Analysis of national annual variation in total patient out-of-pocket Medicare Part D stand-alone prescription drug plan costs from 2007 to 2008.

Objective: This is the first study to compare total Medicare Part D (MPD) stand-alone prescription drug plan (PDP) estimated annual costs (EAC) between 2007 and 2008 in all MPD regions of the US using a patient cohort of Medicare-eligible patients.

Methods: A total of 50 patients were selected at random from a database of Medicare-eligible patients. Each patient profile, based on pharmacy claims data, was entered into the Medicare website and the EAC of each PDP in each of the 34 MPD regions was obtained. The lowest, 25th percentile, median and highest EAC plans were obtained for each patient in each region for 2007 and 2008. Pair-wise, within-region, between-year comparisons were made using the Wilcoxon Signed-Ranks test.

Results: Annual trends were variable between MPD regions. Only the highest EAC showed significant decreases in some regions, while all other comparisons showed no change or an increase in regional costs.

Conclusions: Out-of-pocket Medicare prescription drug costs increased from 2007 to 2008. Increases in plan costs highlight the need for annual re-evaluation of PDP costs so that the patient is able to obtain the lowest cost plan each year. The decrease in the highest cost plan may suggest improvements in formulary coverage.