Project description:We aimed to determine whether early public health interventions in 2020 mitigated the association of sociodemographic and clinical risk factors with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We conducted a population-based cohort study of all adults in Ontario, Canada who underwent testing for SARS-CoV-2 through December 31, 2020. The outcome was laboratory-confirmed SARS-CoV-2 infection, determined by reverse transcription polymerase chain reaction testing. Adjusted odds ratios (ORs) were determined for sociodemographic and clinical risk factors before and after the first-wave peak of the pandemic to assess for changes in effect sizes. Among 3,167,753 community-dwelling individuals, 142,814 (4.5%) tested positive. The association between age and SARS-CoV-2 infection risk varied over time (P-interaction < 0.0001). Prior to the first-wave peak, SARS-CoV-2 infection increased with age whereas this association reversed thereafter. Risk factors that persisted included male sex, residing in lower income neighborhoods, residing in more racially/ethnically diverse communities, immigration to Canada, hypertension, and diabetes. While there was a reduction in infection rates after mid-April 2020, there was less impact in regions with higher racial/ethnic diversity. Immediately following the initial peak, individuals living in the most racially/ethnically diverse communities with 2, 3, or ≥ 4 risk factors had ORs of 1.89, 3.07, and 4.73-fold higher for SARS-CoV-2 infection compared to lower risk individuals in their community (all P < 0.0001). In the latter half of 2020, this disparity persisted with corresponding ORs of 1.66, 2.48, and 3.70-fold higher, respectively. In the least racially/ethnically diverse communities, there was little/no gradient in infection rates across risk strata. Further efforts are necessary to reduce the risk of SARS-CoV-2 infection among the highest risk individuals residing in the most racially/ethnically diverse communities.

Project description:BackgroundHealth care workers have a higher risk of acquiring SARS-CoV-2 infection than the general population. Our study reports on SARS-CoV-2 testing, infection and associated outcomes in Ontario physicians before SARS-CoV-2 vaccination became available on Dec. 14, 2020.MethodsWe conducted a descriptive, population-based cohort study of physicians in Ontario, Canada, from Jan. 25 to Dec. 31, 2020. We included physicians and postgraduate medical trainees who were residents of Ontario and registrants with the College of Physicians and Surgeons of Ontario during the study period. We examined the proportion of physicians tested for SARS-CoV-2 infection, the proportion who tested positive, and how testing and infections varied by certain physician characteristics. We reported on clinical outcomes associated with infection, including hospital admission and death.ResultsOf 41 208 physicians (mean age 47 yr; 56.1% male), 19 116 (46.4%) were tested at least once for SARS-CoV-2 infection; 358 tested positive (0.9%). No physicians died within 30 days of testing positive; however, 20/358 (5.6%) were admitted to hospital. By specialty, the proportion tested was highest among postgraduate medical trainees (2531/4125 [61.4%]), emergency physicians (281/478 [58.8%]), infectious disease physicians (33/67 [49.3%]) and family physicians (8857/18 553 [47.7%]). The proportion who tested positive was highest among internal medicine physicians (44/3499 [1.3%]), postgraduate medical trainees (47/4125 [1.1%]) and family physicians (171/18 553 [0.9%]). Of 2290 physicians who worked in long-term care, 1636 (71.4%) were tested and 25 (1.1%) tested positive.InterpretationDuring the prevaccination period of the COVID-19 pandemic in Ontario, nearly half of all physicians in the province were tested at least once for SARS-CoV-2 infection, 0.9% tested positive and none died. These findings may reflect the public health measures that were implemented in the province during this period.

