A Surveillance System to Monitor Excess Mortality of People with Mental Illness in Canada

Abstract

Objective: Outcome measures are rarely available for surveillance and system performance monitoring for mental disorders and addictions. Our study aims to demonstrate the feasibility and face validity of routinely measuring the mortality gap in the Canadian context at the provincial and regional levels using the methods and data available to the Canadian Chronic Disease Surveillance System (CCDSS) of the Public Health Agency of Canada. Methods: We used longitudinal data from the Quebec Integrated Chronic Disease Surveillance System, which also provides aggregated data to the CCDSS. This includes data from the health insurance registry physician claims and the hospital discharge abstract for all mental disorder diagnoses (International Classification of Diseases [ICD]-9 290–319 or ICD-10 F00–F99). Patients were defined as having had received a mental disorder diagnosis at least once during the year. Life expectancy was measured using Chiang's method for abridged life tables, complemented by the Hsieh method for adjustment of the last age interval. Results: We found a lower life expectancy among psychiatric patients of 8 years for men and 5 years for women. For patients with schizophrenia, life expectancy was lowered by 12 years for men and 8 years for women. Cardiovascular disease and cancer were the most common causes of premature death. Findings were consistent across time and regions of the province. Lower estimates of the mortality gap, compared with literature, could be explained by the inclusion of primary care patients and methods. Conclusions: Our study demonstrates the feasibility of using administrative data to measure the impact of current and future mental health plans in Canada provided the techniques can be replicated in other Canadian provinces.