Homeless people are three times more likely to die after a heart attack compared to other patients probably as a result of chronic stress, higher rates of smoking, and poverty, according to new research.

The study presented at the 2020 Canadian Cardiovascular Congress (CCC),  examined all patients admitted with a severe form of heart attack to an inner-city hospital in Toronto during a 10-year period. Demographics, clinical characteristics and outcomes were compared between homeless and non-homeless patients.

A total of 2,856 patients presented with ST-segment elevation myocardial infarction (STEMI) to St. Michael’s Hospital, Toronto, in 2008 to 2017. Of those, 75 patients (2.6%) were identified as homeless.

The rate of in-hospital mortality was significantly higher in the homeless compared to the non-homeless patients (18.7% versus 5.6%, p<0.0001). Homeless heart attack patients were significantly younger than non-homeless patients and more likely to be men. The average age of the homeless group was 58.2 years compared to 62.7 years for the non-homeless group. Some 95.9% of the homeless group were men compared to 76.5% of the non-homeless patients.

Higher rate of current smoking in the homeless group

Regarding risk factors for a heart attack, there was a significantly higher rate of current smoking in the homeless (83.6%) compared to non-homeless (50.4%) patients. Rates of high blood pressure, high serum cholesterol, and diabetes were similar between the two groups.

“Our study shows a dramatically higher rate of mortality after heart attacks in people experiencing homelessness compared to non-homeless patients,” said study author Dr. Samantha Liauw of the University of Toronto. “More research is needed to discover the reasons for this disparity in outcomes so that the chances of survival can be improved in this vulnerable population.”

Looking at medical history, 29% of homeless patients had previous or current psychiatric conditions compared to less than 2% of the non-homeless group. Alcohol abuse was reported in 24% and 1%  of the homeless and non-homeless group, respectively. Cocaine use was recorded in 15% and less than 1% of the homeless group and non-homeless groups, respectively. Histories of coronary artery disease and heart failure were similar between groups, but significantly more homeless patients had peripheral arterial disease (11%) compared to the non-homeless patients (less than 3%).

Need new methods to study this disadvantaged part of society

Heart attack severity was similar between the two groups, but more homeless patients presented with cardiogenic shock or cardiac arrest (15%) than the non-homeless group (4%). Both groups received high rates of medications, invasive testing, and stenting, but the rate of stenting was lower in the homeless cohort (80.0% versus 89.7%; p=0.0071). Rates of cholesterol-lowering medications (statins) outside hospital were not significantly different.

The study had insufficient numbers of patients to analyse which characteristics may be responsible for the lower survival in homeless patients. But Dr Liauw said: “The elevated risk at a younger age could be related to chronic stress from being homeless, higher rates of smoking, poverty, and unreliable access to healthy food. Lack of trust in the medical system, poor access to healthcare for chronic conditions, and slower receipt of emergency therapies may also have contributed.”

Life-saving treatment for heart attacks must be delivered quickly to have the most benefit. Dr Liauw added: “In our study, the time from symptom onset to undergoing a procedure to open blocked arteries was similar between the homeless and non-homeless groups. However, I suspect that the symptom start time recorded for homeless patients may be inaccurate – for example because they were unconscious when the ambulance was called – and that there was a longer gap before therapy. This illustrates that we need new methods to study this disadvantaged part of society.”