Identifying Widely Covered Drugs and Drug Coverage Variation Among Medicare Part D Formularies

Published in: JAMA, The Journal of the American Medical Association, v. 297, no. 23, June 20, 2007, p. 2596-2602

Posted on RAND.org on January 01, 2007

by Chien-Wen Tseng, Carol Mangione, Robert H. Brook, Emmett B. Keeler, R. Adams Dudley

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CONTEXT: Clinicians can find it difficult to know which drugs are covered for their Medicare patients because formularies vary widely among Medicare Part D plans and many states have 50 or more such plans. OBJECTIVE: To determine whether Part D formularies in California (the state with the most Medicare beneficiaries) and Hawaii have at least 1 drug within each of 8 treatment classes for hypertension, hyperlipidemia, and depression that can be identified for clinicians as widely covered by the vast majority of Part D plans. DESIGN AND SETTING: Use of the medicare.gov Web site (March 1-April 15, 2006) to examine 72 California and 43 Hawaii Part D formularies' coverage of 8 treatment classes (angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, -blockers, calcium channel blockers, loop diuretics, selective serotonin reuptake inhibitors, statins, and thiazide diuretics), with evaluation of how often drugs were widely covered (defined as inclusion in 90% of formularies at co-payments of $35 without prior authorization). MAIN OUTCOME MEASURE: Identification of treatment classes with at least 1 widely covered drug. RESULTS: For California, coverage for the 75 drugs examined ranged from 7% to 100%. Despite this variation, 7 of 8 classes (excluding angiotensin II receptor blockers) had at least 1 widely covered drug. Of the 34 widely covered drugs (45%), all but 2 were generic. Restricting widely covered to include 95% or more of formularies at co-payments of $15 or less still resulted in 7 of 8 classes with at least 1 widely covered drug. Overall, 73% of generic drugs and 6% of brand-name drugs were widely covered. Findings were similar for Hawaii. CONCLUSIONS: Formularies varied substantially; however, all but 1 treatment class examined had 1 or more widely covered drugs at low co-payments. Knowing which drugs are widely covered would assist clinicians in prescribing, since not all generic drugs were widely covered. Clinicians should know that few brand-name drugs are widely covered and check coverage before prescribing.

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