Risk of Cesarean Delivery Among People With Inflammatory Bowel Disease According to Disease Characteristics: A Population-Based Study.

OBJECTIVES: It is unclear if use of cesarean delivery in people with inflammatory bowel disease (IBD) is guideline-concordant. We compared the odds of cesarean delivery among primiparous individuals with IBD versus without, overall, and by disease characteristics, as well as time to subsequent delivery. METHODS: Retrospective matched population-based cohort study between 1 April 1994 and 31 March 2020. Primiparous individuals aged 15-55 years with IBD were matched to those without IBD on age, year, hospital, and number of newborns delivered. Primary outcome was cesarean delivery versus vaginal delivery. Multivariable conditional logistic regression analyses were performed to estimate the odds of cesarean delivery among individuals with and without IBD as a binary exposure, and a categorical exposure based on IBD-related indications for cesarean delivery. Time to subsequent delivery was evaluated using a Cox proportional hazard model. RESULTS: We matched 7472 individuals with IBD to 37 360 individuals without (99.02% match rate). Individuals with IBD were categorised as having perianal (PA) disease (IBD-PA, n = 764, 10.2%), prior ileal pouch-anal anastomosis (n = 212, 2.8%), or IBD-Other (n = 6496, 86.9%). Cesarean delivery rates were 35.4% in the IBD group versus 30.4% in their controls (adjusted odds ratio 1.27; 95% CI 1.20-1.34). IBD-ileal pouch-anal anastomosis had a cesarean delivery rate of 66.5%, compared to 49.9% in IBD-PA and 32.7% in IBD-Other. There was no significant difference in the rate of subsequent delivery in those with and without IBD (adjusted hazard ratio 1.03; 95% CI 1-1.07). CONCLUSIONS: The higher risk of cesarean delivery in people with IBD reflects guideline-concordant use. Individuals with and without IBD were equally likely to have a subsequent delivery with similar timing.

A Population-Based Test-Negative Matched Case-Control Analysis of SARS-CoV-2 Vaccine Effectiveness Among Pregnant People in Ontario, Canada.

OBJECTIVE: Pregnancy is a risk factor for severe SARS-CoV-2 infection, which can result in adverse pregnancy outcomes, thus making understanding vaccine effectiveness (VE) in this population important. This study aimed to assess the VE of mRNA COVID-19 vaccines against symptomatic SARS-CoV-2 infection and COVID-19-related hospitalization in pregnant people. METHODS: Population-based matched test-negative case-control study of pregnant people aged 18-49 years, of 12 or more weeks gestation in Ontario, Canada, symptomatic with possible SARS-CoV-2 infection, and having at least 1 positive (n = 1842) or negative (n = 8524) real-time polymerase chain reaction (RT-PCR) SARS-CoV-2 test between December 14, 2020, and December 31, 2021. The exposure was receipt of ≥1 dose of mRNA COVID-19 vaccine versus no vaccination. Exposure was further stratified by number and recency of doses. The primary outcome was a positive SARS-CoV-2 RT-PCR test. As a secondary outcome, VE for COVID-19-related hospitalization was assessed. RESULTS: In the primary outcome analysis, there were 1821 positive cases, matched to 1821 negative controls. The mean (SD) maternal age was 31 (5) years. When compared to those unvaccinated, receipt of ≥1 dose was associated with an estimated VE of 39% (95% CI 29%-48%) for symptomatic infection, and 85% (95% CI 72%-92%) for COVID-19 hospitalization. VE estimates demonstrated waning with increased time since last vaccination. CONCLUSIONS: mRNA COVID-19 vaccines provide protection against symptomatic COVID-19 illness and are highly effective at preventing severe illness in pregnant people. The observed effect of vaccine waning highlights the importance of booster doses to provide optimal protection for pregnant people.

Association of Neighborhood Deprivation With Thrombolysis and Thrombectomy for Acute Stroke in a Health System With Universal Access.

