Compliance with drug therapy for postmenopausal osteoporosis.
BACKGROUND
Patient compliance with pharmacotherapy for osteoporosis is typically poor in clinical practice; less frequent dosing with bisphosphonates may improve compliance.


METHODS
Using data from 49 US health plans, we identified all women aged >/=45 years with osteoporosis who initiated therapy with a bisphosphonate, calcitonin, estrogen, or raloxifene. Compliance was examined alternatively in terms of incidence of adherence failure (medication days <80% of possible) and persistence failure (gap in therapy >/=90 days), and was compared across treatment groups using Kaplan-Meier methods and Cox proportional hazards models.


RESULTS
The study population included 18,822 women, 48% of whom initiated weekly bisphosphonate therapy. Overall risk of adherence failure was 47% at 3 months, 70% at 1 year, and 84% at 3 years. Risk of persistence failure was 47% at 1 year, and 77% at 3 years. In multivariate analyses, risk of adherence failure was higher for calcitonin (hazard ratio=2.7 vs weekly bisphosphonate therapy, p<0.01), but comparable for all other therapies. Relative risks of persistence failure were generally similar.


CONCLUSIONS
Approximately three-quarters of women who initiate osteoporosis drug therapy are non-adherent with treatment within 12 months, and almost 50% have discontinued such therapy by this time. Compliance with weekly bisphosphonate therapy is generally no better than that with osteoporosis medications requiring more frequent dosing.
Weycker
D
D
Policy Analysis Inc. (PAI), Four Davis Court, Brookline, MA, 02445, USA. dweycker@pai2.com
Macarios
D
D
Edelsberg
J
J
Oster
G
G
D000368:Aged; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D004164:Diphosphonates / Q000008:administration & dosage; D004334:Drug Administration Schedule; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004812:Epidemiologic Methods; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000150:complications / Q000188:drug therapy*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D010352:Patient Dropouts / Q000706:statistics & numerical data
D050071:Bone Density Conservation Agents; D004164:Diphosphonates