Rates of genetic consultation in high-grade serous ovarian cancer patients in the era of PARP inhibitor therapy: A population-based study.

OBJECTIVE: The American Society of Clinical Oncology recommends all patients with high-grade serous ovarian carcinoma (HGSC) undergo germline genetic testing. Genetic consultation rates in Ontario, Canada, only reached 13.3% in 2011. In 2016, PARP inhibitor maintenance therapy became available in Ontario for BRCA-positive HGSC patients. Given expanding treatment options, we re-examined genetic consultation rates among HGSC patients. METHODS: This retrospective cohort study identified patients diagnosed with HGSC between 2012 and 2019 using population-based administrative data from Ontario. Genetics consultations were identified using Ontario Health Insurance Plan billing codes. Consultation rates over time were analyzed using Cochran-Armitage trend test and segmental regression analysis. Multivariable analysis identified factors associated with attending genetics consultation. RESULTS: This study included 4645 HGSC patients. The mean age was 64.2 years (±SD 12.3); 56.3% had stage 3-4 disease. Overall, approximately 35% attended genetics consultations. The genetic consultation rate per year increased significantly from 21.6% to 42.6% (P < 0.001). Shorter times between diagnosis and genetics consult were observed after PARP inhibitors became available (68.1 vs 34.1 weeks, P < 0.001). Patients treated at designated cancer centers (odds ratio [OR] 2.11, P < 0.001), diagnosed in later years (OR 1.33, P < 0.001), and from higher income groups (P < 0.05) were more likely to attend genetics consultation; older patients were less likely (OR 0.98, P < 0.001). After PARP inhibitors became available, consultation rates plateaued (P < 0.001). CONCLUSIONS: Between 2012 and 2019, genetic consultation rates improved significantly among HGSC patients; however, a large proportion of patients never attended consultation. Further exploration of barriers to care is warranted to improve consultation rates and ensure equitable access to care.

A Population-Based Analysis of the Impact of the COVID-19 Pandemic on Solid Organ Transplantation in Ontario, Canada: Policy Response and Changes in Volume and 90-Day Outcomes.

Objectives: To evaluate the impact of the COVID-19 pandemic on solid organ transplantation. Background: COVID-19 caused unprecedented disruption to solid organ transplantation (kidney, liver, heart, lung). Concerns about safety and decreases in deceased donors due to pandemic lockdowns have been described as potential causes. Methods: We report population-based rates of transplantation during the first 3 waves of COVID-19 in Ontario, Canada (March 1, 2020-July 3, 2021) versus a pre-COVID-19 baseline period (January 1, 2017-February 29, 2020). Poisson models were used to predict transplantation rates during COVID-19, based on pre-COVID-19 rates, and generate observed to expected rate ratios (RRs). Ninety-day transplant outcomes (mortality, retransplantation, transplant nephrectomy) were captured. Results: A 34.4% decrease (RR, 0.656; 95% confidence interval [CI], 0.586-0.734) in transplant rates was observed, coinciding with wave 1 and the deployment of a provincial transplant triaging system. Transplants decreased by 14.6% in wave 2 (RR, 0.854; 95% CI, 0.770-0.947) and 23.1% in wave 3 (RR, 0.769; 95% CI, 0.690-0.857) despite the triaging system not being activated. Overall, there was a 24.3% decrease (RR, 0.757; 95% CI, 0.679-0.844) in transplant rates, equivalent to 409 fewer transplants. No sustained changes were observed in heart or liver but sustained and large decreases were seen for lung (RR, 0.664; 95% CI, 0.482-0.915) and kidney (RR, 0.721; 95% CI, 0.602-0.863) transplantation. A low prevalence (1.7%) of COVID-19 infection within 90 days of transplantation was seen. No differences were observed in other 90-day outcomes. Conclusions: Early safety concerns limited transplantation to immediate life-saving procedures; however, the reductions in kidney and lung transplants continued for the rest of the pandemic, where no restrictions were in place.

Self-Harm Events and Suicide Deaths Among Autistic Individuals in Ontario, Canada.