Project description:BackgroundHesitancy about vaccination during pregnancy posed challenges to SARS-CoV-2 vaccination efforts. We aimed to examine rates of SARS-CoV-2 vaccination among Ontario residents who gave birth in early 2022, and to compare rates of SARS-CoV-2 vaccine uptake with rates of tetanus, diphtheria, and pertussis (Tdap) and influenza vaccination during pregnancy in 2019, 2021, and 2022.MethodsWe conducted a population-based retrospective cohort study to describe vaccination rates among pregnant and comparable nonpregnant populations in Ontario using linked administrative data. Provincially insured females who had a live, in-hospital birth from Jan. 1 to Mar. 31 in 2019, 2021, or 2022 were our primary cohort. Using log-binomial regression, we tested associations between SARS-CoV-2 (2022) and Tdap and influenza (2019, 2021, 2022) vaccination status, with birth group and covariates. We compared SARS-CoV-2 vaccination status with the status of a matched cohort of nonpregnant females and conducted subgroup analyses by age and prenatal clinician type.ResultsAmong birthing people, 78.7% received their first SARS-CoV-2 vaccine dose and 74.2% received a second dose. The rate was significantly higher among nonpregnant comparators (dose 1: relative risk [RR] 0.94, 95% confidence interval [CI] 0.93-0.94; dose 2: RR 0.91, 95% CI 0.90-0.91). However, the rate of SARS-CoV-2 vaccination uptake among birthing people was higher than uptake of Tdap or influenza vaccination. Tetanus, diphtheria, and pertussis vaccination increased over time from 22.2% in 2019 to 32.6% in 2022, and influenza vaccination rose to 35.3% in 2021 but returned to prepandemic levels in 2022 (27.7%). Vaccination rates were lower among pregnant people who were young, multiparous, or residents of rural or economically deprived areas for all 3 vaccines.InterpretationRates of SARS-CoV-2 vaccination were lower among pregnant people than among nonpregnant comparators but were higher than rates of routinely recommended Tdap and influenza vaccinations. Pandemic urgency may have overcome a great deal of hesitancy about vaccinating against SARS-CoV-2 during pregnancy in 2022, but uptake of routinely recommended vaccines in pregnancy remains a challenge.Trial registrationClinicaltrials.gov, no. NCT05663762.

Project description:BackgroundProstate cancer incidence has been associated with various sociodemographic factors, such as race, income and age, but the association with immigrant status in Canada is unclear. In this population-based study in Ontario, Canada, we compared age-standardized incidence rates for immigrant males from various regions of origin with the rates of long-term residents.MethodsIn this retrospective cohort study, we linked several provincial-level databases available at ICES, an independent, non-profit research institute. We included all males aged 20 years and older in the province of Ontario eligible for health care for each fiscal year (Apr. 1 to Mar. 31) in 2008-2016. We determined age-standardized prostate cancer incidence rates, stratifying by immigrant status (a binary variable) and region of origin. We used a log-binomial model to estimate adjusted incidence rate ratios, with long-term residents (Canadian-born Ontarians as well as those who immigrated before 1985, when available data on immigration starts) as the reference group. We included age, neighbourhood income and time since landing in the models. Additional models limited to immigrant males in the cohort included immigration admission category (economic class, family class, refugee, other) and time since landing in Canada.ResultsThere were 74594 incident cases of prostate cancer in the study period, 6742 of which were among immigrant males. Males who had immigrated from West Africa and the Caribbean had significantly higher incidence of prostate cancer than other immigrants and long-term residents: adjusted rate ratios of 2.71 (95% confidence interval [CI] 2.41-3.05) and 1.91 (95% CI 1.78-2.04), respectively. Immigrants from other regions, including East Africa and Middle-Southern Africa, had lower or similar incidence rates to long-term residents. Males from South Asia had the lowest adjusted rate ratio (0.47, 95% CI 0.45-0.50).InterpretationThe age-standardized incidence rate of prostate cancer from 2008 to 2016 was consistently and significantly higher among immigrants from West African and Caribbean countries than among other immigrants and long-term residents of the province. Future research in Canada should focus on further understanding heterogeneity in prostate cancer risk and epidemiology, including stage of diagnosis and mortality, for immigrants.

