Medicaid-insured and uninsured patients with acute myocardial infarction (MI) had a significantly lower chance of receiving percutaneous coronary intervention (PCI) treatment and a higher likelihood of death and rehospitalization compared with privately insured patients, according to a study published in the Journal of the American Heart Association.

The Affordable Care Act reduced the percentage of uninsured Americans from 20.3% in 2012 to 12.6% in 2015. Although having insurance coverage increases access to medical care, insurance coverage is not all equal. Studies have indicated that Medicaid-insured patients and those who are uninsured receive different care after an acute MI than those with private insurance. However, these studies did not control for hospital fixed effects, and they looked either at a limited sample of hospitals or a limited set of outcomes.

Matthew J. Niedzwiecki, PhD, from the Department of Emergency Medicine and the Philip R. Lee Institute for Health Policy Studies at the University of California at San Francisco, and colleagues conducted a multivariate regression analysis of data for all nonelderly adult patients with an acute MI in California from January 1, 2001, to December 31, 2014, using patient-level data. The investigators used hospital-level information to control for differences between hospitals.

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The final sample contained a total of 198,420 patients; 65.5% of them were privately insured, 18.6% had Medicaid coverage, and 15.9% were uninsured. Medicaid-insured and uninsured patients were more likely to have access to a catheterization laboratory (4.50 and 3.75 percentage points, respectively) than privately insured patients. However, when controlling for access to PCI facilities, Medicaid-insured and uninsured patients were 4.24 and 0.85 percentage points less likely to receive PCI treatment than privately insured patients. The probability of dying within 30, 90, and 365 days for Medicaid-insured patients was 1.46, 2.36, and 4.05 percentage points higher, respectively, than for privately insured patients. The probability of being readmitted to the hospital for Medicaid-insured patients was 33.4% higher than for privately insured patients. No significant differences were found between uninsured and privately insured patients for mortality or readmission.

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Although Medicaid patients with segment-elevation myocardial infarction (STEMI) had a higher likelihood of being admitted to a hospital with PCI capacity, they were less likely to receive PCI treatment when compared with privately insured patients within the same hospital (−2.07 percentage points), despite guideline recommendations for PCI in such patients. In addition, uninsured patients with STEMI had no significant difference in probability of receiving PCI treatment compared with privately insured patients.

Limitations of the study include a lack of data on postdischarge care, medication, and reasoning why PCI may not have been performed. These data are local to California, limiting overall generalizability.


Niedzwiecki MJ, Hsia RY, Shen Y-C. Not all insurance is equal: differential treatment and health outcomes by insurance coverage among nonelderly adult patients with heart attack. J Am Heart Assoc. 2018;7(11):e008152.