Importance: Reasons for elevated suicide risks among autistic people are unclear, with insufficient population-based research on sex-specific patterns to inform tailored prevention and intervention. Objectives: To examine sex-stratified rates of self-harm events and suicide death among autistic individuals compared with nonautistic individuals, as well as the associated sociodemographic and clinical risk factors. Design, Setting, and Participants: This population-based matched-cohort study using linked health administrative databases in Ontario, Canada included all individuals with physician-recorded autism diagnoses from April 1, 1988, to March 31, 2018, each matched on age and sex to 4 nonautistic individuals from the general population. Self-harm events resulting in emergency health care from April 1, 2005, to December 31, 2020, were examined for one cohort, and death by suicide and other causes from April 1, 1993, to December 31, 2018, were examined for another cohort. Statistical analyses were conducted between October 2021 and June 2023. Exposure: Physician-recorded autism diagnoses from 1988 to 2018 from health administrative databases. Main Outcomes and Measures: Autistic and nonautistic individuals who were sex stratified a priori were compared using Andersen-Gill recurrent event models on self-harm events, and cause-specific competing risk models on death by suicide or other causes. Neighborhood-level income and rurality indices, and individual-level broad diagnostic categories of intellectual disabilities, mood and anxiety disorders, schizophrenia spectrum disorders, substance use disorders, and personality disorders were covariates. Results: For self-harm events (cohort, 379 630 individuals; median age at maximum follow-up, 20 years [IQR, 15-28 years]; median age of first autism diagnosis claim for autistic individuals, 9 years [IQR, 4-15 years]; 19 800 autistic females, 56 126 autistic males 79 200 nonautistic females, and 224 504 nonautistic males), among both sexes, autism diagnoses had independent associations with self-harm events (females: relative rate, 1.83; 95% CI, 1.61-2.08; males: relative rate, 1.47; 95% CI, 1.28-1.69) after accounting for income, rurality, intellectual disabilities, and psychiatric diagnoses. For suicide death (cohort, 334 690 individuals; median age at maximum follow-up, 19 years [IQR, 14-27 years]; median age of first autism diagnosis claim for autistic individuals, 10 years [IQR, 5-16 years]; 17 982 autistic females, 48 956 autistic males, 71 928 nonautistic females, 195 824 nonautistic males), there was a significantly higher crude hazard ratio among autistic females (1.98; 95% CI, 1.11-3.56) and a nonsignificantly higher crude hazard ratio among autistic males (1.34; 95% CI, 0.99-1.82); the increased risks were associated with psychiatric diagnoses. Conclusions and Relevance: This cohort study suggests that autistic individuals experienced increased risks of self-harm events and suicide death. Psychiatric diagnoses were significantly associated with the increased risks among both sexes, especially for suicide death, and in partially sex-unique ways. Autism-tailored and autism-informed clinical and social support to reduce suicide risks should consider multifactorial mechanisms, with a particular focus on the prevention and timely treatment of psychiatric illnesses.

Changes in comprehensiveness of services delivered by Canadian family physicians: Analysis of population-based linked data in 4 provinces.

OBJECTIVE: To describe changes in the comprehensiveness of services delivered by family physicians across service settings and service areas in 4 Canadian provinces, to identify which settings and areas have changed the most, and to compare the magnitude of changes by physician characteristics. DESIGN: Descriptive analysis of province-wide, population-based billing data linked to population and physician registries. SETTING: British Columbia, Manitoba, Ontario, and Nova Scotia. PARTICIPANTS: Family physicians registered to practise in the 1999-2000 and 2017-2018 fiscal years. MAIN OUTCOME MEASURES: Comprehensiveness was measured across 7 service settings (home care, long-term care, emergency departments, hospitals, obstetric care, surgical assistance, anesthesiology) and in 7 service areas consistent with office-based practice (prenatal and postnatal care, Papanicolaou testing, mental health, substance use, cancer care, minor surgery, palliative home visits). The proportion of physicians with activity in each setting and area are reported and the average number of service settings and areas by physician characteristics is described (years in practice, sex, urban or rural practice setting, and location of medical degree training). RESULTS: Declines in comprehensiveness were observed across all provinces studied. Declines were greater for comprehensiveness of settings than for areas consistent with office-based practice. Changes were observed across all physician characteristics. On average across provinces, declines in the number of service settings and service areas were highest among physicians in practice 20 years or longer, male physicians, and physicians practising in urban areas. CONCLUSION: Declining comprehensiveness was observed across all physician characteristics, pointing to changes in the practice and policy contexts in which all family physicians work.

Declining Comprehensiveness of Services Delivered by Canadian Family Physicians Is Not Driven by Early-Career Physicians.

