Background: Health insurance plays an important role in access to medical care and is the focus of extensive policy efforts. We examined the association of health insurance with cardiovascular disease (CVD) incidence.
Methods and Results: The Multi-Ethnic Study of Atherosclerosis, sponsored by the National Heart, Lung and Blood Institute of the NIH, followed a US cohort, aged 45-84 without clinical CVD at baseline, for a median of 12.2 years; 788 events occurred among 6,674 individuals. Data were stratified by baseline health insurance status. Kaplan-Meier survival and Cox regression analyses were used to assess the association between health insurance and incident CVD (myocardial infarction, resuscitated cardiac arrest, stroke, CVD death, and angina), adjusting for biomedical CVD risk (traditional risk factors, including age and race/ethnicity, and markers of subclinical atherosclerosis) and socioeconomic status (SES). The majority of individuals had private insurance (51%). Uninsured individuals (9%) were more likely to have untreated hypertension and diabetes, less likely to be on lipid-lowering therapy, and more likely to receive care in an Emergency Department (p < 0.0001). Income, 10-year CVD risk, and 10-year event-free survival varied across insurance groups (Table). After adjustment for biomedical CVD risk, individuals with health insurance had a lower risk of incident CVD compared to the uninsured (HR 0.72, p=0.03). However, with additional adjustment for SES (income, education, and employment), insurance was no longer associated with incident CVD (HR 0.78, p=0.12). Among the insurance groups, those with private insurance had a lower risk of incident CVD after adjustment for both biomedical CVD risk and SES (HR 0.70, p=0.03). Medicare and Medicaid coverage were not associated with incident CVD. The military/VA group had a lower risk of incident CVD with adjustment for biomedical CVD risk (HR 0.57, p=0.02) that was no longer significant after adjustment for SES (HR 0.66, p=0.09).
Conclusions: The association of health insurance with CVD incidence varied by insurance group, and private insurance was associated with a lower risk of incident CVD. Further exploration of the features of health insurance coverage that impact CVD incidence may facilitate improvements in the primary prevention of CVD.