High Deductible Health Plans and Use of Free Preventive Services Under the Affordable Care Act.

The Affordable Care Act aimed to increase use of preventive services by eliminating cost-sharing to consumers. However, patients may be unaware of this benefit or they may not seek preventive services if they anticipate that the cost of potential diagnostic or treatment services will be too high, both more likely among those in high deductible health plans. We used nationally representative private health insurance claims (100% sample of IBM MarketScan) for the United States from 2006 to 2018, restricting the data to enrollment and claims for non-elderly adults who were enrolled for the full plan year. The cross-sectional sample (185 million person-years) is used to describe trends in preventive service use and costs from 2008 through 2016. The cohort sample (9 million people) focuses on the elimination of cost-sharing for certain high-value preventive services in late 2010, requiring continuous enrollment across 2010 and 2011. We examine whether HDHP enrollment is associated with use of eligible preventive services using semi-parametric difference-in-differences to account for endogenous plan selection. Our preferred model implies that HDHP enrollment was associated with a reduction of the post-ACA change in any use of eligible preventive services by 0.2 percentage points or 12.5%. Cancer screenings were unaffected but HDHP enrollment was associated with smaller increases in wellness visits, immunizations, and screening for chronic conditions and sexually transmitted infections. We also find that the policy was ineffective at reducing out-of-pocket costs for the eligible preventive services, likely due to implementation issues.