An individual-based dynamic model to assess interventions to mitigate opioid overdose risk.

BACKGROUND: Illicit opioid overdose continues to rise in North America and is a leading cause of death. Mathematical modeling is a valuable tool to investigate the epidemiology of this public health issue, as it can characterize key features of population outcomes and quantify the broader effect of structural and interventional changes on overdose mortality. The aim of this study is to quantify and predict the impact of key harm reduction strategies at differing levels of scale-up on fatal and nonfatal overdose among a population of people engaging in unregulated opioid use in Toronto. METHODS: An individual-based model for opioid overdose was built featuring demographic and behavioural variation among members of the population. Key individual attributes known to scale the risk of fatal and nonfatal overdose were identified and incorporated into a dynamic modeling framework, wherein every member of the simulated population encompasses a set of distinct characteristics that govern demographics, intervention usage, and overdose incidence. The model was parametrized to fatal and nonfatal overdose events reported in Toronto in 2019. The interventions considered were opioid agonist therapy (OAT), supervised consumption sites (SCS), take-home naloxone (THN), drug-checking, and reducing fentanyl in the drug supply. Harm reduction scenarios were explored relative to a baseline model to examine the impact of each intervention being scaled from 0% use to 100% use on overdose events. RESULTS: Model simulations resulted in 3690.6 nonfatal and 295.4 fatal overdoses, coinciding with 2019 data from Toronto. From this baseline, at full scale-up, 290 deaths were averted by THN, 248 from eliminating fentanyl from the drug supply, 124 from SCS use, 173 from OAT, and 100 by drug-checking services. Drug-checking and reducing fentanyl in the drug supply were the only harm reduction strategies that reduced the number of nonfatal overdoses. CONCLUSIONS: Within a multi-faceted harm reduction approach, scaling up take-home naloxone, and reducing fentanyl in the drug supply led to the largest reduction in opioid overdose fatality in Toronto. Detailed model simulation studies provide an additional tool to assess and inform public health policy on harm reduction.

Interobserver Variability of Coronary Stenosis Characterized by Coronary Angiography: A Single-Center (Toronto General Hospital) Retrospective Chart Review by Staff Cardiologists.

Introduction: The reliability of interpretation of coronary angiography as a diagnostic tool was investigated. Furthermore, the impact of interobserver variability of coronary lesions on clinical decision-making was assessed. One of our motivations to do this research was the research gaps and our aim to have up-to-date information regarding interobserver variability among different cardiologists. Methods: Our objective was to quantify interobserver variability among cardiologists who have seen angiograms independently. Disagreement among cardiologists in the visual assessment of invasive coronary angiography of coronary artery stenosis is not uncommon in previous studies. Three cardiologists with extensive experience in coronary angiography, including the primary cardiologist of each patient, read the angiograms of 200 patients from Toronto General Hospital independently. Results: Our research showed the mean agreement among all participating observers was 77.4%; therefore, the interobserver variability of coronary angiography interpretation was 22.6%. Discussion: Coronary angiography is still the gold-standard technique for guidance regarding coronary lesions. Sometimes, coronary angiography results in underestimation or overestimation of a lesion's functional severity. Interobserver variability should also be considered when interpreting the severity of coronary stenoses via invasive coronary angiography. This research shows that interobserver variability regarding coronary angiograms is still present (22.6%).

Plain language summary: The gold-standard method for diagnosing coronary stenosis, invasive coronary angiography has some challenges too. One of these challenges has been the difference among various cardiologists regarding determination of severity of each coronary stenosis. In this study, we focused on differences in interobserver variability in coronary angiography interpretation. Three cardiologists who were experienced in coronary angiography read each patient's coronary angiogram separately. Overall, 200 patients with a history of angiography at Toronto General Hospital were selected randomly. The research showed that overall agreement among all participating cardiologists with regard to the reading of coronary angiograms was 77.4%. In other words, interobserver variability of 22.6% was seen among the readers.

"I do think that accessibility is a really major thing that has come [out] of [the] pandemic": The lived experiences of resilience and health-related quality of life among a diverse sample of graduate students during the COVID-19 pandemic.

