Cardiovascular risk factors among homeless people are under-treated in Canada

May 18 2005

Cardiovascular risk factors among homeless people are under-treated in Canada, despite universal health coverage there, researchers report in Circulation - Journal of the American Heart Association.

The study, the first comprehensive assessment of cardiovascular risk factors in a representative sample of homeless adults, also found that cardiovascular risks among the homeless may be underestimated due to commonly used risk assessment tools that do not account for cocaine use and the level of smoking exposure.

“We set out to examine cardiovascular risk factors in homeless adults in Toronto and to identify opportunities for improved risk factor modification,” said the study’s senior author, Stephen W. Hwang, M.D., M.P.H.

“This information will be an essential first step towards improving cardiovascular health in this extremely disadvantaged population,” said Hwang, a research scientist at the Centre for Research on Inner City Health at St. Michael’s Hospital and assistant professor of medicine at the University of Toronto.

Homelessness is widespread in North America, with an estimated 800,000 Americans being homeless in any given week; and in 2002, 30,000 people in Toronto, Canada, alone used a homeless shelter, according to government records. Previous studies in Boston and Toronto found that middle-aged homeless men were 40 percent to 50 percent more likely to die of heart disease than men in the general population. Researchers surmise that the reasons are a high prevalence of cardiovascular risk factors and obstacles to appropriate risk factor management.

The researchers studied a random sample of 202 people staying at homeless shelters for single adults in Toronto during one year. Participants averaged 42 years of age and 89 percent were men. The researchers interviewed the participants, conducted physical evaluations and took blood samples to assess their cardiovascular risk.

Overall, they found a much higher prevalence of smoking, but not diabetes, hypertension or obesity compared to the general population of Canada. However, they also noted inadequate treatment for hypertension and high blood cholesterol,and poor control of diabetes. For example, 35 percent of the homeless adults had hypertension, but only 17 percent were taking medication.

“Fifteen percent of the homeless subjects in the study already had cardiovascular disease, which is surprisingly high,” Hwang said. Yet only a fraction of those with cardiovascular disease were taking cholesterol-lowering medication (20 percent) or aspirin (30 percent).

Among the homeless men, the estimated average risk of suffering a heart attack or dying of coronary disease in the next 10 years was 5 percent, which surprisingly is about the same as men in the general population of Framingham, Mass., Hwang said. The Framingham population is used to estimate a person’s risk for heart attack or coronary death within 10 years based on risk factors such as age, male gender and high blood pressure.

“But the commonly used Framingham risk assessment tool doesn’t account for factors that are common among homeless people, such as the level of smoking exposure and cocaine use,” Hwang said. “For example, the traditional coronary risk assessment tools don’t distinguish between smoking and heavy smoking.”

Hwang said that 78 percent of the participants in the study smoked – significantly higher than the general Canadian population. And 29 percent of those in the study reported using cocaine in the last year, which is associated with an increased likelihood of heart disease.

As a result, these tools probably underestimate the coronary risk of homeless people, he said.

“It’s interesting to note that this study was done in Canada, where everyone is covered by a system of universal health insurance,” Hwang said. “Our study shows that while universal health insurance is of vital importance, it is not sufficient to ensure that homeless and other disadvantaged populations get good cardiovascular risk factor modification.”

The authors said that their findings may not be similar to homeless people in other cities. They said future studies should explore how to provide better primary health care and cardiovascular risk modification to homeless people, and whether coronary risk assessment tools should be refined to include additional factors such as cocaine use or poverty itself.

In an accompanying editorial Jessie M. McCary, M.D. and James J. O’Connell, M.D., of the Boston Health Care for the Homeless Program, said the findings expose a resounding need for community-wide interventions to improve the cardiovascular health of homeless people.

“Primary and secondary prevention of coronary artery disease requires lifestyle changes and often medication; however, these are not effective treatment strategies in patients without stable, permanent and supportive living environments,” they wrote. “The close link between housing and health must be recognized, and housing should be considered a critical medical priority.”