We describe changes in the comprehensiveness of services delivered by family physicians in 4 Canadian provinces (British Columbia, Manitoba, Ontario, Nova Scotia) during the periods 1999-2000 and 2017-2018 and explore if changes differ by years in practice. We measured comprehensiveness using province-wide billing data across 7 settings (home, long-term care, emergency department, hospital, obstetrics, surgical assistance, anesthesiology) and 7 service areas (pre/postnatal care, Papanicolaou [Pap] testing, mental health, substance use, cancer care, minor surgery, palliative home visits). Comprehensiveness declined in all provinces, with greater changes in number of service settings than service areas. Decreases were no greater among new-to-practice physicians.

Characterizing the Impact of Procedure Funding on the Covid-19 Generated Procedure Gap in Ontario: A Population-Based Analysis.

BACKGROUND: Surgical procedures in Canada were historically funded through global hospital budgets. Activity-based funding models were developed to improve access, equity, timeliness, and value of care for priority areas. COVID-19 upended health priorities and resulted in unprecedented disruptions to surgical care, which created a significant procedure gap. We hypothesized that activity-based funding models influenced the magnitude and trajectory of this procedure gap. METHODS: Population-based analysis of procedure rates comparing the pandemic (March 1, 2020-December 31, 2021) to a prepandemic baseline (January 1, 2017-February 29, 2020) in Ontario, Canada. Poisson generalized estimating equation models were used to predict expected rates in the pandemic based on the prepandemic baseline. Analyses were stratified by procedure type (outpatient, inpatient), body region, and funding category (activity-based funding programs vs. global budget). RESULTS: In all, 281,328 fewer scheduled procedures were performed during the COVID-19 period compared with the prepandemic baseline (Rate Ratio 0.78; 95% CI 0.77-0.80). Inpatient procedures saw a larger reduction (24.8%) in volume compared with outpatient procedures (20.5%). An increase in the proportion of procedures funded through activity-based programs was seen during the pandemic (52%) relative to the prepandemic baseline (50%). Body systems funded predominantly through global hospital budgets (eg, gynecology, otologic surgery) saw the least months at or above baseline volumes, whereas those with multiple activity-based funding options (eg, musculoskeletal, abdominal) saw the most months at or above baseline volumes. CONCLUSIONS: Those needing procedures funded through global hospital budgets may have been disproportionately disadvantaged by pandemic-related health care disruptions.

Maternal Schizophrenia and the Risk of a Childhood Chronic Condition.

BACKGROUND AND HYPOTHESIS: Maternal schizophrenia heightens the risk for certain perinatal complications, yet it is not known to what degree future childhood chronic health conditions (Childhood-CC) might arise. STUDY DESIGN: This population-based cohort study using health administrative data from Ontario, Canada (1995-2018) compared 5066 children of mothers with schizophrenia to 25 324 children of mothers without schizophrenia, propensity-matched on birth-year, maternal age, parity, immigrant status, income, region of residence, and maternal medical and psychiatric conditions other than schizophrenia. Cox proportional hazard models generated hazard ratios (HR) and 95% confidence intervals (CI) for incident Childhood-CCs, and all-cause mortality, up to age 19 years. STUDY RESULTS: Six hundred and fifty-six children exposed to maternal schizophrenia developed a Childhood-CC (20.5/1000 person-years) vs. 2872 unexposed children (17.1/1000 person-years)-an HR of 1.18, 95% CI 1.08-1.28. Corresponding rates were 3.3 vs. 1.9/1000 person-years (1.77, 1.44-2.18) for mental health Childhood-CC, and 18.0 vs. 15.7/1000 person-years (1.13, 1.04-1.24) for non-mental health Childhood-CC. All-cause mortality rates were 1.2 vs. 0.8/1000 person-years (1.34, 0.96-1.89). Risk for children exposed to maternal schizophrenia was similar whether or not children were discharged to social service care. From age 1 year, risk was greater for children whose mothers were diagnosed with schizophrenia prior to pregnancy than for children whose mothers were diagnosed with schizophrenia postnatally. CONCLUSIONS: A child exposed to maternal schizophrenia is at elevated risk of chronic health conditions including mental and physical subtypes. Future research should examine what explains the increased risk particularly for physical health conditions, and what preventive and treatment efforts are needed for these children.

The Use of Cremation Data for Timely Mortality Surveillance During the COVID-19 Pandemic in Ontario, Canada: Validation Study.

