Derivation and validation of predictive indices for cardiac readmission after coronary and valvular surgery - A multicenter study.

Objective: To derive and validate models to predict the risk of a cardiac readmission within one year after specific cardiac surgeries using information that is commonly available from hospital electronic medical records. Methods: In this retrospective cohort study, we derived and externally validated clinical models to predict the likelihood of cardiac readmissions within one-year of isolated CABG, AVR, and combined CABG+AVR in Ontario, Canada, using multiple clinical registries and routinely collected administrative databases. For all adult patients who underwent these procedures, multiple Fine and Gray subdistribution hazard models were derived within a competing-risk framework using the cohort from April 2015 to March 2018 and validated in an independent cohort (April 2018 to March 2020). Results: For the model that predicted post-CABG cardiac readmission, the c-statistic was 0.73 in the derivation cohort and 0.70 in the validation cohort at one-year. For the model that predicted post-AVR cardiac readmission, the c-statistic was 0.74 in the derivation and 0.73 in the validation cohort at one-year. For the model that predicted cardiac readmission following CABG+AVR, the c-statistic was 0.70 in the derivation and 0.66 in the validation cohort at one-year. Conclusions: Prediction of one-year cardiac readmission for isolated CABG, AVR, and combined CABG+AVR can be achieved parsimoniously using multidimensional data sources. Model discrimination was better than existing models derived from single and multicenter registries.

Validating a novel deterministic privacy-preserving record linkage between administrative & clinical data: applications in stroke research.

Introduction: Research data combined with administrative data provides a robust resource capable of answering unique research questions. However, in cases where personal health data are encrypted, due to ethics requirements or institutional restrictions, traditional methods of deterministic and probabilistic record linkages are not feasible. Instead, privacy-preserving record linkages must be used to protect patients' personal data during data linkage. Objectives: To determine the feasibility and validity of a deterministic privacy preserving data linkage protocol using homomorphically encrypted data. Methods: Feasibility was measured by the number of records that successfully matched via direct identifiers. Validity was measured by the number of records that matched with multiple indirect identifiers. The threshold for feasibility and validity were both set at 95%. The datasets shared a single, direct identifier (health card number) and multiple indirect identifiers (sex and date of birth). Direct identifiers were encrypted in both datasets and then transferred to a third-party server capable of linking the encrypted identifiers without decrypting individual records. Once linked, the study team used indirect identifiers to verify the accuracy of the linkage in the final dataset. Results: With a combination of manual and automated data transfer in a sample of 8,128 individuals, the privacy-preserving data linkage took 36 days to match to a population sample of over 3.2 million records. 99.9% of the records were successfully matched with direct identifiers, and 99.8% successfully matched with multiple indirect identifiers. We deemed the linkage both feasible and valid. Conclusions: As combining administrative and research data becomes increasingly common, it is imperative to understand options for linking data when direct linkage is not feasible. The current linkage process ensured the privacy and security of patient data and improved data quality. While the initial implementations required significant computational and human resources, increased automation keeps the requirements within feasible bounds.

Derivation and validation of predictive indices for 30-day mortality after coronary and valvular surgery in Ontario, Canada.

BACKGROUND: Coronary artery bypass grafting (CABG) and surgical aortic valve replacement (AVR) are the 2 most common cardiac surgery procedures in North America. We derived and externally validated clinical models to estimate the likelihood of death within 30 days of CABG, AVR or combined CABG + AVR. METHODS: We obtained data from the CorHealth Ontario Cardiac Registry and several linked population health administrative databases from Ontario, Canada. We derived multiple logistic regression models from all adult patients who underwent CABG, AVR or combined CABG + AVR from April 2017 to March 2019, and validated them in 2 temporally distinct cohorts (April 2015 to March 2017 and April 2019 to March 2020). RESULTS: The derivation cohorts included 13 435 patients who underwent CABG (30-d mortality 1.73%), 1970 patients who underwent AVR (30-d mortality 1.68%) and 1510 patients who underwent combined CABG + AVR (30-d mortality 3.05%). The final models for predicting 30-day mortality included 15 variables for patients undergoing CABG, 5 variables for patients undergoing AVR and 5 variables for patients undergoing combined CABG + AVR. Model discrimination was excellent for the CABG (c-statistic 0.888, optimism-corrected 0.866) AVR (c-statistic 0.850, optimism-corrected 0.762) and CABG + AVR (c-statistic 0.844, optimism-corrected 0.776) models, with similar results in the validation cohorts. INTERPRETATION: Our models, leveraging readily available, multidimensional data sources, computed accurate risk-adjusted 30-day mortality rates for CABG, AVR and combined CABG + AVR, with discrimination comparable to more complex American and European models. The ability to accurately predict perioperative mortality rates for these procedures will be valuable for quality improvement initiatives across institutions.