BACKGROUND AND OBJECTIVES: The association between socioeconomic status and acute ischemic stroke treatments remain uncertain, particularly in countries with universal health care systems. This study aimed to investigate the association between neighborhood-level material deprivation and the odds of receiving IV thrombolysis or thrombectomy for acute ischemic stroke within a single-payer, government-funded health care system. METHODS: We conducted a population-based cohort study using linked administrative data from Ontario, Canada. This study involved all community-dwelling adult Ontario residents hospitalized with acute ischemic stroke between 2017 and 2022. Neighborhood-level material deprivation, measured in quintiles from least to most deprived, was our main exposure. We considered the receipt of thrombolysis or thrombectomy as the primary outcome. We used multivariable logistic regression models adjusted for baseline differences to estimate the association between material deprivation and outcomes. We performed a sensitivity analysis by additionally adjusting for hospital type at initial assessment. Furthermore, we tested whether hospital type modified the associations between deprivation and outcomes. RESULTS: Among 57,704 patients, those in the most materially deprived group (quintile 5) were less likely to be treated with thrombolysis or thrombectomy compared with those in the least deprived group (quintile 1) (16.6% vs 19.6%, adjusted odds ratio [aOR] 0.76, 95% CI 0.63-0.93). The association was consistent when evaluating thrombolysis (13.0% vs 15.3%, aOR 0.78, 95% CI 0.64-0.96) and thrombectomy (6.4 vs 7.8%, aOR 0.73, 95% CI 0.59-0.90) separately. There were no statistically significant differences between the middle 3 quintiles and the least deprived group. These associations persisted after additional adjustment for hospital type, and there was no interaction between material deprivation and hospital type (p interaction >0.1). DISCUSSION: We observed disparities in the use of thrombolysis or thrombectomy for acute ischemic stroke by socioeconomic status despite access to universal health care. Targeted health care policies, public health messaging, and resource allocation are needed to ensure equitable access to acute stroke treatments for all patients.

Long-term Clinical Outcomes Following Cardiac Stress Testing After Percutaneous Coronary Intervention.

BACKGROUND: Cardiac stress testing (CST) is commonly performed after percutaneous coronary intervention (PCI), yet little is known whether such ischemic testing is associated with improved clinical outcomes. METHODS: We studied patients who underwent their first PCI procedure from October 2008 to December 2016 in Ontario, Canada. Patients who underwent CST from 60 days to 1 year after PCI were compared with those who did not undergo CST. The primary outcome was a composite of cardiovascular death or hospitalisation for myocardial infarction (MI) at 3 years after CST. Inverse probability of treatment weighting was used to adjust for potential differences between the study groups. RESULTS: Among the 86,150 included patients, 40,988 (47.6%) underwent CST within 60 days to 1 year after PCI. Patients who underwent CST had higher prescription rates of cardiac medications. At 1 year after CST, rates of cardiac catheterisation and coronary revascularisation were more than double those observed in the nontested group (13.4% vs 5.9%, standardised difference [SD] 0.26, for cardiac catheterisation; 6.6% vs 2.7%, SD 0.19, for PCI). The CST group had a significantly lower primary event rate at 3 years compared without CST (3.9% vs 4.5%, hazard ratio 0.87, 95% confidence interval 0.81-0.93). CONCLUSIONS: This population-based study of PCI patients found a small but significantly lower risk of cardiovascular events among patients who received CST. Further studies are needed to confirm these findings and determine the specific aspects of care that may be associated with the modestly improved outcomes.

Sex Differences in Intensity of Care and Outcomes After Acute Ischemic Stroke Across the Age Continuum.

BACKGROUND AND OBJECTIVES: Sex differences in stroke care and outcomes have been previously reported, but it is not known whether these associations vary across the age continuum. We evaluated whether the magnitude of female-male differences in care and outcomes varied with age. METHODS: In a population-based cohort study, we identified patients hospitalized with ischemic stroke between 2012 and 2019 and followed through 2020 in Ontario, Canada, using administrative data. We evaluated sex differences in receiving intensive care unit services, mechanical ventilation, gastrostomy tube insertion, comprehensive stroke center care, stroke unit care, thrombolysis, and endovascular thrombectomy using logistic regression and reported odds ratios (ORs) and 95% CIs. We used Cox proportional hazard models and reported the hazard ratios (HRs) and 95% CI of death within 90 or 365 days. Models were adjusted for covariates and included an interaction between age and sex. We used restricted cubic splines to model the relationship between age and care and outcomes. Where the p-value for interaction was statistically significant (p < 0.05), we reported age-specific OR or HR. RESULTS: Among 67,442 patients with ischemic stroke, 45.9% were female and the median age was 74 years (64-83). Care was similar between both sexes, except female patients had higher odds of receiving endovascular thrombectomy (OR 1.35, 95% CI [1.19-1.54] comparing female with male), and these associations were not modified by age. There was no overall sex difference in hazard of death (HR 95% CI 0.99 [0.95-1.04] for death within 90 days; 0.99 [0.96-1.03] for death within 365 days), but these associations were modified by age with the hazard of death being higher in female than male patients between the ages of 50-70 years (most extreme difference around age 57, HR 95% CI 1.25 [1.10-1.40] at 90 days, p-interaction 0.002; 1.15 [1.10-1.20] at 365 days, p-interaction 0.002). DISCUSSION: The hazard of death after stroke was higher in female than male patients aged 50-70 years. Examining overall sex differences in outcomes without accounting for the effect modification by age may miss important findings in specific age groups.