BACKGROUND: Early estimates of excess mortality are crucial for understanding the impact of COVID-19. However, there is a lag of several months in the reporting of vital statistics mortality data for many jurisdictions, including across Canada. In Ontario, a Canadian province, certification by a coroner is required before cremation can occur, creating real-time mortality data that encompasses the majority of deaths within the province. OBJECTIVE: This study aimed to validate the use of cremation data as a timely surveillance tool for all-cause mortality during a public health emergency in a jurisdiction with delays in vital statistics data. Specifically, this study aimed to validate this surveillance tool by determining the stability, timeliness, and robustness of its real-time estimation of all-cause mortality. METHODS: Cremation records from January 2020 until April 2021 were compared to the historical records from 2017 to 2019, grouped according to week, age, sex, and whether COVID-19 was the cause of death. Cremation data were compared to Ontario's provisional vital statistics mortality data released by Statistics Canada. The 2020 and 2021 records were then compared to previous years (2017-2019) to determine whether there was excess mortality within various age groups and whether deaths attributed to COVID-19 accounted for the entirety of the excess mortality. RESULTS: Between 2017 and 2019, cremations were performed for 67.4% (95% CI 67.3%-67.5%) of deaths. The proportion of cremated deaths remained stable throughout 2020, even within age and sex categories. Cremation records are 99% complete within 3 weeks of the date of death, which precedes the compilation of vital statistics data by several months. Consequently, during the first wave (from April to June 2020), cremation records detected a 16.9% increase (95% CI 14.6%-19.3%) in all-cause mortality, a finding that was confirmed several months later with cremation data. CONCLUSIONS: The percentage of Ontarians cremated and the completion of cremation data several months before vital statistics did not change meaningfully during the COVID-19 pandemic period, establishing that the pandemic did not significantly alter cremation practices. Cremation data can be used to accurately estimate all-cause mortality in near real-time, particularly when real-time mortality estimates are needed to inform policy decisions for public health measures. The accuracy of this excess mortality estimation was confirmed by comparing it with official vital statistics data. These findings demonstrate the utility of cremation data as a complementary data source for timely mortality information during public health emergencies.

A Population-based Analysis of the COVID-19 Generated Surgical Backlog and Associated Emergency Department Presentations for Inguinal Hernias and Gallstone Disease.

OBJECTIVE: To evaluate the downstream effects of the COVID-19 generated surgical backlog. BACKGROUND: Delayed elective surgeries may result in emergency department (ED) presentations and the need for urgent interventions. METHODS: Population-based repeated cross-sectional study utilizing administrative data. We quantified rates of elective cholecystectomy and inguinal hernia repair and rates of ED presentations, urgent interventions, and outcomes during the first and second waves of COVID-19 (March 1, 2020- February 28, 2021) as compared to a 3-year pre-COVID-19 period (January 1, 2017-February 29, 2020) in Ontario, Canada. Poisson generalized estimating equation models were used to predict expected rates during COVID-19 based on the pre-COVID-19 period. The ratio of observed (actual events) to expected rates was generated for surgical procedures (SRRs) and ED visits (ED-RRs). RESULTS: We identified 74,709 elective cholecystectomies and 60,038 elective inguinal hernia repairs. During the COVID-19 period, elective inguinal hernia repairs decreased by 21% (SRR 0.791; 0.760-0.824) whereas elective cholecystectomies decreased by 23% (SRR 0.773; 0.732-0.816). ED visits for inguinal hernia decreased by 17% (ED-RR 0.829; 0.786 - 0.874) whereas ED visits for gallstones decreased by 8% (ED-RR 0.922; 0.878 - 0.967). A higher population rate of urgent cholecystectomy was observed, particularly after the first wave (SRR 1.076; 1.000-1.158). No difference was seen in inguinal hernias. CONCLUSIONS: An over 20% reduction in elective surgeries and an increase in urgent cholecystectomies was observed during the COVID-19 period suggesting a rebound effect secondary to the surgical backlog. The COVID-19 generated surgical backlog will have a heterogeneous downstream effect with significant implications for surgical recovery planning.

A Population-Based Analysis of Diabetes-Related Care Measures, Foot Complications, and Amputation During the COVID-19 Pandemic in Ontario, Canada.

