Compliance with drug therapies for the treatment and prevention of osteoporosis.

Objectives: This study used paid claims data from real-world treatment settings to investigate the impact of hormone replacement therapy (HRT), bisphosphonate and raloxifene on patients with a recorded diagnosis of osteoporosis. Methods: Data from a large health insurer were used to identify 58,109 osteoporosis patients who initiated drug therapy for osteoporosis. Multivariate statistical models were developed for duration of therapy, compliance at 1 year, time to discontinuation or a change in therapy, health care costs and risk of fracture over 1 year. Results: One-year compliance rates were below 25% for all osteoporosis therapies. The mean unadjusted duration of continuous therapy was 221 days for raloxifene, 245 days for bisphosphonate, 262 for estrogen-only and 292 days for estrogen plus progestin. Raloxifene patients were consistently less compliant than estrogen-only patients after adjusting for differences in patient characteristics. Estrogen plus progestin patients were generally more compliant while bisphosphonate did not differentiate from estrogen-only. Compliance reduced the risk of hip fracture (o .r. = 0.382, P< 0.01) and vertebral fracture (o.r. = 0.601, P< 0.05). Compliant patients used fewer physicians services (−US$ 56, P< 0.0001), hospital outpatient services (−US$ 38, P< 0.05) and hospital care (−US$ 155, P< 0.01). Bisphosphonate patients were twice as likely as estrogen-only patients to experience vertebral, Colles and other fractures and experienced higher health care costs (+US$ 420, P< 0.01). The effectiveness of both raloxifene and bisphosphonate medications relative to estrogen-only improved significantly with the age of the patient. Conclusions: Compliance with drug therapies for osteoporosis over 1 year is poor leaving patients at risk for fractures and higher health care costs. © 2004 Elsevier Ireland Ltd. All rights reserved.