Association of Race and Ethnicity With Obstructive Coronary Artery Disease.

Background: Appropriate selection of patients with stable coronary artery disease (CAD) for coronary angiography is dependent on the pretest probability of obstructive CAD; however, little is known about the potential differences in CAD by race and ethnic groups. Objectives: The purpose of this study was to evaluate the association of race and ethnicity with coronary obstruction in stable CAD. Methods: We evaluated first coronary angiography for CAD evaluation between 2012 and 2019 in Ontario, Canada. Race and ethnicity were identified by physicians. The main outcome was the rate of obstructive CAD (left main stenosis ≥50% or major epicardial vessel stenosis ≥70%). Multivariable logistic regression analyses evaluated the independent association of race and ethnicity with CAD. Results: Among 71,199 CAD patients, 14.0% were South Asian (SA), 4.4% were East Asian (EA), and 58,131 were White patients. SA patients were the youngest at 60.9 years vs 62.4 years for EA patients and 65.1 years for White patients but were most likely to have obstructive CAD (46.9%) (EA 43.0% and White patients 37.9%). SA patients had the highest prevalence of 3-vessel CAD at 13.4% (vs 12.5% in EA and 7.7% in White patients). The adjusted odds ratio was 67% higher (1.67; 95% CI: 1.59 to 1.75) for having obstructive CAD in SA patients than that in White patients. EA patients also had significantly increased adjusted odds of obstructive CAD compared with White patients (1.40; 95% CI: 1.29-1.52). Conclusions: SA patients were younger at presentation but had the highest adjusted odds of obstructive CAD. Incorporation of race and ethnicity information may improve risk-prediction tools for detection of coronary obstruction.

Eligibility and Implementation of Rivaroxaban for Secondary Prevention of Atherothrombosis in Clinical Practice-Insights From the CANHEART Study.

Background The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial decreased major adverse cardiovascular events with very low-dose rivaroxaban and aspirin in patients with coronary artery disease and peripheral artery disease. We examined the eligibility and potential real-world impact of this strategy on the COMPASS-eligible population. Methods and Results COMPASS eligibility criteria were applied to the CANHEART (Cardiovascular Health in Ambulatory Care Research Team) registry, a population-based cohort of Ontario adults. We compared 5-year major adverse cardiovascular events and major bleeding rates stratified by COMPASS eligibility and by clinical risk factors. We applied COMPASS trial rivaroxaban/aspirin arm hazard ratios to estimate the potential impact on the COMPASS-eligible cohort. Among 362 797 patients with coronary artery disease or peripheral artery disease, 38% were deemed eligible, 47% ineligible, and 15% indeterminate. Among eligible patients, a greater number of risk factors was associated with higher rates of cardiovascular outcomes, whereas bleeding rates increased minimally. Over 5 years, applying COMPASS treatment effects to eligible patients resulted in a 2.4% absolute risk reduction of major adverse cardiovascular events and a number needed to treat of 42, and a 1.3% absolute risk increase of major bleeding and number needed to harm (NNH) of 77. Those with at least 2 risk factors had a 3.0% absolute risk reduction of major adverse cardiovascular events (number needed to treat =34) and a 1.6% absolute risk increase of major bleeding (number needed to harm =61). Conclusions Implementation of very-low-dose rivaroxaban therapy would potentially impact ≈$$ \approx $$2 in 5 patients with atherosclerotic disease in Ontario. Eligible individuals with ≥$$ \ge $$2 comorbidities represent a high-risk subgroup that may derive the greatest benefit-to-risk ratio. Selection of patients with high-risk predisposing factors appears appropriate in routine practice.

Telemedicine use and outcomes after transient ischemic attack and minor stroke during the COVID-19 pandemic: a population-based cohort study.

BACKGROUND: The COVID-19 pandemic has led to an increase in telemedicine use. We compared care and outcomes in patients with transient ischemic attack (TIA) or minor ischemic stroke before and after the widespread adoption of telemedicine in Ontario, Canada, in 2020. METHODS: In a population-based cohort study using linked administrative data, we identified patients with TIA or ischemic stroke discharged from any emergency department in Ontario before the widespread use of telemedicine (Apr. 1, 2015, to Mar. 31, 2020) and after (Apr. 1, 2020, to Mar. 31, 2021). We measured care, including visits with a physician, investigations and medication renewal. We compared 90-day death before and after 2020 using Cox proportional hazards models, and we compared 90-day admission using cause-specific hazard models. RESULTS: We identified 47 601 patients (49.3% female; median age 73, interquartile range 62-82, yr) with TIA (n = 35 695, 75.0%) or ischemic stroke (n = 11 906, 25.0%). After 2020, 83.1% of patients had 1 or more telemedicine visit within 90 days of emergency department discharge, compared with 3.8% before. The overall access to outpatient visits within 90 days remained unchanged (92.9% before v. 94.0% after; risk difference 1.1, 95% confidence interval [CI] -1.3 to 3.5). Investigations and medication renewals were unchanged. Clinical outcomes were also similar before and after 2020; the adjusted hazard ratio was 0.97 (95% CI 0.91 to 1.04) for 90-day all-cause admission, 1.06 (95% CI 0.94 to 1.20) for stroke admission and 1.07 (95% CI 0.93 to 1.24) for death. INTERPRETATION: Care and short-term outcomes after TIA or minor stroke remained stable after the widespread implementation of telemedicine during the COVID-19 pandemic. Our findings suggest that telemedicine is an effective method of health care delivery that can be complementary to in-person care for minor ischemic cerebrovascular events.

