Hip Arthroplasty: Propensity-Matched Cohort Study (122,043 Patients)

BACKGROUND

The aim of this study was to examine the relationship between surgeon age and early surgical complications following primary total hip arthroplasty (THA), within a year, in Ontario, Canada.

METHODS

In a propensity-matched cohort, we defined consecutive adults who received their first primary THA for osteoarthritis (2002-2018). We obtained hospital discharge abstracts, patient's demographics and physician claims. Age of the primary surgeon was determined for each procedure and used as a continuous variable for spline analysis, and as a categorical variable for subsequent matching (young <45; middle-age 45-55; older >55). The primary outcome was early surgical complications (revision, dislocation, infection). Secondary analyses included high-volume vs low-volume surgeons (≤35 THA per year).

RESULTS

We identified 122,043 THA recipients, 298 surgeons with median age 49 years. Younger, middle-aged, and older surgeons performed 39%, 29%, and 32% THAs, respectively. Middle-aged surgeons had the lowest rate of complications. Younger surgeons had a higher risk of composite complications (odds ratio [OR] 1.25, 95% confidence interval [CI] 1.09-1.44, P = .002), revision (OR 1.28, 95% CI 1.07-1.54, P = .007), and infection (OR 1.39, 95% CI 1.12-1.71, P = .003). Older surgeons also had higher risk for composite complications (OR 1.18, 95% CI 1.03-1.36, P = .019), revision (OR 1.33, 95% CI 1.10-1.62, P = .004), and dislocation (OR 1.37, 95% CI 1.08-1.73, P = .009). However, when excluding low-volume surgeons, older high-volume surgeons had similar complications to middle-aged surgeons.

CONCLUSION

Younger surgeons (<45 years) had the highest recorded complications rate while the lowest rate was for surgeons aged 45-55. Volume rather than age was more important in determining rate of complications of older surgeons.

LEVEL OF EVIDENCE

IV.