The marginal benefits of invasive treatments for acute myocardial infarction: Does insurance coverage matter?

This paper applies instrumental variable (IV) techniques and estimates the average benefits of invasive surgical treatments for marginal acute myocard ial infarction (AMI) patients by insurance coverage. The study uses data fr om the Agency for Healthcare Research and Qualify's Healthcare Cost and Uti lization project (HC:UP), State Inpatient Databases for the state of Washin gton, for years 1988-1993. We observed differences in average benefits for marginal patients across insurance subpopulations that cannot be explained by differences in measured clinical circumstances. Our empirical results sh ow that the insurance subpopulations with the greatest estimated marginal b enefits are those with the lowest expected payment generosity to providers. Because of the relatively weak explanatory power of our instruments for th ree insurance subpopulations, and because many of the parameter estimates a cross the insurance subpopulations are not statistically different from eac h other, policy recommendations should be approached cautiously. However, o ur application of IV techniques to AMI patients demonstrates the usefulness of this approach to estimate treatment effects across patient populations (e.g, across types of insurance coverage) for medical conditions of interes t to policymakers. These estimates may help determine whether treatments ar e overutilized or underutilized.