Canadian Medical Association Journal

SARS-CoV-2 strained Ontarios health system, with social determinants of health (SDH) underexplored in cost analyses. We examined COVID-19 attributable healthcare resource use and costs from the Ontario health system perspective using health administrative data. We conducted a cohort study, matching 162,633 SARS-CoV-2-exposed individuals 1:1 to unexposed individuals. We calculated 10-day per-person mean attributable costs (2023 CAD) across care phases (pre-diagnosis, acute, post-acute, terminal),...

BackgroundWe compared the risk of, testing for, and death following COVID-19 infection across three settings (long-term care homes (LTCH), shelters, the rest of the population) in the Greater Toronto Area (GTA), Canada. MethodsWe sourced person-level data from COVID-19 surveillance and reporting systems in Ontario, and examined settings with population-specific denominators (LTCH residents, shelters, and the rest of the population). We calculated cumulatively, the diagnosed cases per capita, pr...

In this population-wide study in Ontario, Canada we report on all 194,372 unique residents who received testing for SARS-CoV-2 between January 23, 2020 and April 28, 2020. We found that while more women than men were tested for SARS-CoV-2, men had a higher rate of laboratory-confirmed COVID-19 infection, hospitalization, ICU admission and death. These findings were consistent even with age adjustment, suggesting that the observed differences in outcomes between women and men were not explained b...

Introduction - Worldwide, nursing home residents have experienced disproportionately high COVID-19 mortality due to the intersection of congregate living, multimorbidity, and advanced age. Among 12 OECD countries, Canada has had the highest proportion of COVID-19 deaths in nursing home residents (78%), raising concerns about a skewed pandemic response that averted much transmission and mortality in community-dwelling residents, but did not adequately protect those in nursing homes. To investigat...

BackgroundThe impact of coronavirus disease 2019 (COVID-19) on mortality in Ontario is unknown. Cremations are performed for most deaths in Ontario and require coroner certification before the cremation can take place. Our objective was to provide timely analysis of deaths during the COVID-19 pandemic using cremation data. MethodsWe analyze cremation certificate data from January 1, 2017, to June 30, 2020, in Ontario. 2020 cremation records were compared to historical records from 2017-2019 by ...

BackgroundEpidemic waves of COVID-19 strained hospital resources. We describe temporal trends in mortality risk and length of stay in intensive cares units (ICUs) among COVID-19 patients hospitalized through the first three epidemic waves in Canada. MethodsWe used population-based provincial hospitalization data from Ontario and Quebec to examine mortality risk and lengths of ICU stay. For each province, adjusted estimates were obtained using marginal standardization of logistic regression mode...

BackgroundUnderstanding resource use for COVID-19 is critical. We conducted a population-based cohort study using public health data to describe COVID-19 associated age- and sex-specific acute care use, length of stay (LOS), and mortality. MethodsWe used Ontarios Case and Contact Management (CCM) Plus database of individuals who tested positive for COVID-19 in Ontario from March 1 to September 30, 2020 to determine age- and sex-specific hospitalizations, intensive care unit (ICU) admissions, in...

BackgroundIn central Ontario, influenza, respiratory syncytial virus (RSV), and invasive pneumococcal disease (IPD) follow similar seasonal patterns, peaking in winter. We aimed to quantify the independent and joint impact of influenza A, influenza B, and RSV on IPD risk at the population level. MethodsWe used a 2:1 self-matched case-crossover study design to evaluate acute effects of respiratory virus activity on IPD risk. This design ensures that effects are not confounded by within-individua...

BackgroundSARS-CoV-2 is currently causing a high mortality global pandemic. However, the clinical spectrum of disease caused by this virus is broad, ranging from asymptomatic infection to cytokine storm with organ failure and death. Risk stratification of individuals with COVID-19 would be desirable for management, prioritization for trial enrollment, and risk stratification. We sought to develop a prediction rule for mortality due to COVID-19 in individuals with diagnosed infection in Ontario, ...

Background: The SARS-CoV-2 disease 2019 (COVID-19) pandemic has spread across the world with varying impact on health systems and outcomes. We assessed how the type and timing of public-health interventions impacted the course of the outbreak in Alberta and the other Canadian provinces. Methods: We used publicly-available data to summarize rates of laboratory data and mortality in relation to measures implemented to contain the outbreak and testing strategy. We estimated the transmission pote...