The COVID-19 pandemic has negatively impacted the mental health and wellbeing of post-secondary students. Resilience has been found to serve as a protective factor against mental distress among students during the pandemic. Despite the plethora of research that exists on post-secondary students during this crisis, most studies exploring students' health and resilience are quantitative and lack diversity. To date, the lived experiences of health-related quality of life (HRQOL) and resilience among graduate students representing diversity in age, gender, ethnicity, parental status, university, degree, and faculty during the COVID-19 pandemic remain unknown. As a part of a larger study, the purpose of this qualitative paper was to understand the lived experiences of resilience and HRQOL among a diverse sample of graduate students approximately 18 months into the COVID-19 pandemic in Ontario, Canada. A total of 14 students participated in semi-structured interviews exploring HRQOL domains, factors that supported/undermined participants' resilience, challenges/barriers to being resilient, and participants' inner strength. Thematic analysis revealed 5 themes: (1) cultural influences on resilience; (2) the role of privilege/power in shaping resilience; (3) how life stage and past experiences support resilience; (4) how the COVID-19 pandemic has undermined the resilience of equity-deserving groups; and (5) the role of disability/chronic pain. This work presents a unique dichotomy between how the COVID-19 pandemic has disrupted the lives of some graduate students, while simultaneously creating opportunities for others to thrive. Findings from this work underscore the importance of creating inclusive and accessible educational spaces to support graduate students' resilience and HRQOL currently, and in times of crisis.

Income differences in time to colon cancer diagnosis.

INTRODUCTION: People with low income have worse outcomes throughout the cancer care continuum; however, little is known about income and the diagnostic interval. We described diagnostic pathways by neighborhood income and investigated the association between income and the diagnostic interval. METHODS: This was a retrospective cohort study of colon cancer patients diagnosed 2007-2019 in Ontario using routinely collected data. The diagnostic interval was defined as the number of days from the first colon cancer encounter to diagnosis. Asymptomatic pathways were defined as first encounter with a colonoscopy or guaiac fecal occult blood test not occurring in the emergency department and were examined separately from symptomatic pathways. Quantile regression was used to determine the association between neighborhood income quintile and the conditional 50th and 90th percentile diagnostic interval controlling for age, sex, rural residence, and year of diagnosis. RESULTS: A total of 64,303 colon cancer patients were included. Patients residing in the lowest income neighborhoods were more likely to be diagnosed through symptomatic pathways and in the emergency department. Living in low-income neighborhoods was associated with longer 50th and 90th-percentile symptomatic diagnostic intervals compared to patients living in the highest income neighborhoods. For example, the 90th percentile diagnostic interval was 15 days (95% CI 6-23) longer in patients living in the lowest income neighborhoods compared to the highest. CONCLUSION: These findings reveal income inequities during the diagnostic phase of colon cancer. Future work should determine pathways to reducing inequalities along the diagnostic interval and evaluate screening and diagnostic assessment programs from an equity perspective.

The association between rurality, places of care and the location of death of long-term care home residents with dementia: A population-based study.

Background: Most individuals prefer to spend their final moments of life outside a hospital setting. This study compares the places of care and death of long-term care (LTC) home residents in Ontario in the last 90 days of life, according to LTC home rurality. Data and methods: This retrospective cohort study was conducted using health administrative data from ICES (formerly known as the Institute for Clinical Evaluative Sciences). The study population, which was identified through algorithms, included all Ontario LTC home residents with a dementia diagnosis who died between April 1, 2014, and March 31, 2019. The location of death was categorized as in an acute care hospital, an LTC home, a subacute care facility, or the community. Places of care included emergency department visits and hospitalizations in the last 90 days of life. Statistical tests were used to evaluate differences in location of death and places of care by rurality. Results: Of the 65,375 LTC home residents with dementia, 49,432 (75.6%) died in an LTC home. Residents of LTC homes in the most urban areas were less likely to die in an LTC home than those in more rural homes (adjusted relative risk: 0.84; 95% confidence interval: 0.83 to 0.85). A higher proportion of residents of the most urban LTC homes had at least one hospitalization in the last 90 days of life compared with rural residents (23.7% versus 9.9% palliative hospitalizations and 28.3% versus 15.9% non-palliative hospitalizations [p ⟨ 0.001]). Interpretation: Individuals with dementia residing in urban LTC homes are more likely to receive care in the hospital and to die outside a LTC home than their counterparts living in rural LTC homes. The findings of this work will inform efforts to improve end-of-life care for older adults with dementia living in LTC homes.