Comparison of machine learning and the regression-based EHMRG model for predicting early mortality in acute heart failure.

BACKGROUND: Although risk stratification of patients with acute decompensated heart failure (HF) is important, it is unknown whether machine learning (ML) or conventional statistical models are optimal. We developed ML algorithms to predict 7-day and 30-day mortality in patients with acute HF and compared these with an existing logistic regression model at the same timepoints. METHODS: Patients presenting to one of 86 hospitals, who were either admitted to hospital or discharged home directly from the emergency department, were randomly selected using stratified random sampling. ML approaches, including neural networks, random forest, XGBoost, and the Lasso, were compared with a validated logistic regression model for discrimination and calibration. RESULTS: Among 12,608 patients in our analysis, lasso regression (c-statistic 0.774; 95% CI, 0.743, 0.806) performed better than other ML models for 7-day mortality but did not outperform the baseline logistic regression model (0.794; 95% CI, 0.789, 0.800). For 30-day mortality, XGBoost performed better than other ML models (c-statistic 0.759; 95% CI; 0.740, 0.779), but was not significantly better than logistic regression (c-statistic 0.755; 95% CI, 0.750, 0.762). Logistic regression demonstrated better calibration at 7 days (calibration-in-the-large 0.017; 95% CI, -0.657, 0.692, and calibration slope 0.954; 95% CI, 0.769, 1.139), and at 30 days (-0.026; 95% CI, -0.374, 0.322, and 0.964; 95% CI, 0.831, 1.098), and best Brier scores, compared to ML approaches. CONCLUSIONS: Logistic regression was comparable to ML in discrimination, but was superior to ML algorithms in calibration overall. ML algorithms for prognosis should routinely report calibration metrics in addition to discrimination.

Emergency Department Visits, Care, and Outcome After Stroke and Myocardial Infarction During the COVID-19 Pandemic Phases.

BACKGROUND: It is not known if initial reductions in hospitalization for stroke and myocardial infarction early during the coronavirus disease-2019 pandemic were followed by subsequent increases. We describe the rates of emergency department visits for stroke and myocardial infarction through the pandemic phases. METHODS: We used linked administrative data to compare the weekly age- and sex-standardized rates of visits for stroke and myocardial infarction in Ontario, Canada in the first 9 months of 2020 to the mean baseline rates (2015-2019) using rate ratios (RRs) and 95% confidence intervals (CIs). We compared care and outcomes by pandemic phases (pre-pandemic was January-March, lockdown was March-May, early reopening was May-July, and late reopening was July-September). RESULTS: We identified 15,682 visits in 2020 for ischemic stroke (59.2%; n = 9279), intracerebral hemorrhage (12.2%; n = 1912), or myocardial infarction (28.6%; n = 4491). The weekly rates for stroke visits in 2020 were lower during the lockdown and early reopening than at baseline (RR 0.76, 95% CI [0.66, 0.87] for the largest weekly decrease). The weekly rates for myocardial infarction visits were lower during the lockdown only (RR 0.61, 95% CI [0.46, 0.77] for the largest weekly decrease), and there was a compensatory increase in visits following reopening. Ischemic stroke 30-day mortality was increased during the lockdown phase (11.5% pre-coronavirus disease; 12.2% during lockdown; 9.2% during early reopening; and 10.6% during late reopening, P = 0.015). CONCLUSION: After an initial reduction in visits for stroke and myocardial infarction, there was a compensatory increase in visits for myocardial infarction. The death rate after ischemic stroke was higher during the lockdown than in other phases.

