Keywords: electronic health records, affordable care act, propensity scores, insurance
We present three studies that demonstrate the ability of electronic health records (EHRs) to assess the impact of the Affordable Care Act on patient health and healthcare utilization. Statistical methods used include propensity score weighting with more than two groups, two-stage logistic regression, and difference-in-differences. The first study validated the use of EHRs in tracking Medicaid coverage status over time. This study used data from >100,000 patients and >1 million visits one year pre-ACA through one year post-ACA. The second study showed changes in diabetes-associated biomarkers 24 months pre- and post-ACA among those who were 1) continuously insured, 2) continuously uninsured, 3) discontinuously insured and 4) uninsured pre-ACA and insured post-ACA. Results show a significantly larger reduction in mean hemoglobin A1c (HbA1c) among 18,189 adult diabetic patients who gained insurance post-ACA relative to those who were continuously insured. The third study assessed racial/ethnic differences in health insurance coverage pre-post ACA. We found improvement in insured visits among all racial/ethnic groups, although disparities remained.