Effect modification by statin use status on the association between fine particulate matter (PM2.5) and cardiovascular mortality.

BACKGROUND: Numerous studies have linked fine particulate matter (PM2.5) to increased cardiovascular mortality. Less is known how the PM2.5-cardiovascular mortality association varies by use of cardiovascular medications. This study sought to quantify effect modification by statin use status on the associations between long-term exposure to PM2.5 and mortality from any cardiovascular cause, coronary heart disease (CHD), and stroke. METHODS: In this nested case-control study, we followed 1.2 million community-dwelling adults aged ≥66 years who lived in Ontario, Canada from 2000 through 2018. Cases were patients who died from the three causes. Each case was individually matched to up to 30 randomly selected controls using incidence density sampling. Conditional logistic regression models were used to estimate odds ratios (ORs) for the associations between PM2.5 and mortality. We evaluated the presence of effect modification considering both multiplicative (ratio of ORs) and additive scales (the relative excess risk due to interaction, RERI). RESULTS: Exposure to PM2.5 increased the risks for cardiovascular, CHD, and stroke mortality. For all three causes of death, compared with statin users, stronger PM2.5-mortality associations were observed among non-users [e.g. for cardiovascular mortality corresponding to each interquartile range increase in PM2.5, OR = 1.042 (95% CI, 1.032-1.053) vs OR = 1.009 (95% CI, 0.996-1.022) in users, ratio of ORs = 1.033 (95% CI, 1.019-1.047), RERI = 0.039 (95% CI, 0.025-0.050)]. Among users, partially adherent users exhibited a higher risk of PM2.5-associated mortality than fully adherent users. CONCLUSIONS: The associations of chronic exposure to PM2.5 with cardiovascular and CHD mortality were stronger among statin non-users compared to users.

Timing of follow-up visits after hospital discharge for COPD: Application of a new method.

RATIONALE: A common strategy to reduce COPD readmissions is to encourage patient follow-up with a physician within 1 to 2 weeks of discharge, yet evidence confirming its benefit is lacking. We used a new study design called target randomized trial emulation to determine the impact of follow-up visit timing on patient outcomes. METHODS: All Ontario residents aged 35 or older discharged from a COPD hospitalization were identified using health administrative data and randomly assigned to those who received and did not receive physician visit follow-up by within seven days. They were followed to all-cause emergency department visits, readmissions or death. Targeted randomized trial emulation was used to adjust for differences between the groups. COPD emergency department visits, readmissions or death was also considered. RESULTS: There were 94,034 patients hospitalized with COPD, of whom 73.5% had a physician visit within 30 days of discharge. Adjusted hazard ratio for all-cause readmission, emergency department visits or death for people with a visit within seven days post discharge was 1.03 (95% Confidence Interval [CI]: 1.01-1.05) and remained around 1 for subsequent days; adjusted hazard ratio for the composite COPD events was 0.97 (95% CI 0.95-1.00) and remained significantly lower than 1 for subsequent days. CONCLUSION: While a physician visit after discharge was found to reduce COPD events, a specific time period when a physician visit was most beneficial was not found. This suggests that follow-up visits should not occur at a predetermined time but be based on factors such as anticipated medical need.

Prenatal Exposure to Ambient Air Pollution and Cerebral Palsy.