CONTEXTE: Nous ignorons si les réductions des taux d'hospitalisations pour un AVC et un infarctus du myocarde observées au début de la pandémie de coronavirus de 2019 ont été suivies d'une hausse de ces taux. Nous décrivons ici les taux de visites aux services des urgences pour un AVC et un infarctus du myocarde pendant toutes les phases de la pandémie. MÉTHODES: À partir de données administratives couplées, nous comparons les taux hebdomadaires de visites pour un AVC et un infarctus du myocarde, normalisés en fonction de l'âge et du sexe, en Ontario, au Canada, effectuées pendant les neuf premiers mois de 2020, avec les taux moyens de base (2015-2019), en utilisant des ratios des taux (RR) et des intervalles de confiance (IC) à 95 %. Nous avons comparé les soins et les issues selon les phases de la pandémie (avant la pandémie : de janvier à mars; confinement : de mars à mai; début de la réouverture : de mai à juillet; phase tardive de la réouverture : de juillet à septembre). RÉSULTATS: Nous avons répertorié 15 682 visites effectuées en 2020 pour un AVC ischémique (59,2 %; n = 9 279), une hémorragie intracérébrale (12,2 %; n = 1 912) ou un infarctus du myocarde (28,6 %; n = 4 491). Les taux hebdomadaires de visites pour un AVC effectuées en 2020 étaient inférieurs pendant la période de confinement et le début de la réouverture comparativement à la période de base (RR : 0,76; IC à 95 % : 0,66-0,87 pour la plus grande baisse hebdomadaire). Les taux hebdomadaires de visites pour un infarctus du myocarde étaient inférieurs pendant la période de confinement seulement (RR : 0,61; IC à 95 % : 0,46-0,77 pour la baisse hebdomadaire la plus importante); une hausse compensatrice du nombre de visites a été notée après la réouverture. Le taux de mortalité à 30 jours des suites d'un AVC ischémique était plus élevé pendant la période de confinement (11,5 % avant la pandémie de coronavirus; 12,2 % pendant le confinement; 9,2 % au début de la période de réouverture; 10,6 % pendant la phase tardive de la réouverture, p = 0,015). CONCLUSION: Après une réduction initiale du nombre de visites motivées par un AVC et un infarctus du myocarde, on a noté une hausse compensatrice du nombre de visites motivées par un infarctus du myocarde. Le taux de mortalité des suites d'un AVC ischémique était plus élevé pendant la période de confinement que pendant les autres périodes.

Association of Neighborhood-Level Material Deprivation With Health Care Costs and Outcome After Stroke.

OBJECTIVE: To determine the association between material deprivation and direct healthcare costs and clinical outcomes following stroke in the context of a publicly funded universal healthcare system. METHODS: In this population-based cohort study of patients with ischemic and hemorrhagic stroke admitted to hospital between 2008 and 2017 in Ontario, Canada, we used linked administrative data to identify the cohort, predictor variables, and outcomes. The exposure was a five-level neighborhood material deprivation index. The primary outcome was direct healthcare costs incurred by the public payer in the first year. Secondary outcomes were death and admission to long-term care. RESULTS: Among 90,289 patients with stroke, the mean (standard deviation) per-person costs increased with increasing material deprivation, from $50,602 ($55,582) in the least deprived quintile to $56,292 ($59,721) in the most deprived quintile (unadjusted relative cost ratio and 95% confidence intervals 1.11 [1.08,1.13] and adjusted relative cost ratio 1.07 [1.05,1.10] for least compared to most deprived quintile). People in the most deprived quintile had higher mortality within one year compared to the least deprived quintile (adjusted hazard ratio (HR) 1.07 [1.03,1.12]) as well as within three years (adjusted HR 1.09 [1.05,1.13]). Admission to long-term care increased incrementally with material deprivation and those in the most deprived quintile had an adjusted HR of 1.33 [1.24,1.43]) compared to those in the least deprived quintile. CONCLUSION: Material deprivation is a risk factor for increased costs and poor outcomes after stroke. Interventions targeting health inequities due to social determinants of health are needed. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that the neighborhood-level material deprivation predicts direct healthcare costs.

Factors Associated With Nonreceipt of Recommended COPD Medications: A Population Study.

BACKGROUND: COPD medications reduce exacerbations and improve quality of life. Despite this, some individuals do not receive medications recommended by practice guidelines. RESEARCH QUESTION: How common is nonreceipt of recommended medications among people with COPD, and what factors are associated with nonreceipt? STUDY DESIGN AND METHODS: This population cohort study was conducted in Ontario, Canada, a province with universal health care insurance and medication coverage for those aged ≥ 65 years. Health administrative data were used to identify people aged ≥ 66 years with physician-diagnosed COPD as of 2018 and group them into cohorts of lower or higher risk for future COPD exacerbations. Proportions of patients in each group who did not receive medications recommended by COPD guidelines were determined. Generalized estimating equation modeling was used to determine associations between patient and physician factors and nonreceipt of recommended medications. RESULTS: About 54% and 88% of people with COPD received sufficient recommended medications in the low and high risk of exacerbation groups, respectively. Longer duration of COPD, higher comorbidity, dementia, and older physician age were associated with nonreceipt of recommended medications in both groups. People who had a co-diagnosis of asthma, who received care by a pulmonologist and who received spirometry were more likely to receive recommended medication. INTERPRETATION: COPD medications seem underused by the COPD population, and various factors are associated with suboptimal receipt. Targeting these factors would help improve the care and health of people with COPD.

