Background: Despite considerable progress in the treatment of acute myocardial infarction (AMI), major disparities in care remain for the uninsured. Lack of insurance is associated with delays in seeking emergency care for AMI, and uninsured patients are less likely to receive guideline-directed medical therapy, invasive cardiac procedures, and have higher mortality rates than their insured counterparts. In 2014, Medicaid eligibility was expanded under the ACA, and millions of low-income adults gained insurance coverage in over 30 states. However, little is known about Medicaid expansions’ impact on the quality and outcomes of inpatient care for AMI.
Methods: We studied 325,343 MI patients under 65 years of age treated at 860 hospitals in the ACTION-GWTG Registry between 2012 and 2016. Expansion states were those that implemented ACA Medicaid expansion during 2014. Our pre-expansion period included the two years prior to expansion (1/1/2012 to 12/31/2013) and our post-expansion period included the two years following expansion (1/1/2015 to 12/31/2016). We first characterized trends in AMI hospitalizations by insurance status during the study period in expansion and non-expansion states. We then identified a low-income cohort, defined as being covered by Medicaid or uninsured, and assessed the association between state expansion status and quality and outcome measures stratified by time periods using hierarchical logistic regression models.
Results: In our overall cohort, from 2012 to 2016, the proportion of hospitalized AMI patients insured by Medicaid increased by 6.9% in expansion states (7.5% to 14.4%) and 0.4% in non-expansion states (6.2% to 6.6%). Uninsured hospitalizations also declined more in expansion states (18% to 8.4%) than in non-expansion states (25.6% to 21.1%). Our low-income cohort included 55,737 patients - 38,786 were uninsured and 16,951 were insured with Medicaid. Prior to expansion, states that eventually expanded Medicaid were more likely to provide defect free AMI care (all performance measures followed for eligible patients) compared with non-expansion states (aOR 1.26, 95% CI 1.10-1.45, p<0.001). In the post-expansion period, there was no significant difference in defect free AMI care (aOR 1.02, 95% CI 0.89-1.16, p=0.83, p for interaction<0.001). In addition, patients in expansion and non-expansion states had similar rates of in-hospital death both during the pre-expansion period (aOR 0.95, 95% CI 0.79-1.13, p=0.56) and the post-expansion period (aOR 1.03, 95% CI 0.87-1.24, p=0.71, p for interaction=0.48).
Conclusions: States that elected to expand Medicaid did not experience significant improvements in AMI care quality or in-hospital mortality compared with non-expansion states.