Importance: Air pollution is associated with structural brain changes, disruption of neurogenesis, and neurodevelopmental disorders. The association between prenatal exposure to ambient air pollution and risk of cerebral palsy (CP), which is the most common motor disability in childhood, has not been thoroughly investigated. Objective: To evaluate the associations between prenatal residential exposure to ambient air pollution and risk of CP among children born at term gestation in a population cohort in Ontario, Canada. Design, Setting, and Participants: Population-based cohort study in Ontario, Canada using linked, province-wide health administrative databases. Participants were singleton full term births (≥37 gestational weeks) born in Ontario hospitals between April 1, 2002, and March 31, 2017. Data were analyzed from January to December 2022. Exposures: Weekly average concentrations of ambient fine particulate matter with a diameter 2.5 µm (PM2.5) or smaller, nitrogen dioxide (NO2), and ozone (O3) during pregnancy assigned by maternal residence reported at delivery from satellite-based estimates and ground-level monitoring data. Main outcome and measures: CP cases were ascertained by a single inpatient hospitalization diagnosis or at least 2 outpatient diagnoses for children from birth to age 18 years. Results: The present study included 1 587 935 mother-child pairs who reached term gestation, among whom 3170 (0.2%) children were diagnosed with CP. The study population had a mean (SD) maternal age of 30.1 (5.6) years and 811 745 infants (51.1%) were male. A per IQR increase (2.7 µg/m3) in prenatal ambient PM2.5 concentration was associated with a cumulative hazard ratio (CHR) of 1.12 (95% CI, 1.03-1.21) for CP. The CHR in male infants (1.14; 95% CI, 1.02-1.26) was higher compared with the CHR in female infants (1.08; 95% CI, 0.96-1.22). No specific window of susceptibility was found for prenatal PM2.5 exposure and CP in the study population. No associations or windows of susceptibility were found for prenatal NO2 or O3 exposure and CP risk. Conclusions and relevance: In this large cohort study of singleton full term births in Canada, prenatal ambient PM2.5 exposure was associated with an increased risk of CP in offspring. Further studies are needed to explore this association and its potential biological pathways, which could advance the identification of environmental risk factors of CP in early life.

Adherence to guideline-recommended care of late-onset hypertension in females versus males: A population-based cohort study.

BACKGROUND: Sex-based disparities in cardiovascular outcomes may be improved with appropriate hypertension management. OBJECTIVE: To compare the evidence-based evaluation and management of females with late-onset hypertension compared to males in the contemporary era. METHODS: Design: Retrospective population-based cohort study. SETTING: Ontario, Canada. PARTICIPANTS: Residents aged ≥66 years with newly diagnosed hypertension between January 1, 2010, and December 31, 2017. EXPOSURE: Sex (female vs. male). OUTCOMES AND MEASURES: We used Poisson and logistic regression to estimate adjusted sex-attributable differences in the performance of guideline-recommended lab investigations. We estimated adjusted differences in time to the prescription of, and type of, first antihypertensive medication prescribed between females and males, using Cox regression. RESULTS: Among 111,410 adults (mean age 73 years, 53% female, median follow-up 6.8 years), females underwent a similar number of guideline-recommended investigations (adjusted incidence rate ratio, 0.997 [95% confidence interval [CI] 0.99-1.002]) compared to males. Females were also as likely to complete all investigations (0.70% females, 0.77% males; adjusted odds ratio, 0.96 [95% CI 0.83-1.11]). Females were slightly less likely to be prescribed medication (adjusted hazard ratio [aHR] 0.98 [95% CI 0.96-0.99]) or, among those prescribed, less likely to be prescribed first-line medication (aHR, 0.995 [95% CI 0.994-0.997]). CONCLUSIONS: Compared to males, females with late-onset hypertension were equally likely to complete initial investigations with comparable prescription rates. These findings suggest that there may be no clinically meaningful sex-based differences in the initial management of late-onset hypertension to explain sex-based disparities in cardiovascular outcomes.

Associations of CD4 Cell Count Measures With Infection-Related and Infection-Unrelated Cancer Risk Among People With HIV.

BACKGROUND: People with HIV are at higher risk of infection-related cancers than the general population, which could be due, in part, to immune dysfunction. Our objective was to examine associations between 4 CD4 count measures as indicators of immune function and infection-related and infection-unrelated cancer risk. SETTING: We conducted a cohort study of adults with HIV who were diagnosed with cancer in Ontario, Canada. Incident cancers were identified from January 1, 1997 to December 31, 2020. METHODS: We estimated adjusted hazard ratios (aHR) for the associations between CD4 measures (baseline CD4, nadir CD4, time-updated CD4, time-updated CD4:CD8) and cancer incidence rates using competing risk analyses, adjusted for socio-demographic factors, history of hepatitis B or C infection, baseline viral load, smoking, and alcohol use. RESULTS: Among 4771 people with HIV, contributing 59,111 person-years of observation, a total of 549 cancers were observed. Low baseline CD4 (<200 cells/µL) (aHR 2.08 [95% CI: 1.38 to 3.13], nadir (<200 cells/µL) (aHR 2.01 [95% CI: 1.49 to 2.71]), low time-updated CD4 (aHR 3.52 [95% CI: 2.36 to 5.24]) and time-updated CD4:CD8 ratio (<0.4) (aHR 2.02 [95% CI: 1.08 to 3.79]) were associated with an increased rate of infection-related cancer. No associations were observed for infection-unrelated cancers. CONCLUSIONS: Low CD4 counts and indices were associated with increased rates of infection-related cancers among people with HIV, irrespective of the CD4 measure used. Early diagnosis and linkage to care and high antiretroviral therapy uptake may lead to improved immune function and could add to cancer prevention strategies such as screening and vaccine uptake.

