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 dollars 56, P < 0.0001), hospital outpatient services (-US dollars 38, P < 0.05) and hospital care (-US dollars 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 dollars 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.