How does drug treatment for diabetes compare between Medicare Advantage prescription drug plans (MAPDs) and stand-alone prescription drug plans (PDPs)?

ABSTRACT: To compare the use of guideline-recommended prescription medications for diabetes among Medicare beneficiaries enrolled in stand-alone prescription drug plans (PDPs) with Medicare Advantage prescription drug plans (MAPDs) in the presence of potential selection bias.Centers for Medicare and Medicaid Services' Chronic Condition Data Warehouse (2006, 2007).Retrospective cross-sectional comparison of drug use and proportion of days covered (PDC) for oral-antidiabetics, ACE-inhibitors/ARBs, and antihyperlipidemics among PDP and MAPD enrollees with diabetes. We estimated "naïve" regression models assuming exogenous plan choice and two-stage residual inclusion (2SRI) models to study endogeneity in choice of Part D plan type.We identified 111,290 diabetics based on ICD-9 codes in Medicare claims from a random 5 percent sample of Medicare beneficiaries in 2005 excluding dual eligibles.The naïve regression models indicated lower probability of drug use for oral-antidiabetics (-4 percent; p < .001) and ACE-inhibitors/ARBS (-2 percent; p = .004) among PDP enrollees, but their PDC was higher (3-5 percent) for all drug classes (p < .001). 2SRI models produced no significant differences in any-use equations, but significantly higher PDC values for PDP enrollees for oral-antidiabetics and ACE-inhibitors/ARBs.We found similar overall use of recommended drugs in diabetes treatment and no consistent evidence of favorable or adverse selection into PDPs and MAPDs.

SUBMITTER: Erten MZ 

PROVIDER: S-EPMC3681243 | biostudies-other | 2013 Jun

REPOSITORIES: biostudies-other