A Unique Comprehensive Model to Screen Newborns for Severe Combined Immunodeficiency-An Ontario Single-Centre Experience Spanning 2013-2023.

BACKGROUND: Severe combined immunodeficiency (SCID) is a life-threatening genetic disorder caused by critical defects of the immune system. Almost all cases are lethal if not treated within the first two years of life. Early diagnosis and intervention are thus essential for improving patient outcomes. In 2013, Ontario became the first Canadian province to perform newborn screening (NBS) for SCID by T cell receptor excision circles (TRECs) analysis, a surrogate marker of thymic function and lymphocyte maturation. METHODS: This retrospective study reports on nearly 10 years of NBS for SCID at a quaternary referral centre. RESULTS: From August 2013 to April 2023, our centre's densely populated catchment area flagged 162 newborns with low TRECs levels, including 10 cases with SCID. Follow-up revealed other causes of low TRECs, including non-SCID T cell lymphopenia (secondary/reversible or idiopathic causes, and syndromic conditions) and prematurity. A small number of cases with normal repeat TRECs levels and/or T cell subsets were also flagged. Province-wide data from around this period revealed at least 24 diagnosed cases of SCID or Leaky SCID. CONCLUSIONS: This is the first report of NBS outcomes in a Canadian province describing the causative genetic defects, and the non-SCID causes of a positive NBS for SCID.

Wastewater-based surveillance of SARS-CoV-2: Short-term projection (forecasting), smoothing and outlier identification using Bayesian smoothing.

BACKGROUND: Day-to-day variation in the measurement of SARS-CoV-2 in wastewater can challenge public health interpretation. We assessed a Bayesian smoothing and forecasting method previously used for surveillance and short-term projection of COVID-19 cases, hospitalizations, and deaths. METHODS: SARS-CoV-2 viral measurement from the sewershed in Ottawa, Canada, sampled at the municipal wastewater treatment plant from July 1, 2020, to February 15, 2022, was used to assess and internally validate measurement averaging and prediction. External validation was performed using viral measurement data from influent wastewater samples from 15 wastewater treatment plants and municipalities across Ontario. RESULTS: Plots of SARS-CoV-2 viral measurement over time using Bayesian smoothing visually represented distinct COVID-19 "waves" described by case and hospitalization data in both initial (Ottawa) and external validation in 15 Ontario communities. The time-varying growth rate of viral measurement in wastewater samples approximated the growth rate observed for cases and hospitalization. One-week predicted viral measurement approximated the observed viral measurement throughout the assessment period from December 23, 2020, to August 8, 2022. An uncalibrated model showed underprediction during rapid increases in viral measurement (positive growth) and overprediction during rapid decreases. After recalibration, the model showed a close approximation between observed and predicted estimates. CONCLUSION: Bayesian smoothing of wastewater surveillance data of SARS-CoV-2 allows for accurate estimates of COVID-19 growth rates and one- and two-week forecasting of SARS-CoV-2 in wastewater for 16 municipalities in Ontario, Canada. Further assessment is warranted in other communities representing different sewersheds and environmental conditions.

Recommendations for Recovery of the COVID-19 Pandemic-related Diagnostic, Screening, and Procedure Backlog in Ontario: A Survey of Healthcare Leaders.

