Insurance status, not race, is associated with mortality after an acute cardiovascular event in Maryland

It is unclear how lack of health insurance or otherwise being underinsured contributes to observed racial disparities in health outcomes related to cardiovascular disease.

To determine the relative risk of death associated with insurance and race after hospital admission for an acute cardiovascular event.

Prospective cohort study in three hospitals in Maryland representing different demographics between 1993 and 2007.

Patients with an incident admission who were either white or black, and had either private insurance, state-based insurance or were uninsured. 4,908 patients were diagnosed with acute myocardial infarction, 6,759 with coronary atherosclerosis, and 1,293 with stroke.

Demographic and clinical patient-level data were collected from an administrative billing database and neighborhood household income was collected from the 2000 US Census. The outcome of all-cause mortality was collected from the Social Security Death Master File.

In an analysis adjusted for race, disease severity, location, neighborhood household income among other confounders, being underinsured was associated with an increased risk of death after myocardial infarction (relative hazard, 1.31 [95 % CI: 1.09, 1.59]), coronary atherosclerosis (relative hazard, 1.50 [95 % CI: 1.26, 1.80]) or stroke (relative hazard, 1.25 [95 % CI: 0.91, 1.72]). Black race was not associated with an increased risk of death after myocardial infarction (relative hazard, 1.03 [95 % CI: 0.85, 1.24]), or after stroke (relative hazard, 1.18 [95 % CI: 0.86, 1.61]) and was associated with a decreased risk of death after coronary atherosclerosis (relative hazard, 0.82 [95 % CI: 0.69, 0.98]).

Race was not associated with an increased risk of death, before or after adjustment. Being underinsured was strongly associated with death among those admitted with myocardial infarction, or a coronary atherosclerosis event. Our results support growing evidence implicating insurance status and socioeconomic factors as important drivers of health disparities, and potentially racial disparities.