Importance: Deferred diabetic foot screening and delays in timely care of acute foot complications during the COVID-19 pandemic may have contributed to an increase in limb loss. Objective: To evaluate the association of the COVID-19 pandemic with diabetes-related care measures, foot complications, and amputation. Design, Setting, and Participants: This population-based cohort study included all adult residents of Ontario, Canada, with diabetes and compared the rates of selected outcomes from January 1, 2020, to February 23, 2021, vs January 1, 2019, to February 23, 2020. Main Outcomes and Measures: Comprehensive in-person diabetes care assessment, including foot examination; hemoglobin A1c (HbA1c) measurement; emergency department visit or hospitalization for diabetic foot ulceration, osteomyelitis, or gangrene; lower extremity open or endovascular revascularization; minor (toe or partial-foot) amputation; and major (above-ankle) leg amputation. Rates and rate ratios (RRs) comparing 2020-2021 vs 2019-2020 for each measure were calculated for 10-week periods, anchored relative to onset of the pandemic on March 11, 2020 (11th week of 2020). Results: On March 11, 2020, the study included 1 488 605 adults with diabetes (median [IQR] age, 65 [55-74] years; 776 665 [52.2%] men), and on March 11, 2019, the study included 1 441 029 adults with diabetes (median [IQR] age, 65 [55-74] years; 751 459 [52.1%] men). After the onset of the pandemic, rates of major amputation in 2020-2021 decreased compared with 2019-2020 levels. The RR for the prepandemic period from January 1 to March 10 was 1.05 (95% CI, 0.88-1.25), with RRs in the pandemic periods ranging from 0.86 (95% CI, 0.72-1.03) in May 20 to July 28 to 0.95 (95% CI, 0.80-1.13) in October 7 to December 15. There were no consistent differences in demographic characteristics or comorbidities of patients undergoing amputation in the 2020-2021 vs 2019-2020 periods. Rates of comprehensive in-person diabetes care assessment and HbA1c measurement declined sharply and remained below 2019-2020 levels (eg, in-person assessment, March 11 to May 19: RR, 0.28; 95% CI, 0.28-0.28). The rates of emergency department visits (eg, March 11 to May 19: RR, 0.67; 95% CI, 0.61-0.75), hospitalization (eg, March 11 to May 19: RR, 0.77; 95% CI, 0.68-0.87), open revascularization (eg, March 11 to May 19: RR, 0.66; 95% CI, 0.56-0.79), endovascular revascularization (March 11 to May 19: RR, 0.70; 95% CI, 0.61-0.81), and minor amputation (March 11 to May 19: RR, 0.70; 95% CI, 0.60-0.83) initially dropped but recovered to 2019-2020 levels over the study period. Conclusions and Relevance: In this population-based cohort study, disruptions in care related to the COVID-19 pandemic were not associated with excess leg amputations among people living with diabetes. As the pandemic ends, improved prevention and treatment of diabetic foot complications will be necessary to maintain these positive results.

Asthma Severity and Control and Their Association With Perinatal Mental Illness.

OBJECTIVE: Growing evidence suggests asthma increases perinatal mental illness risk, but few studies have explored the impact of asthma severity and control. Our objective was to explore the association between asthma severity and control and perinatal mental illness risk and the impact of asthma exacerbations during pregnancy on postpartum mental illness risk. METHODS: This was a population-based retrospective cohort study of all women in Ontario, Canada, from 2005 to 2015 with a singleton live birth who used public drug insurance, excluding women with recent history of mental illness. We constructed modified Poisson regression models to assess the risk of perinatal mental illness, defined as a mood or anxiety, psychotic or substance use disorder, self-harm or other mental illness diagnosed from conception to 365 days postnatally. Models controlled for socio-demographic factors and medical history. RESULTS: There were 62,583 women in the cohort (46.7% between 15 - 24 years), of whom 22.7% had asthma (94.3% mild, 5.7% moderate/severe; 86.5% controlled and 13.5% uncontrolled). After adjustment, there was increased risk of perinatal mental illness with mild asthma (adjusted relative risk [RR]: 1.12; 95% confidence interval [CI], 1.09 to 1.16) and moderate/severe asthma (aRR: 1.16; 95% CI, 1.04 to 1.30) compared to no asthma. Controlled asthma (aRR: 1.11; 95% CI, 1.08 to 1.15) and uncontrolled asthma (aRR: 1.19; 95% CI, 1.11 to 1.27) were also associated with increased perinatal mental illness risk compared to no asthma. Women with worsened asthma during pregnancy had the highest risk of postpartum mental illness compared to no change in asthma status (by severity: aRR: 1.57; 95% CI, 1.36 to 1.80; by control: aRR: 1.37; 95% CI, 1.22 to 1.54). CONCLUSION: Asthma is associated with increased risk of perinatal mental illness, particularly in the presence of asthma exacerbations in pregnancy. The results support multidisciplinary collaborative care programmes throughout the perinatal period, especially among women with asthma exacerbations during pregnancy.