PURPOSE: The COVID-19 pandemic has resulted in a significant diagnostic, screening, and procedure backlog in Ontario. Engagement of key stakeholders in healthcare leadership positions is urgently needed to inform a comprehensive provincial recovery strategy. METHODS: A list of 20 policy recommendations addressing the diagnostic, screening and procedure backlog in Ontario were transformed into a national online survey. Policy recommendations were rated on a 7-point Likert scale (strongly agree to strongly disagree) and organized into those retained (≥75% strongly agree to somewhat agree), discarded (≥80% somewhat disagree to strongly disagree), and no consensus reached. Survey participants included a diverse sample of healthcare leaders with the potential to impact policy reform. RESULTS: Of 56 healthcare leaders invited to participate, there were 34 unique responses (61% response rate). Participants were from diverse clinical backgrounds, including surgical subspecialties, medicine, nursing, and healthcare administration and held institutional or provincial leadership positions. A total of 11 of 20 policy recommendations reached the threshold for consensus agreement with the remaining 9 having no consensus reached. CONCLUSION: Consensus agreement was reached among Canadian healthcare leaders on 11 policy recommendations to address the diagnostic, screening, and procedure backlog in Ontario. Recommendations included strategies to address patient information needs on expected wait times, expand health and human resource capacity, and streamline efficiencies to increase operating room output. No consensus was reached on the optimal funding strategy within the public system in Ontario or the appropriateness of implementing private funding models.

Patterns of inpatient acute care and emergency department utilization within one year post-initial amputation among individuals with dysvascular major lower extremity amputation in Ontario, Canada: A population-based retrospective cohort study.

INTRODUCTION: Lower extremity amputation (LEA) is a life altering procedure, with significant negative impacts to patients, care partners, and the overall health system. There are gaps in knowledge with respect to patterns of healthcare utilization following LEA due to dysvascular etiology. OBJECTIVE: To examine inpatient acute and emergency department (ED) healthcare utilization among an incident cohort of individuals with major dysvascular LEA 1 year post-initial amputation; and to identify factors associated with acute care readmissions and ED visits. DESIGN: Retrospective cohort study using population-level administrative data. SETTING: Ontario, Canada. POPULATION: Adults individuals (18 years or older) with a major dysvascular LEA between April 1, 2004 and March 31, 2018. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Acute care hospitalizations and ED visits within one year post-initial discharge. RESULTS: A total of 10,905 individuals with major dysvascular LEA were identified (67.7% male). There were 14,363 acute hospitalizations and 19,660 ED visits within one year post-discharge from initial amputation acute stay. The highest common risk factors across all the models included age of 65 years or older (versus less than 65 years), high comorbidity (versus low), and low and moderate continuity of care (versus high). Sex differences were identified for risk factors for hospitalizations, with differences in the types of comorbidities increasing risk and geographical setting. CONCLUSION: Persons with LEA were generally more at risk for acute hospitalizations and ED visits if higher comorbidity and lower continuity of care. Clinical care efforts might focus on improving transitions from the acute setting such as coordinated and integrated care for sub-populations with LEA who are more at risk.

Secondary Stroke Prevention in People With Schizophrenia.

BACKGROUND: People with schizophrenia are less likely than those without to be treated for cardiovascular disease. We aimed to evaluate the association between schizophrenia and secondary preventive care after ischemic stroke. METHODS AND RESULTS: In this retrospective cohort study, we used linked population-based administrative data to identify adults who survived 1 year after ischemic stroke hospitalization in Ontario, Canada between 2004 and 2017. Outcomes were screening, treatment, and control of risk factors, and receipt of outpatient physician services. We used modified Poisson regression to model the relative risk of each outcome among people with and without schizophrenia, adjusting for age and other factors. Among 81 163 people with ischemic stroke, 844 (1.04%) had schizophrenia. Schizophrenia was associated with lower rates of screening for hyperlipidemia (60.5% versus 66.0%, adjusted relative risk [aRR] 0.88 [95% CI, 0.84-0.93]) and diabetes (69.4% versus 73.9%, aRR 0.93 [95% CI, 0.89-0.97]), prescription of antihypertensive medications (91.2% versus 94.7%, aRR 0.96 [95% CI, 0.93-0.99]), achievement of target lipid levels (low-density lipoprotein <2 mmol/L) (30.6% versus 34.6%, aRR 0.86 [95% CI, 0.78-0.96]), and outpatient specialist visits (55.3% versus 67.8%, aRR 0.78 [95% CI, 0.74-0.83]) or primary care physician visits (94.5% versus 98.5%; aRR 0.96 [95% CI, 0.95-0.98]) within 1 year. There were no differences in prescription of antilipemic, antiglycemic, or anticoagulant medications, or in achievement of target hemoglobin A1c ≤7%. CONCLUSIONS: People with stroke and schizophrenia are less likely than those without to receive secondary preventive care. This may inform interventions to improve poststroke care and outcomes in those with schizophrenia.

