Sudden cardiac arrest was higher among people living in poorer neighbourhoods in several US and Canadian cities, and the disparity was particularly evident among people under age 65, found a study in CMAJ.
Sudden cardiac arrest accounts for up to 63% of deaths annually from cardiac diseases in the United States. Socioeconomic status is a predictor of many health-related conditions, including death and heart disease. This study examined a potential link between socioeconomic status and sudden cardiac arrest in more than one community.
A team of researchers in the US and Canada looked at data on 9235 sudden cardiac arrests in seven cities: four in the US: Dallas, Texas; Pittsburgh, Pennsylvania; Portland, Oregon; Seattle-King County, Washington; and three in Canada: Ottawa and Toronto, Ontario; and Vancouver, British Columbia.
The researchers looked at people who had cardiac arrests at home, a nursing home or assisted-living facility. They used census tract data on household incomes for the location of cardiac arrests to determine socioeconomic status.
"The incidence of sudden cardiac arrest was significantly higher in the neighbourhoods of lowest versus highest socioeconomic status in six of the seven metropolitan areas studied," writes Dr. Sumeet Chugh, Cedars-Sinai Medical Center, with coauthors.
Median household income was $50 000 to $63 000 US dollars, with income in the lowest socioeconomic group ranging from $30 000 to $41 000 and in the highest socioeconomic group from $72 000 to $97 000. In Pittsburgh, incomes were significantly lower ($21 000 and $54 000 respectively.)
"At all seven sites, disparities in the incidence of sudden cardiac arrest across socioeconomic quartiles were greatest among people less than 65 years old. Compared with the incidence in the highest quartile, the incidence in the lowest quartile was two- to fourfold greater in the US sites, and up to threefold greater in the Canadian sites," they write. "As with all ages combined, disparities across socioeconomic quartiles among people younger than 65 were significant at all sites except Ottawa." Compared with the disparities among younger people, the disparities among people 65 and older were less pronounced in in the US cities and Toronto.
The trend for higher cardiac arrests increased as median income dropped and was particularly noticeable among people under 65 years of age and stronger in the US cities than in the Canadian cities. The authors state that the exact reasons for US-Canadian differences need further investigation, but data from other studies indicate that one possible explanation is Canadians' access to universal health care; which may mean they have had preventive care for cardiac issues, compared with Americans who may not seek care because of cost, particularly those younger than 65 and not yet eligible for Medicare.
"Our results showing a younger mean age of sudden cardiac arrest in the United States may be consistent with more poorly controlled cardiovascular disease," state the authors.
They conclude that population-level interventions for people in low income neighbourhoods and better access to preventive health care may help to address these disparities.
In a related commentary, Dr. Heikki Huikuri, Institute of Clinical Medicine, University of Oulu, Finland, writes "this study should inform the decisions of politicians and managers of health care systems as they institute health care reforms, recognizing that sudden cardiac arrest is the single most common cause of death in western societies."
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