The Canadian Alliance for Healthy Hearts and Minds: How Well Does It Reflect the Canadian Population?

BACKGROUND: The intent of the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort is to understand the early determinants of subclinical cardiac and vascular disease and progression in adults selected from existing cohorts-the Canadian Partnership for Tomorrow's Health, the Prospective Urban and Rural Evaluation (PURE) cohort, and the Montreal Heart Institute Biobank. We evaluated how well the CAHHM-Health Services Research (CAHHM-HSR) subcohort reflects the Canadian population. METHODS: A cross-sectional design was used among a prospective cohort of community-dwelling adults aged 35-69 years who met the CAHHM inclusion criteria, and a cohort of adults aged 35-69 years who responded to the 2015 Canadian Community Health Survey-Rapid Response module. The INTERHEART risk score was calculated at the individual level with means and proportions reported at the overall and provincial level. RESULTS: There are modest differences between CAHHM-HSR study participants and the 2015 Canadian Community Health Survey-Rapid Response respondents in age (56.3 vs 51.7 mean years), proportion of men (44.9% vs 49.3%), and mean INTERHEART risk score (9.7 vs 10.1). Larger differences were observed in postsecondary education (86.8% vs 70.2%), Chinese ethnicity (11.0% vs 3.3%), obesity (23.2% vs 29.3%), current smoker status (6.1% vs 18.4%), and having no cardiac testing (30.4% vs 55.9%). CONCLUSIONS: CAHHM-HSR participants are older, of higher socioeconomic status, and have a similar mean INTERHEART risk score, compared with participants in the Canadian Community Health Survey. Differing sampling strategies and missing data may explain some differences between the CAHHM-HSR cohort and Canadian community-dwelling adults and should be considered when using the CAHHM-HSR for scientific research.

CONTEXTE: L'étude Alliance canadienne cœurs et cerveaux sains (CAHHM) vise à mieux comprendre les facteurs déterminants précoces et la progression de l'atteinte cardiovasculaire subclinique chez des adultes sélectionnés au sein de cohortes existantes ­ soit celles de l'étude menée par le Partenariat canadien pour la santé de demain, de l'étude PURE (Prospective Urban and Rural Evaluation) et de la biobanque de l'Institut de cardiologie de Montréal. Nous avons évalué la mesure dans laquelle la sous-cohorte du volet de recherche sur l'utilisation des services de santé de la CAHHM (CAHHM-HSR) représente la population canadienne. MÉTHODOLOGIE: Nous avons adopté une approche transversale pour étudier une cohorte prospective d'adultes vivant dans la communauté âgés de 35 à 69 ans et répondant aux critères d'inclusion de l'étude CAHHM, ainsi qu'une cohorte d'adultes âgés de 35 à 69 ans ayant participé au volet de réponse rapide de l'Enquête sur la santé dans les collectivités canadiennes (ESCC) de 2015. Le score de risque INTERHEART individuel des participants a été calculé à partir des moyennes et des proportions rapportées à l'échelle globale et à l'échelle provinciale. RÉSULTATS: Les différences entre les participants du volet CAHHM-HSR et ceux du volet de réponse rapide de l'ESCC de 2015 étaient minimes quant à l'âge (56,3 ans vs 51,7 ans en moyenne), à la proportion d'hommes (44,9 % vs 49,3 %) et au score de risque INTERHEART moyen (9,7 vs 10,1). On a toutefois noté des différences plus importantes en ce qui concerne les caractéristiques suivantes : éducation postsecondaire (86,8 % vs 70,2 %), origine ethnique chinoise (11,0 % vs 3,3 %), obésité (23,2 % vs 29,3 %), tabagisme actuel (6,1 % vs 18,4 %) et absence d'antécédents d'examen cardiaque (30,4 % vs 55,9 %). CONCLUSIONS: Les participants du volet CAHHM-HSR sont plus âgés et ont un statut socioéconomique plus élevé que ceux du volet de réponse rapide de l'ESCC, mais ont un score de risque INTERHEART moyen comparable. Les différences quant aux stratégies d'échantillonnage et des données manquantes pourraient expliquer certains des écarts observés entre la cohorte CAHHM-HSR et celle des adultes canadiens vivant dans la communauté; il conviendrait d'en tenir compte lorsqu'on utilise les données du volet CAHHM-HSR à des fins de recherche scientifique.