Stroke care and case fatality in people with and without schizophrenia: a retrospective cohort study.

BACKGROUND: Schizophrenia is associated with an increased risk of death following stroke; however, the magnitude and underlying reasons for this are not well understood. OBJECTIVE: To determine the association between schizophrenia and stroke case fatality, adjusting for baseline characteristics, stroke severity and processes of care. DESIGN: Retrospective cohort study used linked clinical and administrative databases. SETTING: All acute care institutions (N=152) in the province of Ontario, Canada. PARTICIPANTS: All patients (N=52 473) hospitalised with stroke between 1 April 2002 and 31 March 2013 and included in the Ontario Stroke Registry. Those with schizophrenia (n=612) were identified using validated algorithms. MAIN OUTCOMES AND MEASURES: We compared acute stroke care in those with and without schizophrenia and used Cox proportional hazards models to examine the association between schizophrenia and mortality, adjusting for demographics, comorbidity, stroke severity and processes of care. RESULTS: Compared with those without schizophrenia, people with schizophrenia were less likely to undergo thrombolysis (10.1% vs 13.4%), carotid imaging (66.3% vs 74.0%), rehabilitation (36.6% vs 46.6% among those with disability at discharge) or be treated with antihypertensive, lipid-lowering or anticoagulant therapies. After adjustment for age and other factors, schizophrenia was associated with death from any cause at 1 year (adjusted HR (aHR) 1.33, 95% CI 1.14 to 1.54). This was mainly attributable to early deaths from stroke (aHR 1.47, 95% CI 1.20 to 1.80, with survival curves separating in the first 30 days), and the survival disadvantage was particularly marked in those aged over 70 years (1-year mortality 46.9% vs 35.0%). CONCLUSIONS: Schizophrenia is associated with increased stroke case fatality, which is not fully explained by stroke severity, measurable comorbid conditions or processes of care. Future work should focus on understanding this mortality gap and on improving acute stroke and secondary preventive care in people with schizophrenia.

Sex differences in direct healthcare costs following stroke: a population-based cohort study.

BACKGROUND: The economic burden of stroke on the healthcare system has been previously described, but sex differences in healthcare costs have not been well characterized. We described the direct person-level healthcare cost in men and women as well as the various health settings in which costs were incurred following stroke. METHODS: In this population-based cohort study of patients admitted to hospital with stroke between 2008 and 2017 in Ontario, Canada, we used linked administrative data to calculate direct person-level costs in Canadian dollars in the one-year following stroke. We used a generalized linear model with a gamma distribution and a log link function to compare costs in women and men with and without adjustment for baseline clinical differences. We also assessed for an interaction between age and sex using restricted cubic splines to model the association of age with costs. RESULTS: We identified 101,252 patients (49% were women, median age [Q1-Q3] was 76 years [65-84]). Unadjusted costs following stroke were higher in women compared to men (mean ± standard deviation cost was $54,012 ± 54,766 for women versus $52,829 ± 59,955 for men, and median cost was $36,703 [$16,496-$72,227] for women versus $32,903 [$15,485-$66,007] for men). However, after adjustment, women had 3% lower costs compared to men (relative cost ratio and 95% confidence interval 0.97 [0.96,0.98]). The lower cost in women compared to men was most prominent among people aged over 85 years (p for interaction = 0.03). Women incurred lower costs than men in outpatient care and rehabilitation, but higher costs in complex continuing care, long-term care, and home care. CONCLUSIONS: Patterns of resource utilization and direct medical costs were different between men and women after stroke. Our findings inform public payers of the drivers of costs following stroke and suggest the need for sex-based cost-effectiveness evaluation of stroke interventions with consideration of costs in all care settings.

Use of administrative record linkage to measure medical and social risk factors for early developmental vulnerability in Ontario, Canada.