Project description:BackgroundLung cancer is one of the most common cancers and causes of cancer death in Canada. Some previous literature suggests that socioeconomic inequalities in lung cancer screening, treatment and survival may exist. The objective of this study was to compare overall survival for immigrants versus long-term residents of Ontario, Canada among patients diagnosed with lung cancer.MethodsThis population-based retrospective cohort study utilized linked health administrative databases and identified all individuals (immigrants and long-term residents) aged 40 + years diagnosed with incident lung cancer between April 1, 2012 and March 31, 2017. The primary outcome was 5-year overall survival with December 31, 2019 as the end of the follow-up period. We implemented adjusted Cox proportional hazards models stratified by age at diagnosis, sex, and cancer stage at diagnosis to examine survival.ResultsThirty-eight thousand seven hundred eighty-eight individuals diagnosed with lung cancer were included in our cohort including 7% who were immigrants. Immigrants were younger at diagnosis and were more likely to reside in the lowest neighbourhood income quintile (30.6% versus 24.5%) than long-term residents. After adjusting for age at diagnosis, neighbourhood income quintile, comorbidities, visits to primary care in the 6 to 30 months before diagnosis, continuity of care, cancer type and cancer stage at diagnosis, immigrant status was associated with a lower hazard of dying 5-years post-diagnosis for both females (0.7; 95% CI 0.6-0.8) and males (0.7; 95% CI 0.6-0.7) in comparison to long-term residents. This trend held in adjusted models stratified by cancer stage at diagnosis. For example, female immigrants diagnosed with early stage lung cancer had a hazard ratio of 0.5 (95% CI 0.4-0.7) in comparison to long-term residents.ConclusionOverall survival post diagnosis with lung cancer was better among Ontario immigrants versus long-term residents. Additional research, potentially on the protective effects of immigrant enclave and the intersection of immigrant status with racial/ethnic identity, is needed to further explore why better overall survival for immigrants remained.

Project description:ImportanceUnderstanding the evolving characteristics of pediatric patients hospitalized for eating disorders is important to ensure that services and treatments align with patient needs.ObjectiveTo examine temporal trends in the rates of hospitalizations for pediatric eating disorders by clinical and demographic characteristics in Ontario, Canada, over a 17-year period.Design, setting, and participantsThis population-based, repeated, cross-sectional study used linked health administrative and demographic databases in Ontario, Canada, to identify individuals aged 5 to 17 years hospitalized with eating disorder diagnoses from April 1, 2002, to March 31, 2020. Data analyses were performed from May 2021 to June 2023.ExposureFiscal year (April 1-March 31) of eating disorder hospitalization.Main outcomes and measuresOutcomes of interest were absolute and relative changes in pediatric eating disorder hospitalization rates overall and stratified by patient sex, age groups, and eating disorder diagnostic groups.ResultsOver the study period, there were 11 654 pediatric eating disorder hospitalizations, of which 5268 (45.2%) were for anorexia nervosa and 1374 (11.8%) were for bulimia nervosa. There were a total of 10 648 hospitalizations (91.4%) among female patients, and the median (IQR) age was 15.0 (14-0-16.0) years. Hospitalization rates increased 139% from 2002 to 2019, from 2.0 per 10 000 population to 4.8 per 10 000 population. The largest relative changes were observed among male patients (416%; from 0.2 per 10 000 population to 1.1 per 10 000 population), individuals aged 12 to 14 years (196%; from 2.2 per 10 000 population to 6.6 per 10 000 population), and individuals with eating disorders other than anorexia or bulimia nervosa (255%; from 0.6 per 10 000 population to 2.1 per 10 000 population). Male patients, younger adolescents, and individuals with other eating disorders also represented larger proportions of hospitalizations by fiscal 2019.Conclusions and relevanceIn this cross-sectional study of eating disorder hospitalizations, pediatric hospitalizations increased over time, particularly among populations traditionally considered atypical. Existing eating disorder programs must adapt to accommodate changing patient presentations and increased volumes to ensure effective care delivery.

