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

BACKGROUND: It is unclear how lack of health insurance or otherwise being underinsured contributes to observed racial disparities in health outcomes related to cardiovascular disease. OBJECTIVE: To determine the relative risk of death associated with insurance and race after hospital admission for an acute cardiovascular event. DESIGN: Prospective cohort study in three hospitals in Maryland representing different demographics between 1993 and 2007. PATIENTS: 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. MAIN MEASURES: 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. KEY RESULTS: 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]). CONCLUSIONS: 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.