Effect of the Affordable Care Act on utilization of emergency and primary care

Abstract

The Affordable Care Act (ACA) has considerably reduced the uninsured rate nationally through availability of guaranteed issue private plans (Marketplace) and Medicaid expansion. However, expanding access to health insurance coverage may not be a sufficient incentive for consumers to change their usual setting for care, reduce avoidable use of emergency departments (ED), or increase use of preventive care. One of the core arguments for expansion has been that individuals without coverage may forego preventive care, delay treatment, and subsequently overutilize the ED––leading to worse health outcomes and higher long-run health expenditures. The objective of this dissertation is to investigate the effect of the ACA on substitution between ED and primary care among the newly insured (aim 1), potential delayed effects of coverage gains on avoidable use of the ED (aim 2), and whether high deductibles serve as a barrier to the use of no-cost preventive services (aim 3). Aim 1 uses the linkage between the 2012 National Health Interview Survey and 2013 and 2014 Medical Expenditure Panel Survey to quantify substitution between the ED and primary care settings using linear and multinomial logistic regression models. Aim 2 uses the Healthcare Cost and Utilization Project State Inpatient and Emergency Department Databases for 2008 to 2016 to identify the effect trajectory of coverage gains on avoidable ED use using county-level fixed effects and spatial regression models. Aim 3 uses insurance claims from IBM Health® MarketScan® for 2008 through 2016 to estimate the effect of high deductible health plan enrollment on use of high-value preventive services using difference-in-differences models. This project will provide new understanding of how consumers respond to coverage gains at both the individual and population level with a focus on emergency and primary care services—two ends of the health care spectrum that can often be substitutable, particularly for the newly insured. It will address if and when consumers substitute towards a more appropriate setting for care and also how eliminating cost sharing affects use of preventive services. These insights can be used to refine benefit design, consumer education, and expectations about the costs and health benefits of future reforms.Doctor of Philosoph