Abstract

Despite universal health coverage, heart attack patients who live in poorer Ontario neighbourhoods are dying at a higher rate and experiencing greater barriers to specialist services than wealthier residents. These findings are contained in a recent study from the Institute for Clinical Evaluative Sciences (ICES) and published in the New England Journal of Medicine. The study tracked 51,591 heart attack patients in Ontario from 1992 to 1997. Using administrative data, the study researchers found that for every $10,000 increase in average neighbourhood income there was an associated 10% reduction in the risk of death, after adjustment for comorbidity, hospital factors and patient proximity to the hospital. Those living in poorer neighbourhoods were also undergoing fewer procedures such as angiography, angioplasty and bypass surgery.

There are several factors that might explain the link between socioeconomic status (SES) and outcomes for post-myocardial infarction. Individuals in lower SES strata show a higher prevalence of contributing factors that precede a heart attack (for example, traditional risk factors/life style factors, such as smoking). These could in turn lead to more aggressive heart disease and worse outcomes post-MI. Process factors that occur after a heart attack, such as access to specialized services or patient compliance to prescribed therapy, may also differ across SES groups. Other factors that may be associated with AMI outcome, such as chronic stress, social isolation and depression may also differ across SES and may be important mediators both pre- and post-MI.

The SESAMI project (Socioeconomic Status and Acute Myocardial Infarction), a series of studies currently under way, is trying to untangle the reasons for SES disparities in AMI recovery. A retrospective chart review will provide clinical detail about heart attack severity and in-hospital process of care in relation to AMI mortality across SES. A prospective component will enable researchers to examine the inter-relationships between SES, mortality and quality of life, post-discharge processes of care and psychosocial issues and will also allow for the exploration of associated measurement effects. The pilot phase of the study is under way in five participating hospitals across the greater Toronto area. With additional funding, the ICES team plans to continue SESAMI over the next few years to grasp the more complex and less understood issues surrounding SES and health.

About the Author

Dr. David Alter is a scientist at ICES, staff cardiologist at Sunnybrook and Women's College Health Sciences Centre, and an assistant professor in the Department of Medicine at the University of Toronto.

Karey Iron is a Research Coordinator at ICES.