BACKGROUND: Linkage of demographic, health, and developmental administrative data can enrich population-based surveillance and research on developmental and educational outcomes. Transparency of the record linkage process and results are required to assess potential biases. OBJECTIVES: To describe the approach used to link records of kindergarten children from the Early Development Instrument (EDI) in Ontario to health administrative data and test differences in characteristics of children by linkage status. We demonstrate how socio-demographic and medical risk factors amass in their contribution to early developmental vulnerability and test the concordance of health diagnoses in both the EDI and health datasets of linked records. METHODS: Children with records in the 2015 EDI cycle were deterministically linked to a population registry in Ontario, Canada. We compared sociodemographic and developmental vulnerability data between linked and unlinked records. Among linked records, we examined the contribution of medical and social risk factors obtained from health administrative data to developmental vulnerability identified in the EDI using descriptive analyses. RESULTS: Of 135,937 EDI records, 106,217 (78.1%) linked deterministically to a child in the Ontario health registry using birth date, sex, and postal code. The linked cohort was representative of children who completed the EDI in age, sex, rural residence, immigrant status, language, and special needs status. Linked data underestimated children living in the lowest neighbourhood income quintile (standardized difference [SD] 0.10) and with higher vulnerability in physical health and well-being (SD 0.11) , social competence (SD 0.10), and language and cognitive development (SD 0.12). Analysis of linked records showed developmental vulnerability is sometimes greater in children with social risk factors compared to those with medical risk factors. Common childhood conditions with records in health data were infrequently recorded in EDI records. CONCLUSIONS: Linkage of early developmental and health administrative data, in the absence of a single unique identifier, can be successful with few systematic biases introduced. Cross-sectoral linkages can highlight the relative contribution of medical and social risk factors to developmental vulnerability and poor school achievement.

Hospital admission for stroke or transient ischemic attack among First Nations people with diabetes in Ontario: a population-based cohort study.

BACKGROUND: First Nations people have high rates of diabetes mellitus, which is a risk factor for stroke. We studied the rates of hospital admission, processes of care and outcomes of stroke and transient ischemic attack (TIA) in First Nations people in Ontario. METHODS: Using linked administrative databases, we identified annual cohorts of people aged 20-105 years in Ontario with prevalent diabetes between Apr. 1, 1995, and Mar. 31, 2015. We identified Status First Nations people in Ontario from the Indian Register. We compared age- and sex-standardized rates of hospital admission for stroke or TIA, processes of care and case fatality among First Nations versus other people in Ontario with diabetes. RESULTS: Overall, 28 874 people with diabetes (of whom 536 were First Nations people) were admitted to hospital with a stroke or TIA between Apr. 1, 2011, and Mar. 31, 2016. Admission rates for stroke or TIA declined over the study period but were higher among First Nations people than other Ontarians in most years after 2005/06. First Nations people admitted with stroke or TIA were as likely as other Ontarians to undergo neuroimaging within 24 hours (94.6% v. 96.0%), be discharged to inpatient rehabilitation (31.8% v. 34.8%) and receive carotid revascularization (1.4% v. 2.7%), but were less likely to receive thrombolysis (6.3% v. 11.0%). Age- and sex-standardized stroke case fatality was similar in First Nations people and other Ontarians at 7 days (12.0% v. 8.5%), 30 days (19.2% v. 16.0%) and 1 year (33.8% v. 28.1%). INTERPRETATION: Rates of hospital admission for stroke or TIA were higher among First Nations people than other people with diabetes in Ontario. Future work should focus on determining Indigenous-specific determinants of health related to this disparity and implementing appropriate interventions to mitigate the risks and sequelae of stroke in First Nations people.

Deriving a Passive Surveillance Stroke Severity Indicator From Routinely Collected Administrative Data: The PaSSV Indicator.

BACKGROUND: Adjusting for stroke severity is crucial for stroke outcomes research. However, this information is not available in administrative healthcare data. We aimed to derive an indicator of baseline stroke severity using these data. METHODS AND RESULTS: We identified patients with stroke enrolled in a population-based registry in Ontario, Canada, and used the Canadian Neurological Scale (CNS), documented in the registry, as a measure of stroke severity. We derived an estimated CNS from a linear regression model in which we regressed the observed CNS on predictor variables: age, sex, arrival by ambulance, interhospital transfer, mechanical ventilation, and an emergency department triage score. The effect of stroke severity on the estimated hazard ratios for 30-day mortality was determined in 3 Cox-proportional hazards models with (1) no CNS, (2) observed CNS, and (3) estimated CNS, all adjusted for age, sex, Charlson index, and stroke type. We assessed model discrimination using C statistics. To assess for construct validity, we repeated these analyses in a subset of patients with documented National Institute of Health Stroke Scale and in a cohort of patients with stroke external to the registry. We derived the estimated stroke severity in 41 481 patients (48.7% female, median age of 75 years [interquartile range, 64- 83]). The magnitude of the association between stroke severity and mortality was similar for the observed and estimated CNS. The discriminative ability of the Cox-proportional hazards models to predict mortality was highest when the observed CNS was included (C statistic, 0.82 [95% CI, 0.81-0.82]), moderate with estimated CNS (0.76 [0.75-0.76]), and lowest without CNS (0.69 [0.69-0.70]. Our findings were replicated with the National Institute of Health Stroke Scale and in the external cohort. CONCLUSIONS: We derived an estimated measure of stroke severity using administrative data. This can be applied for risk adjustment in population-based stroke outcomes research and in assessments of health system performance.

