An examination of Medicare Part D plans in California and Hawaii reveals wide variations in drug formularies, but indicates that for many classes of drugs, it is possible to find at least one or more drug that is covered by nearly all Part D plans, according to a study in the June 20 issue of JAMA: The Journal of the American Medical Association.
Nearly 23 million of the 43.9 million eligible Medicare beneficiaries have enrolled in the Medicare Part D prescription drug benefit, according to background information in the article. Because of the number and variety of plans, clinicians often find it difficult to know which drugs are covered by Part D plan formularies. Previous studies indicate that two-thirds of clinicians say they lack familiarity with Part D formularies, and three-fourths have been asked by pharmacies or patients to change a prescription to a different drug so that it would be covered by the patient's plan. The number of Part D plans is increasing, with 1,875 stand-alone prescription drug plans in 2007 compared with 1,429 in 2006. Many states have more than 50 Part D plans. "Wide formulary variation can lead clinicians to inadvertently prescribe drugs that are not covered by insurance or that require a high co-payment, increasing patients financial burden and decreasing medication adherence," the authors write.
Chien-Wen Tseng, M.D., M.P.H., of the John A. Burns School of Medicine at the University of Hawaii, Honolulu, and colleagues conducted a study to determine whether Part D formularies in California (the state with the most Medicare beneficiaries) and Hawaii have at least one drug within each of eight treatment classes for hypertension, hyperlipidemia, and depression that can be identified for clinicians as widely-covered by the vast majority of Part D plans. The researchers used the Web site medicare.gov, from March 1-April 15, 2006, to examine 72 California and 43 Hawaii Part D formularies coverage of eight treatment classes (angiotensin-converting enzyme [ACE] inhibitors, angiotensin II receptor blockers [ARBs], beta-blockers, calcium channel blockers, loop diuretics, selective serotonin reuptake inhibitors, statins, and thiazide diuretics), with evaluation of how often drugs were widely covered (here defined as inclusion in 90 percent or more of formularies at co-payments of $35 or less without prior authorization).
In an analyses of 72 formularies, the researchers found that coverage for 75 specific drugs ranged from 7 percent to 100 percent of formularies and averaged 69 percent across all drugs. Formulary coverage (percentage of formularies covering each drug, averaged across all drugs within a class) was highest for thiazide diuretics (90 percent) and beta-blockers (85 percent), followed by selective serotonin reuptake inhibitors (69 percent), calcium channel blockers (66 percent), ACE inhibitors (66 percent), statins (49 percent), and ARBs (39 percent).