The pandemic caused by SARS-CoV-2 has proven challenging clinically, and at the population level, due to heterogeneity in both transmissibility and severity. Recent case incidence in Ontario, Canada (autumn 2020) has outstripped incidence in seen during the first (spring) pandemic wave; but has been associated with a lower incidence of intensive care unit (ICU) admissions and deaths. We hypothesized that differential ICU burden might be explained by increased testing volumes, as well as the shif...

BackgroundThe requirement for critical care in even a modest fraction of SARS-CoV-2 infected individuals made ICU resources an important societal chokepoint during the recent pandemic. We developed a simple regression-based point score in 2020 based on an objective of forecasting critical care occupancy in the Canadian province of Ontario based on mean age of cases, case numbers, and testing volume. Evolution of the pandemic (variants of concern, vaccination) led us to re-assess and re-calibrate...

BackgroundThe COVID-19 pandemic placed immense strain on Canadas healthcare system and disproportionately affected individuals with poorer baseline health. Healthcare-associated infections (HAIs) increase risk for both patients and healthcare workers and are often more severe due to advanced age and comorbidities. While efforts have aimed to reduce in-hospital transmission, the individual- and community-level consequences of HAIs require further study. We aimed to assess whether healthcare-assoc...

BackgroundCOVID-19 has the potential to disproportionately affect the rural, remote, and Indigenous populations who typically have a worse health status and live in substandard housing, often with overcrowding. Our aim is to investigate the potential effect of COVID-19 on intensive care unit (ICU) resources and mortality in northwestern Ontario. MethodsThis study was conducted in northwestern Ontario which has a population of 230,000. A set of differential equations were used to represent a mod...

BackgroundHaving temporary immigration status affords limited rights, workplace protections, and access to services. There is not yet research data on impacts of the COVID-19 pandemic for people with temporary immigration status in Canada. MethodsWe use linked administrative data to describe SARS-CoV-2 testing, positive tests, and COVID-19 primary care service use in British Columbia from January 1, 2020, to July 31, 2021, stratified by immigration status (Citizen, Permanent Resident, Temporary...

BackgroundThe COVID-19 epidemic has taken a fearsome toll on individuals residing in long-term care facilities (LTC). As of April 10, 2020 half of Canadas COVID-19 deaths had occurred in LTC. We sought to better understand trends and risk factors for COVID-19 death in LTC in Ontario. MethodsWe analyzed a COVID-19 outbreak database created by the Ontario Ministry of Health, for the period March 29-April 7, 2020. Mortality incidence rate ratios for LTC were calculated with community living Ontari...

BackgroundAmong non-pharmaceutical interventions, individual movement restrictions have been among the most impactful methods for controlling COVID-19 case growth. While nighttime curfews to control COVID-19 case growth have been implemented in certain regions and cities, few studies have examined their impacts on mobility or COVID-19 incidence. In the second wave of COVID-19, Canadas two largest and adjacent provinces implemented lockdown restrictions with (Quebec) and without (Ontario) a night...

BackgroundThe prevalence of SARS-CoV-2 infections in Ontario is disproportionately concentrated in areas with lower-income and racialized groups. We examined whether school-level and area-level socio-economic factors were associated with elementary school student infections in Ontario. MethodsWe performed multi-level modeling analyses using data from the Ministry of Education on school-based infections in Ontario in the 2020-21 school year and on school-level demographics, the Ontario Marginali...

BackgroundThe burden of COVID-19 in Canada is unequally distributed geographically, with the largest number of cases and fatalities recorded in Quebec and Ontario while other provinces experienced limited outbreaks. To date, however, no study has assessed how provincial epidemics have unfolded in a comparative perspective. This is essential to calibrate projections of the future course of the epidemic and plan health care resources for the second wave of infections. MethodsUsing newly released ...

The rapid spread of SARS-CoV-2 in early 2020 forced provincial health authorities across Canada to quickly institute infection control measures. It is now four years since the start of the global pandemic, and an opportune time to consider how Canadas provinces compared in their SARS-CoV-2 containment policies and the resulting impacts on mortality and economic activity. I compare provincial exposure to SARS-CoV-2 using data on the number out-of-province arrivals into each province. I compare th...