Medicare Part D implementation and associated health impact among older adults in the United States

Objective: Studies have shown that the implementation of Medicare Part D (Part D) in 2006 is associated with reduced out-of-pocket expenses and improved drug adherence for Medicare beneficiaries. However, little is known on the change in health outcomes that are associated with this policy. The purpose of the study is to examine the effects of Part D implementation on health outcomes among the U.S. older adults.

Methods: Data were initially drawn from the 2004-2008 Health and Retirement Study (HRS). Data from the respondents who participated in the HRS 2005-2007 Prescription Drug Study and consented to share their Medicare claims were analyzed (N=746). A panel ordered logistic regression with a difference-in-differences approach was used to examine the Part D effect on patients’ health outcomes before and after Part D implementation, controlling for patient sociodemographic characteristics. Variable selection for analysis models was guided by the Andersen’s model of healthcare utilization.

Results: People with continuous Part D enrollment from 2006-2008 were (OR=0.48; p<.05) less likely to have a worse self-rated health than those who were not enrolled in Part D. A higher Charlson Comorbidity Index score was associated with a higher likelihood of having worse self-rated overall health (OR=1.12; p<.001), worse mental health (OR=1.17; p<.001), and worse activity daily living impairment (OR=1.36; p<.001).

Conclusion: The Part D implementation appears to have a positive effect on older adults’ overall health status. Reducing healthcare cost likely encourages older adults to utilize more needed medications than before, which, in turn, helps maintain better health.