Osteoporosis Medication Use, Adherence, and Outcomes in Elderly Enrolled in Medicare Part D

Abstract

Background: Osteoporosis affects an enormous number of people of both sexes, and osteoporosis-related fractures are costly to treat. Yet osteoporosis is poorly managed and managed differently by sex and residential setting. Therefore, this study aimed to assess the difference in medication use, adherence, and outcomes between men and women and among women, between long-term care (LTC) facility and community residents. Methods: Using the 2006-2008 Chronic Condition Data Warehouse 5% national random sample of Medicare beneficiaries, this retrospective study identified elderly 70 years and older with osteoporosis enrolled in Medicare Part A, B, and D stand-alone prescription drug plans from January 1, 2006 through December 31, 2008, or death. Use of bisphosphonates, calcitonin, parathyroid hormone and selective estrogen receptor modulator was tracked over the 3-year period. Treatment effectiveness was measured as hazard of fracture after treatment initiation. Modified Poisson regression was used for analyzing the effect of sex and residential status on osteoporosis medication use. Cox proportional hazard model was used for analyzing the effect of medication use and adherence on fracture risk. Results: The samples included 96,408 females, 8,465 males and 90,956 females, and 2,083 males and 10,262 females enrolled in Medicare Part D for aims 1, 2, 3, respectively. Utilization was lower among LTC residents (RR 0.89, 95% CI [0.87, 0.91]). Bisphosphonates were prescribed less often to LTC residents (RR 0.79, 95% CI [0.75, 0.83]) compared to among community residents. Prevalence of osteoporosis medication use in men was substantially lower than that in women (25.2% vs. 44.3% in 2006). Good adherence decreased the hazard of fracture in both sexes (HR 0.86, 95% CI [0.75, 0.99]). No difference in either treatment or adherence effect on fracture between men and women existed. Conclusion: Prevalence of osteoporosis medication use is low in elderly women enrolled in Part D whether community dwelling or LTC residents. Elderly men are undertreated for osteoporosis compared to elderly women. There is strong confounding by indication in the effect of osteoporosis medications on the risk of fracture; however, good adherence reduces the risk of fracture. There is no evidence for heterogeneity in treatment response among men and women.