Effectiveness of Influenza Vaccination During Pregnancy Against Laboratory-Confirmed Seasonal Influenza Among Infants Under 6 Months of Age in Ontario, Canada.

BACKGROUND: Randomized trials conducted in low- and middle-income settings demonstrated efficacy of influenza vaccination during pregnancy against influenza infection among infants <6 months of age. However, vaccine effectiveness (VE) estimates from settings with different population characteristics and influenza seasonality remain limited. METHODS: We conducted a test-negative study in Ontario, Canada. All influenza virus tests among infants <6 months from 2010 to 2019 were identified and linked with health databases to ascertain information on maternal-infant dyads. VE was estimated from the odds ratio for influenza vaccination during pregnancy among cases versus controls, computed using logistic regression with adjustment for potential confounders. RESULTS: Among 23 806 infants tested for influenza, 1783 (7.5%) were positive and 1708 (7.2%) were born to mothers vaccinated against influenza during pregnancy. VE against laboratory-confirmed infant influenza infection was 64% (95% confidence interval [CI], 50%-74%). VE was similar by trimester of vaccination (first/second, 66% [95% CI, 40%-80%]; third, 63% [95% CI, 46%-74%]), infant age at testing (0 to <2 months, 63% [95% CI, 46%-75%]; 2 to <6 months, 64% [95% CI, 36%-79%]), and gestational age at birth (≥37 weeks, 64% [95% CI, 50%-75%]; < 37 weeks, 61% [95% CI, 4%-86%]). VE against influenza hospitalization was 67% (95% CI, 50%-78%). CONCLUSIONS: Influenza vaccination during pregnancy offers effective protection to infants <6 months, for whom vaccines are not currently available.

Development of a "big data" groundwater microbial contamination index and spatial comparisons with enteric infection rates in southern Ontario.

Big data have become increasingly important for policymakers and scientists but have yet to be employed for the development of spatially specific groundwater contamination indices or protecting human and environmental health. The current study sought to develop a series of indices via analyses of three variables: Non-E. coli coliform (NEC) concentration, E. coli concentration, and the calculated NEC:E. coli concentration ratio. A large microbial water quality dataset comprising 1,104,094 samples collected from 292,638 Ontarian wells between 2010 and 2021 was used. Getis-Ord Gi* (Gi*), Local Moran's I (LMI), and space-time scanning were employed for index development based on identified cluster recurrence. Gi* and LMI identify hot and cold spots, i.e., spatially proximal subregions with similarly high or low contamination magnitudes. Indices were statistically compared with mapped well density and age-adjusted enteric infection rates (i.e., campylobacteriosis, cryptosporidiosis, giardiasis, verotoxigenic E. coli (VTEC) enteritis) at a subregional (N = 298) resolution for evaluation and final index selection. Findings suggest that index development via Gi* represented the most efficacious approach. Developed Gi* indices exhibited no correlation with well density, implying that indices are not biased by rural population density. Gi* indices exhibited positive correlations with mapped infection rates, and were particularly associated with higher bacterial (Campylobacter, VTEC) infection rates among younger sub-populations (p < 0.05). Conversely, no association was found between developed indices and giardiasis rates, an infection not typically associated with private groundwater contamination. Findings suggest that a notable proportion of bacterial infections are associated with groundwater and that the developed Gi* index represents an appropriate spatiotemporal reflection of long-term groundwater quality. Bacterial infection correlations with the NEC:E. coli ratio index (p < 0.001) were markedly different compared to correlations with the E. coli index, implying that the ratio may supplement E. coli monitoring as a groundwater assessment metric capable of elucidating contamination mechanisms. This study may serve as a methodological blueprint for the development of big data-based groundwater contamination indices across the globe.

Factors associated with homeless experiences amid the COVID-19 pandemic in the Nipissing District, Ontario, Canada.