Morbidity and mortality reduction associated with polysomnography testing in idiopathic pulmonary fibrosis: a population-based cohort study.

BACKGROUND: It is not well-known if diagnosing and treating sleep breathing disorders among individuals with idiopathic pulmonary fibrosis (IPF) improves health outcomes. We evaluated the association between receipt of laboratory-based polysomnography (which is the first step in the diagnosis and treatment of sleep breathing disorders in Ontario, Canada) and respiratory-related hospitalization and all-cause mortality among individuals with IPF. METHODS: We used a retrospective, population-based, cohort study design, analyzing health administrative data from Ontario, Canada, from 2007 to 2019. Individuals with IPF were identified using an algorithm based on health administrative codes previously developed by IPF experts. Propensity score matching was used to account for potential differences in 41 relevant covariates between individuals that underwent polysomnography (exposed) and individuals that did not undergo polysomnography (controls), in order minimize potential confounding. Respiratory-related hospitalization and all-cause mortality were evaluated up to 12 months after the index date. RESULTS: Out of 5044 individuals with IPF identified, 201 (4.0%) received polysomnography, and 189 (94.0%) were matched to an equal number of controls. Compared to controls, exposed individuals had significantly reduced rates of respiratory-related hospitalization (hazard ratio [HR] 0.43, 95% confidence interval [CI] 0.24-0.75), p = 0.003) and all-cause mortality (HR 0.49, 95% CI 0.30-0.80), p = 0.004). Significantly reduced rate of respiratory-related hospitalization (but not all-cause mortality) was also observed among those with > = 1 respiratory-related hospitalization (HR 0.38, 95% CI 0.15-0.99) and systemic corticosteroid receipt (HR 0.37, 95% CI 0.19-0.94) in the year prior to the index date, which reflect sicker subgroups of persons. CONCLUSIONS: Undergoing polysomnography was associated with significantly improved clinically-important health outcomes among individuals with IPF, highlighting the potential importance of incorporating this testing in IPF disease management.

A population-based analysis of the impact of the COVID-19 pandemic on common abdominal and gynecological emergency department visits.

BACKGROUND: Reduced use of the emergency department during the COVID-19 pandemic may result in increased disease acuity when patients do seek health care services. We sought to evaluate emergency department visits for common abdominal and gynecologic conditions before and at the beginning of the pandemic to determine whether changes in emergency department attendance had serious consequences for patients. METHODS: We conducted a population-based analysis using administrative data to evaluate the weekly rate of emergency department visits pre-COVID-19 (Jan. 1-Mar. 10, 2020) and during the beginning of the COVID-19 pandemic (Mar. 11-June 30, 2020), compared with a historical control period (Jan. 1-July 1, 2019). All residents of Ontario, Canada, presenting to the emergency department with appendicitis, cholecystitis, ectopic pregnancy or miscarriage were included. We evaluated weekly incidence rate ratios (IRRs) of emergency department visits, management strategies and clinical outcomes. RESULTS: Across all study periods, 39 691 emergency department visits met inclusion criteria (40.2 % appendicitis, 32.1% miscarriage, 21.3% cholecystitis, 6.4% ectopic pregnancy). Baseline characteristics of patients presenting to the emergency department did not vary across study periods. After an initial reduction in emergency department visits, presentations for cholecystitis and ectopic pregnancy quickly returned to expected levels. However, presentations for appendicitis and miscarriage showed sustained reductions (IRR 0.61-0.80), with 1087 and 984 fewer visits, respectively, after the start of the pandemic, relative to 2019. Management strategies, complications and mortality rates were similar across study periods for all conditions. INTERPRETATION: Although our study showed evidence of emergency department avoidance in Ontario during the first wave of the COVID-19 pandemic, no adverse consequences were evident. Emergency care and outcomes for patients were similar before and during the pandemic.

Ethnic and Immigrant Variations in the Time Trends of Dementia and Parkinsonism.