Geographic Access to Stroke Care Services in Rural Communities in Ontario, Canada.

BACKGROUND: Optimal stroke care requires access to resources such as neuroimaging, acute revascularization, rehabilitation, and stroke prevention services, which may not be available in rural areas. We aimed to determine geographic access to stroke care for residents of rural communities in the province of Ontario, Canada. METHODS: We used the Ontario Road Network File database linked with the 2016 Ontario Acute Stroke Care Resource Inventory to estimate the proportion of people in rural communities, defined as those with a population size <10,000, who were within 30, 60, and 240 minutes of travel time by car from stroke care services, including brain imaging, thrombolysis treatment centers, stroke units, stroke prevention clinics, inpatient rehabilitation facilities, and endovascular treatment centers. RESULTS: Of the 1,496,262 people residing in rural communities, the majority resided within 60 minutes of driving time to a center with computed tomography (85%), thrombolysis (81%), a stroke unit (68%), a stroke prevention clinic (74%), or inpatient rehabilitation (77.0%), but a much lower proportion (32%) were within 60 minutes of driving time to a center capable of providing endovascular thrombectomy (EVT). CONCLUSIONS: Most rural Ontario residents have appropriate geographic access to stroke services, with the exception of EVT. This information may be useful for jurisdictions seeking to optimize the regional organization of stroke care services.

Influenza Vaccine Effectiveness in Preventing Hospitalizations in Older Patients With Chronic Obstructive Pulmonary Disease.

BACKGROUND: Annual influenza immunization is recommended for people with chronic obstructive pulmonary disease (COPD) by all major COPD clinical practice guidelines. We sought to determine the seasonal influenza vaccine effectiveness (VE) against laboratory-confirmed influenza-associated hospitalizations among older adults with COPD. METHODS: We conducted a test-negative study of influenza VE in community-dwelling older adults with COPD in Ontario, Canada using health administrative data and respiratory specimens collected from patients tested for influenza during the 2010-11 to 2015-16 influenza seasons. Influenza vaccination was ascertained from physician and pharmacist billing claims. Multivariable logistic regression was used to estimate the adjusted odds ratio of influenza vaccination in people with, compared to those without, laboratory-confirmed influenza. RESULTS: Receipt of seasonal influenza vaccine was associated with an adjusted 22% (95% confidence interval [CI], 15%-27%) reduction in laboratory-confirmed influenza-associated hospitalization. Adjustment for potential misclassification of vaccination status increased this to 43% (95% CI, 35%-52%). Vaccine effectiveness was not found to vary by patient- or influenza-related variables. CONCLUSIONS: During the studied influenza seasons, influenza vaccination was at least modestly effective in reducing laboratory-confirmed influenza-associated hospitalizations in people with COPD. The imperfect effectiveness emphasizes the need for better influenza vaccines and other preventive strategies.

Developing an adapted Charlson comorbidity index for ischemic stroke outcome studies.

BACKGROUND: The Charlson comorbidity index (CCI) is commonly used to adjust for patient casemix. We reevaluated the CCI in an ischemic stroke (IS) cohort to determine whether the original seventeen comorbidities and their weights are relevant. METHODS: We identified an IS cohort (N = 6988) from the Ontario Stroke Registry (OSR) who were discharged from acute hospitals (N = 100) between April 1, 2012 and March 31, 2013. We used hospital discharge ICD-10-CA data to identify Charlson comorbidities. We developed a multivariable Cox model to predict one-year mortality retaining statistically significant (P < 0.05) comorbidities with hazard ratios ≥1.2. Hazard ratios were used to generate revised weights (1-6) for the comorbid conditions. The performance of the IS adapted Charlson comorbidity index (ISCCI) mortality model was compared to the original CCI using the c-statistic and continuous Net Reclassification Index (cNRI). RESULTS: Ten of the 17 Charlson comorbid conditions were retained in the ISCCI model and 7 had reassigned weights when compared to the original CCI model . The ISCCI model showed a small but significant increase in the c-statistic compared to the CCI for 30-day mortality (c-statistic 0.746 vs. 0.732, p = 0.009), but no significant increase in c-statistic for in-hospital or one-year mortality. There was also no improvement in the cNRI when the ISCCI model was compared to the CCI. CONCLUSIONS: The ISCCI model had similar performance to the original CCI model. The key advantage of the ISCCI model is it includes seven fewer comorbidities and therefore easier to implement in situations where coded data is unavailable.