Measuring the impact of the Affordable Care Act with Big Data from electronic health records

Cloud-based health information technologies are an accurate, efficient, and rich data source for monitoring local, national and seasonal health trends.  More specifically, modern electronic health records (EHR) and billing systems provide public health officials and researchers a timely view of local and national healthcare trends, including the impact of public policy. We used claims data tied to an EHR to measure the impact of the Affordable Care Act’s individual mandate on ambulatory healthcare providers.

Claims data from the billing portion of an EHR was used to develop a study cohort of providers who had visits documented prior to January 2011. The study datasets are based on a 29 million ambulatory visits per year (2013 and 2014) across the United States.  These visits represent 10 million patient-provider relationships, for 16 thousand providers.  We evaluated whether requiring insurance coverage increased utilization for these providers, whether providers saw an increase in new patients, and whether payer mix differed by a state’s status on expanding Medicaid eligibility requirements.

Visits to providers did not change and the proportion of visits from new patients increased only slightly for primary care. As a proportion of all patient visits, visits from Medicaid increased in states that expanded Medicaid, but decreased in states that did not expand Medicaid. In expansion states, visits increased for patients transitioning from uninsured to commercial or Medicaid. In non-expansion states, visits increased only for patients transitioning from uninsured to Medicaid, but not patients transitioning from uninsured to commercial.