OBJECTIVE: We assessed long-term incidence and prevalence trends of dementia and parkinsonism across major ethnic and immigrant groups in Ontario. METHODS: Linking administrative databases, we established two cohorts (dementia 2001-2014 and parkinsonism 2001-2015) of all residents aged 20 to 100 years with incident diagnosis of dementia (N = 387,937) or parkinsonism (N = 59,617). We calculated age- and sex-standardized incidence and prevalence of dementia and parkinsonism by immigrant status and ethnic groups (Chinese, South Asian, and the General Population). We assessed incidence and prevalence trends using Poisson regression and Cochran-Armitage trend tests. RESULTS: Across selected ethnic groups, dementia incidence and prevalence were higher in long-term residents than recent or longer-term immigrants from 2001 to 2014. During this period, age- and sex-standardized incidence of dementia in Chinese, South Asian, and the General Population increased, respectively, among longer-term immigrants (by 41%, 58%, and 42%) and long-term residents (28%, 7%, and 4%), and to a lesser degree among recent immigrants. The small number of cases precluded us from assessing parkinsonism incidence trends. For Chinese, South Asian, and the General Population, respectively, prevalence of dementia and parkinsonism modestly increased over time among recent immigrants but significantly increased among longer-term immigrants (dementia: 134%, 217%, and 117%; parkinsonism: 55%, 54%, and 43%) and long-term residents (dementia: 97%, 132%, and 71%; parkinsonism: 18%, 30%, and 29%). Adjustment for pre-existing conditions did not appear to explain incidence trends, except for stroke and coronary artery disease as potential drivers of dementia incidence. CONCLUSION: Recent immigrants across major ethnic groups in Ontario had considerably lower rates of dementia and parkinsonism than long-term residents, but this difference diminished with longer-term immigrants.

Palivizumab's real-world effectiveness: a population-based study in Ontario, Canada, 1993-2017.

OBJECTIVE: To evaluate the effectiveness of two palivizumab programmes targeting high-risk infants, defined by prematurity, diagnosis of comorbidities and geography, and assess potential disparities by neighbourhood income. DESIGN: Controlled, interrupted time series. SETTING: Ontario, Canada. PATIENTS: We used linked health and demographic administrative databases to identify all children born in hospitals 1 January 1993 through 31 December 2016. Follow-up ended at the earliest of second birthday or 30 June 2017. INTERVENTION: Palivizumab-eligibility: child was born very preterm and ≤6 months old during respiratory syncytial virus (RSV) season; <24 months old with significant chronic lung or congenital heart disease; or ≤6 months, born preterm or residents of remote regions. MAIN OUTCOME: Severe RSV-related illness, defined as hospitalisation or death with a diagnosis of bronchiolitis, RSV pneumonia or RSV. RESULTS: 3 million births and 87 000 RSV-related events were identified. Over the study period, rates of severe RSV-related illness declined 65.4% among the highest risk group, eligible infants <6 months (230.6 to 79.8 admissions per 1000 child-years). Relative to changes among ineligible infants <6 months, rates dropped 10.4% (95% CI -18.6% to 39.4%) among eligible infants immediately following introduction of a national palivizumab programme in 1998. Initially, rates were considerably higher among infants from low-income neighbourhoods, but income-specific rates converged over time among eligible infants <6 months; such convergence was not seen among other children. CONCLUSIONS: Incidence of severe RSV-related illness declined over the study period. While we cannot attribute causality, the timing and magnitude of these declines suggest impact of palivizumab in reducing RSV burden and diminishing social inequities among palivizumab-eligible infants.

Development and validation of a simple algorithm to estimate common gestational age categories using standard administrative birth record data in Ontario, Canada.

