Low household income could increase risk of death after cardiac surgery, according to a recent study.

The association between low socioeconomic status and a higher risk of heart disease and death is well-known. However, most studies are conducted in populations without universal health care coverage, where socioeconomic status can determine access to health care. Researchers conducted this study in Sweden, where the entire population has access to free health care.

For the study, researchers looked at patients in Sweden who had cardiac surgery over a 14-year span. All patients had access to the same health care plan and hospital quality under the country's universal health care plan. All cardiac surgeries in Sweden are performed at a small number of centers with similar standards of care and performance.

According to the researchers, the association between low income and death remained the same despite other socioeconomic status variables, comorbidities and cardiovascular risk factors. The study shows that the impact of socioeconomic status on death cannot be explained by disparities in health care alone and ways to better implement secondary prevention measures for low-income patients should be explored.

Limitations of the study include that registry data used did not include information on lifestyle factors such as smoking habits, job strain, diet, level of physical activity and compliance with medication. Also, there was no data on medication or health care during the follow-up period.

The findings are detailed in the Journal of the American College of Cardiology.