Comparison of Cardiovascular Risk Factors and Outcomes Among Practicing Physicians vs the General Population in Ontario, Canada.

Importance: Although cardiovascular disease is the leading cause of death in most developed countries, little is known about current physicians' cardiovascular health and outcomes. Objective: To compare cardiac risk factor burden, health services use, and major cardiovascular event incidence between physicians and the general population. Design, Setting, and Participants: This cohort study used data from practicing physicians and nonphysicians without cardiovascular disease aged 40 to 75 years in Ontario, Canada. Cohorts were assembled beginning January 1, 2008, and were followed up to December 31, 2015. Data analysis was performed between November 2017 and September 2019. Exposure: Being a practicing physician. Main Outcomes and Measures: The primary outcome was 8-year incidence of a major cardiovascular event (ie, cardiovascular death or hospitalization for myocardial infarction, stroke, heart failure, or coronary revascularization). Secondary outcomes included health services used, such as physician assessments and guideline-recommended tests. Results: The cohort comprised 17 071 physicians (mean [SD] age, 53.3 [8.8] years; 11 963 [70.1%] men) and 5 306 038 nonphysicians (mean [SD] age, 53.7 [9.5] years; 2 556 044 [48.2%] men). Physicians had significantly lower baseline rates of hypertension (16.9% vs 29.6%), diabetes (5.0% vs 11.3%), and smoking (13.1% vs 21.6%), while having better cholesterol profiles (total cholesterol levels >240 mg/dL, 13.3% vs 16.5%; low-density lipoprotein cholesterol >130 mg/dL, 33.2% vs 36.8%); age- and sex-adjusted differences were even larger. Physicians also had lower rates of periodic health examinations (58.9% [95% CI, 57.5%-60.4%] vs 67.9% [95% CI, 67.8%-67.9%]), hyperlipidemia screening (76.3% [95% CI, 74.7%-78.0%] vs 83.8% [95% CI, 83.7%-83.9%]), and diabetes screening (79.0% [95% CI, 77.3%-80.8%] vs 85.3% [95% CI, 85.2%-85.4%]), but higher rates of cardiologist consultations (25.2% [95% CI, 24.2%-26.3%] vs 19.5% [95% CI, 19.4%-19.5%]). The 8-year age- and sex-standardized primary outcome incidence was 4.4 major cardiovascular events per 1000 person-years for physicians and 7.1 major cardiovascular events per 1000 person-years for the general population. After adjusting for age, sex, socioeconomic status, and cardiac risks and comorbidities, physicians had a 22% lower hazard (hazard ratio, 0.78; 95% CI, 0.72-0.85) of experiencing the primary outcome compared with the general population. Conclusions and Relevance: Practicing physicians in Ontario had fewer cardiovascular risk factors, underwent less preventive testing, and were less likely to experience major adverse cardiovascular outcomes than the general population.

