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.

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.

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.

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.