Project description:BackgroundPeople with diabetes mellitus commonly experience hypoglycemia, but they may not necessarily present to hospital after severe hypoglycemia requiring paramedic assistance. We sought to describe the incidence and characteristics of calls for hypoglycemia requiring paramedic assistance among adults in southwestern Ontario, Canada, and to determine predictors of hospital transport.MethodsThis population-based retrospective cohort study used data extracted from ambulance call reports (ACRs) of 8 paramedic services of the Southwest Ontario Regional Base Hospital Program from January 2008 to June 2014. We described calls in which treatment for hypoglycemia was administered, summarized the incidence of hypoglycemia calls and performed logistic regression to determine predictors of hospital transport.ResultsOut of 470 467 ACRs during the study period, 9185 paramedic calls occurred in which hypoglycemia treatment was administered to an adult (mean age 60.2 yr, 56.8% male, 81.1% with documented diabetes). Refusal of hospital transport occurred in 2243 (24.4%) of calls. Documented diabetes diagnosis (adjusted odds ratio [OR] 0.82, 95% confidence interval [CI] 0.69-0.96), higher capillary blood glucose (adjusted OR 0.31, 95% CI 0.22-0.44) and overnight calls (adjusted OR 0.80, 95% CI 0.72-0.91) were associated with lower odds of hospital transport. Higher-acuity calls (adjusted OR 2.05, 95% CI 1.58-2.66) were associated with higher odds of transport. The estimated annual incidence rate of hypoglycemia requiring paramedic assistance was 108 per 10 000 people with diabetes per year.InterpretationHypoglycemia requiring paramedic assistance in southwestern Ontario is common, and close to 25% of calls do not result in hospital transport. Physicians managing diabetes care may be unaware of patients' hypoglycemia requiring paramedic care, suggesting a potential gap in follow-up care; we suggest that paramedics play an important role in identifying those at high recurrence risk and communicating with their care providers.

Project description:ObjectivesRegional variation in cancer survival is an important health system performance measurement. We evaluated if regional variation in colon cancer survival may be driven by differences in the patient population, their health and healthcare utilisation, and/or cancer care delivery.DesignPopulation-based retrospective cohort study using routinely collected linked health administrative data.SettingOntario, Canada.ParticipantsPatients with colon cancer diagnosed between 1 January 2009 and 31 December 2012.OutcomeCancer-specific survival was compared across the province's 14 health regions. Using accelerated failure time models, we assessed whether regional survival variations were mediated through differences in case mix, including age, sex, comorbidities, stage at diagnosis and colon subsite, potential marginalisation and/or prediagnosis healthcare.ResultsThe study population included 16 895 patients with colon cancer. There was statistically significant regional variation in cancer-specific survival. Three regions had cancer-specific survival that was between 30% (95% CI 1.03 to 1.65) and 39% (95% CI 1.13 to 1.71) longer and one region had cancer-specific survival that was 26% shorter (95% CI 0.58 to 0.93) than the reference region. For three of these regions, case mix explained between 26% and 56% of the survival variation. Further adjustment for rurality explained 22% of the remaining survival variation in one region. Adjustment for continuity of primary care and the diagnostic interval length explained 10% and 11% of the remaining survival variation in two other regions. Socioeconomic marginalisation, recent immigration and colonoscopy history did not explain colon cancer survival variation.ConclusionsCase mix accounted for much of the regional variation in colon cancer survival, indicating that efforts to monitor the quality of cancer care through survival metrics should consider case mix when reporting regional survival differences. Future work should repeat this approach in other settings and other cancer sites considering a broad range of potential mediators.

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SARS-CoV-2 infection among physicians over time in Ontario, Canada: a population-based retrospective cohort study

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