Gestational age is often incompletely recorded in administrative records, despite being critical to paediatric and maternal health research. Several algorithms exist to estimate gestational age using administrative databases; however, many have not been validated or use complicated methods that are not readily adaptable. We developed a simple algorithm to estimate common gestational age categories from routine administrative data. We leveraged a population-based registry of all hospital births occurring in Ontario, Canada over 2002-2016 including 1.8 million birth records. In this sample, this simple algorithm had excellent performance compared to a verified measure of gestational age; 87.61% agreement (95% CI: 87.49, 87.74). The accuracy of the algorithm exceeded 98% for all of the gestational age categories. Agreement notably increased over time and was greatest among singleton births and infants born at 2500-2999 g. This study provides a straight-forward algorithm for accurately estimating common gestational age categories that is easily adaptable for use in other countries.Impact StatementWhat is already known on this subject? Gestational age is often incompletely or inaccurately recorded in administrative health databases, despite being critical to the study of many paediatric and maternal health outcomes. Consequently, researchers must rely on various methods to estimate gestational age, many of these methods are either overly simple (i.e. assuming a uniform duration) or analytically complicated and difficult to adapt for new populations (e.g. regression-based approaches).What the results of this study add? This study, based on a population-based registry of all 1.8 million births occurring in Ontario, Canada 2003-2016, found that a simple, sex-specific algorithm using three commonly recorded birth record characteristics performs almost perfectly compared to a clinical estimate recorded near birth.What the implications are of these findings for clinical practice and/or further research? This study suggests that a straight-forward, sex-specific algorithm based on routinely collected birth record data is able to accurately estimate common gestational age categories (i.e. extreme preterm, <28 weeks; very preterm, 28-32 weeks; moderate-to-late preterm, 33-26 weeks; and term, 37 weeks of completed gestational age). This work will be of greatest interest to perinatal researchers using routinely collected health administrative data.

Smoking patterns based on birth-cohort-specific histories from 1965 to 2013, with projections to 2041.

BACKGROUND: Characterizing smoking patterns over time is essential for evaluating the impact of tobacco control interventions and predicting smoking-related mortality. Beginning with a 1920s birth cohort, smoking histories (i.e., estimates of smoking initiation and cessation, and prevalence of current and former smokers) were generated. DATA: The Ontario sample (n = 238,411) of the 2003 to 2013 cycles of the Canadian Community Health Survey, which is conducted biennially, was used to obtain cross-sectional information on current smoking behaviour. METHODS: Age at smoking initiation and age at smoking cessation were used to construct smoking histories for each respondent, up to the survey date. An age-period-cohort model was generated and used to examine survival differences by smoking status. Using the model, and adjusting for survival differences in smoking status, the prevalence of current, former and never smokers was estimated in cohorts from 1920 to 1985. Smoking initiation, cessation and intensity were then estimated for age-specific distributions of each birth cohort. These rates were projected forward through to 2041. Smoking patterns by highest level of education were generated using education-stratified models. RESULTS: Smoking histories show clear trends over time by sex, cohort and age. If current patterns persist, smoking prevalence is projected to decline to single digits (below 10%) by 2023 for women and 2040 for men. DISCUSSION: Birth-cohort-specific smoking histories can be generated using cross-sectional health surveys. These cohort histories can describe smoking patterns over time and into the future. In turn, these histories can be used in micro-simulation models to evaluate historic or planned tobacco control interventions, and to project smoking prevalence.

Assessing the completeness of infant and childhood immunizations within a provincial registry populated by parental reporting: A study using linked databases in Ontario, Canada.

INTRODUCTION: In Ontario, Canada, parents have the responsibility to report their child's routine infant and childhood vaccines to the provincial immunization registry (the Digital Health Immunization Repository; DHIR) without healthcare provider validation. Despite its use in routine immunization coverage monitoring, no study has previously examined the completeness of immunization data within the DHIR. METHODS: We assessed the completeness of DHIR immunizations, as compared to immunizations within the Electronic Medical Records-Primary Care (EMRPC) database, also known as EMRALD, a network of family physician electronic medical records (EMRs). We linked client records from the DHIR and EMRPC to a centralized population file. To create the study cohort, we examined children born during 2005-2008 and further defined the cohort based on those rostered to an EMRPC physician, visit criteria to ensure ongoing care by an EMRPC provider, and school attendance in Ontario at age 7. We calculated up-to-date (UTD) immunization coverage at age 7 for individual vaccines and overall using data from the DHIR and EMRPC separately, and compared the estimates. RESULTS: The analytic cohort to assess DHIR data completeness included 2,657 children. Overall UTD coverage (all vaccines assessed) was 82.0% in the DHIR and 67.6% in EMRPC. UTD coverage was higher in the DHIR for all vaccines assessed individually, with the exception of meningococcal C conjugate vaccine (difference = 0.3%). After excluding two EMRPC sites with irregularities in immunization data, the difference in overall UTD coverage between systems decreased from 14.4% to 6.6% INTERPRETATION: These results validate the use of DHIR for coverage assessment but also suggest that bidirectional exchange of immunization information has the potential to increase immunization data completeness in both systems.