Multimorbidity in Canada: Examining Prevalence and Patterns Using a National Electronic Medical Record Database

Talk Code: 
Kathryn Nicholson
Amanda Terry PhD, Martin Fortin MD MSc CMFC (F), Tyler Williamson PhD, Michael Bauer PhD, Amardeep Thind MD PhD
Author institutions: 
Western University (Ontario, Canada), Universite de Sherbrooke (Quebec, Canada), University of Calgary (Alberta, Canada)


Multimorbidity, the coexistence of multiple chronic diseases, is a significant burden for patients and primary health care (PHC) providers alike. While prominent in older patients, recent studies have found increasing prevalence of multimorbidity in younger patients. Enhanced understanding of the clusters and natural history of multimorbidity, particularly within the Canadian context, is needed. The objectives of this research are three-fold: 1) To determine prevalence and characteristics of adult PHC patients with multimorbidity; 2) To examine patterns of multimorbidity; and 3) To delineate progression of multimorbidity over time.


A retrospective cohort was followed prospectively within clinical data. Data were derived from the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) electronic medical record (EMR) database, which collects longitudinal, de-identified clinical data from PHC practices across Canada. Patients who had > 1 in-office encounter recorded in their EMR and who were > 18 years at first encounter date were included (N=367,743). Chronic disease diagnoses were identified using the International Classification of Diseases, 9th Revision (ICD-9) and a list of 20 chronic disease categories was used to identify patients with multimorbidity. Computational analyses were conducted using a customized JAVA program, while statistical analyses were conducted using Stata 13.1 software.


Overall, 42.6% of adult PHC patients were living with ≥ 2 chronic diseases or multimorbidity. These patients had an average age of 55.5 years (SD: 16.9) and majority were female (59.1%) and living in an urban setting (73.8%). The most frequently occurring combinations of chronic diseases were: 1) anxiety/depression and musculoskeletal problem; 2) hypertension and musculoskeletal problem; 3) hypertension and hyperlipidemia; and 4) hypertension and diabetes. The most prevalent chronic diseases were also explored among patient age groups, and demonstrate changing burden of disease among older patients with multimorbidity. Preliminary survival analyses have shown a decrease in time elapsing between subsequent chronic diseases, from an average of 698.7 days between first and second diagnoses, to an average of 381.2 days between fourth and fifth diagnoses.


This research explores the prevalence and clinical profiles of adult PHC patients with multimorbidity in Canada. This research represents the first national prevalence estimates of multimorbidity in Canada, using a robust EMR database. These findings will contribute the Canadian context to the international multimorbidity literature. This information can also be used strategically to inform more effective health care policy, clinical practice guideline redevelopment and health care delivery.

Submitted by: 
Kathryn Nicholson
Funding acknowledgement: 
Kathryn Nicholson is supported by the Schulich School of Medicine & Dentistry and the Ontario Graduate Scholarship. Dr. Martin Fortin holds an Applied Chair in Health Services and Policy Research on Chronic Diseases in Primary Care. Dr. Amardeep Thind holds a Canada Research Chair in Health Services Research.