Canadian homelessness is an ongoing issue, especially in the Nipissing District, Ontario, where agencies work to support those in need. However, these efforts were challenged with the sudden onset of the COVID-19 pandemic. Drawing on the Cycle of Homelessness model, this study examines sociodemographic factors associated with homeless experiences during the pandemic. Using data from the 2021 (n = 207) Nipissing District homeless enumeration survey and employing bivariate and multivariate binary logistic analyses, this study examined sociodemographic factors associated with reasons of homelessness, barriers to housing loss and experiences of chronic and episodic homelessness during the pandemic. The results showed a significant sociodemographic variation in the experiences of the homeless population during the COVID-19 pandemic. Those over the age of 35 versus their younger counterparts were more likely (43.7%) found in emergency shelters. Multivariate findings indicated that females experienced housing/financial loss and interpersonal/family issues, directly causing homelessness, 2.2 and 2.5 times more than males, respectively. Welfare recipients were more likely to experience health-related reasons for housing loss (Odds Ratio (OR): 2.8), chronic homelessness (OR: 3.3), addiction (OR: 2.9), and mental health-related barriers to housing (OR: 4.1). Those aged 25-34, 25-44, and 45+ were 7.9, 4.9, and 5.1 times more likely to face chronic homelessness. Conclusions: Welfare recipients are more at-risk of health-related housing loss, addiction, and mental health barriers to housing, and chronic homelessness. This could be attributed to poor public planning and policies that put people in marginal economic and housing circumstances, especially during the pandemic. Therefore, policy reform is required to address the main barriers in eliminating homelessness.

Life and love under criminalization: The experiences of people living with HIV in Canada.

Based upon qualitative interviews with 54 women and men living with HIV across Ontario, Canada, this paper examines the impact of HIV criminalization on the sexual and romantic relationships of people living with HIV. This research highlights the navigation strategies people living with HIV create and employ to both navigate and protect themselves from the law. Through a thematic and intersectional analysis, this study shows how adoption of these strategies is unequal, with access to navigation strategies varying along lines of gender, race, and sexual orientation. As a result, women and racialized people living with HIV face more difficulties navigating the impact of the law. HIV criminalization in Canada fuels and validates HIV stigma and produces vulnerability both within and outside of the relationships of people living with HIV. This paper seeks to understand HIV criminalization from the perspective of those governed by the law, in hopes of producing knowledge which will contribute to legal reform, inform policy, and support the development of efficacious secondary prevention initiatives.

Epidemiology and clinical relevance of persistent bacteraemia in patients with Gram-negative bloodstream infection: a retrospective cohort study.

OBJECTIVES: The risk factors and outcomes associated with persistent bacteraemia in Gram-negative bloodstream infection (GN-BSI) are not well described. We conducted a follow-on analysis of a retrospective population-wide cohort to characterize persistent bacteraemia in patients with GN-BSI. METHODS: We included all hospitalized patients >18 years old with GN-BSI between April 2017 and December 2021 in Ontario who received follow-up blood culture (FUBC) 2-5 days after the index positive blood culture. Persistent bacteraemia was defined as having a positive FUBC with the same Gram-negative organism as the index blood culture. We identified variables independently associated with persistent bacteraemia in a multivariable logistic regression model. We evaluated whether persistent bacteraemia was associated with increased odds of 30- and 90-day all-cause mortality using multivariable logistic regression models adjusted for potential confounders. RESULTS: In this study, 8807 patients were included; 600 (6.8%) had persistent bacteraemia. Having a permanent catheter, antimicrobial resistance, nosocomial infection, ICU admission, respiratory or skin and soft tissue source of infection, and infection by a non-fermenter or non-Enterobacterales/anaerobic organism were associated with increased odds of having persistent bacteraemia. The 30-day mortality was 17.2% versus 9.6% in those with and without persistent bacteraemia (aOR 1.65, 95% CI 1.29-2.11), while 90-day mortality was 25.5% versus 16.9%, respectively (aOR 1.53, 95% CI 1.24-1.89). Prevalence and odds of developing persistent bacteraemia varied widely depending on causative organism. CONCLUSIONS: Persistent bacteraemia is uncommon in GN-BSI but is associated with poorer outcomes. A validated risk stratification tool may be useful to identify patients with persistent bacteraemia.