Canadian Alliance for Healthy Hearts and Minds: First Nations Cohort Study Rationale and Design.

BACKGROUND: This is the first national indigenous cohort study in which a common, in-depth protocol with a common set of objectives has been adopted by several indigenous communities across Canada. OBJECTIVES: The overarching objective of the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort is to investigate how the community-level environment is associated with individual health behaviors and the presence and progression of chronic disease risk factors and chronic diseases such as cardiovascular disease (CVD) and cancer. METHODS: CAHHM aims to recruit approximately 2,000 First Nations indigenous individuals from up to nine communities across Canada and have participants complete questionnaires, blood collection, physical measurements, cognitive assessments, and magnetic resonance imaging (MRI). RESULTS: Through individual- and community-level data collection, we will develop an understanding of the specific role of the socioenvironmental, biological, and contextual factors have on the development of chronic disease risk factors and chronic diseases. CONCLUSIONS: Information collected in the indigenous cohort will be used to assist communities to develop local management strategies for chronic disease, and can be used collectively to understand the contextual, environmental, socioeconomic, and biological determinants of differences in health status in harmony with First Nations beliefs and reality.

Rationale, design, and methods for Canadian alliance for healthy hearts and minds cohort study (CAHHM) - a Pan Canadian cohort study.

BACKGROUND: The Canadian Alliance for Healthy Hearts and Minds (CAHHM) is a pan-Canadian, prospective, multi-ethnic cohort study being conducted in Canada. The overarching objective of the CAHHM is to understand the association of socio-environmental and contextual factors (such as societal structure, activity, nutrition, social and tobacco environments, and access to health services) with cardiovascular risk factors, subclinical vascular disease, and cardiovascular and other chronic disease outcomes. METHODS/DESIGN: Participants between 35 and 69 years of age are being recruited from existing cohorts and a new First Nations Cohort to undergo a detailed assessment of health behaviours (including diet and physical activity), cognitive function, assessment of their local home and workplace environments, and their health services access and utilization. Physical measures including weight, height, waist/hip circumference, body fat percentage, and blood pressure are collected. In addition, eligible participants undergo magnetic resonance imaging (MRI) of the brain, heart, carotid artery and abdomen to detect early subclinical vascular disease and ectopic fat deposition. DISCUSSION: CAHHM is a prospective cohort study designed to investigate the impact of community level factors, individual health behaviours, and access to health services, on cognitive function, subclinical vascular disease, fat distribution, and the development of chronic diseases among adults living in Canada.

Prevalence of zoonotic bacteria in wild and farmed aquatic species and seafood: a scoping study, systematic review, and meta-analysis of published research.

Increased reliance on seafood has brought to light concerns regarding food safety, but the information to inform risk assessment or surveillance needs is lacking. A scoping study (ScS) was conducted to characterize published research investigating selected zoonotic bacteria and public health topics in various wild and farmed aquatic species and seafood. This was followed by a systematic review (SR) on selected bacteria (Aeromonas spp., generic Escherichia coli, Salmonella spp., and Vibrio spp.) and aquatic species (clams, mussels, oysters, salmon, and shrimp [including prawn]); a meta-analysis (MA) was conducted only at the retail level due to considerable variability among various pathogen/seafood combinations. The ScS revealed the most frequently investigated themes were farm-level prevalence and intervention research for Vibrio spp. and Aeromonas spp. Antimicrobial use (AMU) and the association between AMU and antimicrobial resistance were rarely investigated. The SR indicated a consistent lack of reporting regarding study methodology and results, precluding the use of many studies in and full benefits of MA. MA of Aeromonas, E. coli, and Salmonella prevalence in retail salmon resulted in pooled estimates of 13% (6-27%), 2% (0.1-11%), and 1% (0-5%), respectively. When MA of pathogen/seafood combination resulted in statistically significant heterogeneity (p<0.1), median/range were reported at the region level. The results from our ScS, SR, and MA could be used for better design of future bacteriological surveys of seafood and as inputs for risk assessments or surveillance initiatives in this field.