Volume 49 | Number 2 | April 2014

Abstract List

Elham Mahmoudi, Gail A. Jensen Ph.D.


To evaluate whether edicare Part D has reduced racial/ethnic disparities in prescription drug utilization and spending.


Nationally representative data on white, frican merican, and ispanic edicare seniors from the 2002–2009 edical xpenditure anel urvey are analyzed. Five measures are examined: filling any prescriptions during the year, the number of prescriptions filled, total annual prescription spending, annual out‐of‐pocket prescription spending, and average copay level.

Study Design

We apply the nstitute of edicine's definition of a racial/ethnic disparity and adopt a difference‐in‐difference‐in‐differences () estimator using a multivariate regression framework. The treatment group consists of Medicare seniors, the comparison group, adults without edicare aged 55–63 years.

Principal Findings

Difference‐in‐difference‐in‐differences estimates suggest that for frican mericans Part D increased the disparity in annual spending on prescription drugs by $258 ( = .011), yet had no effect on other measures of prescription drug disparities. For ispanics, estimates suggest that the program reduced the disparities in annual number of prescriptions filled, annual total and out‐of‐pocket spending on prescription drugs by 2.9 ( = .077), $282 ( = .019) and $143 ( < .001), respectively.


Medicare Part D had mixed effects. Although it reduced Hispanic/white disparities related to prescription drugs among seniors, it increased the frican merican/white disparity in total annual spending on prescription drugs.