First-year Medicare Part D prescription drug benefits: medication access and continuity among dual eligible psychiatric patients.

Objective: This study provides national data on medication access and continuity problems experienced during the first year of the Medicare Part D prescription drug program, which was implemented on January 1, 2006, among a national sample of Medicare and Medicaid "dual eligible" psychiatric patients.

Method: Practice-based research methods were used to collect clinician-reported data across the full range of public and private psychiatric treatment settings. A random sample of psychiatrists was selected from the American Medical Association Physician Masterfile. Among these physicians, 1,490 provided clinically detailed data on a systematically selected sample of 2,941 dual eligible psychiatric patients.

Results: Overall, 43.3% of patients were reported to be unable to obtain clinically indicated medication refills or new prescriptions in 2006 because they were not covered or approved; 28.9% discontinued or temporarily stopped their medication(s) as a result of prescription drug coverage or management issues; and 27.7% were reported to be previously stable on their medications but were required to switch medications. Adjusting for case mix to control for sociodemographic and clinical confounders, the predicted probability of an adverse event among patients with medication access problems was 0.64 compared to 0.36 for those without access problems (P < .0001). All prescription drug utilization management features studied were associated with increased medication access problems (P < .0001). Adjusting for patient case mix, patients with "step therapy" (P < .0001), limits on medication number/dosing (P < .0001), or prior authorization (P < .0001) had 2.4 to 3.4 times the increased likelihood of an adverse event.

Conclusions: More effective Part D policies and management practices are needed to promote clinically safer and appropriate pharmacotherapy for psychiatric patients to enhance treatment outcomes.