Objective: The U.S. Surgeon General recently recognized the urgent need to improve adherence in postmenopausal osteoporosis and address the suboptimal therapeutic outcomes that may lead to a national health crisis.1 Adherence consists of compliance (measured by medication possession ratio [MPR]) and persistence (proportion of patients on therapy at a given timepoint or time until therapy discontinuation). Although decreasing medication dosing frequency is postulated to improve adherence, only recently have studies examined compliance or persistence with once-weekly versus once-daily bisphosphonates.2–4 Our analysis describes results from three large studies that encompass data from a total of 214,060 patients prescribed bisphosphonate therapy.
Methods: Data from a claims database2 and a retail pharmacy database3,4 were used to compare once-weekly with once-daily alendronate and/or risedronate treatments, for both persistence (≤30 days lapse for refill prescription from last dose2, or proportion of patients on therapy after 12 months3) and compliance (MPR=days of supply/365 days)2,4 during a 1-year period. The claims database largely represented a younger, more affluent population, while the retail pharmacy database represented a full range of age and socioeconomic status.
Results: Persistence was better with once-weekly (44.2–54.6% at 1 year) compared with once-daily treatments (31.7–36.9% at 1 year) but remained suboptimal. The overall proportion of women maintaining sufficient compliance with bisphosphonate treatment to ensure antifracture efficacy (≥80% MPR)5, ranged from 44.8–55.3% in patients receiving weekly medications to just 33.3–40.4% in patients receiving daily medications.
Conclusions: Studies of different patient-level databases show similar results. Namely, less frequent dosing (weekly) of bisphosphonates is associated with higher medication persistence and compliance than daily bisphosphonates. However, weekly treatments remain suboptimal and do not provide patients with adequate clinical benefit. This finding was consistent regardless of whether data from a claims or retail pharmacy database were assessed. Less frequent dosing regimens (such as oral monthly or i.v. quarterly/yearly therapies) and other routes of administration (i.v. bolus and infusion) are currently under investigation.
1. Bone Health and Osteoporosis:A Report of the Surgeon General (2004). http://www.hhs.gov/surgeongeneral/library/bonehealth/content.html. Accessed November 5, 2004.
2. Cramer JA, et al. J Bone Miner Res 2004;19(Suppl. 1):S448 (Abstract M434)
3. Recker RR, et al. J Bone Miner Res 2004;19(Suppl. 1):S172 (Abstract SA407)
4. Ettinger M, et al. Arthritis Rheum 2004;15(Suppl):S513 (Abstract 1325)
5. Caro JJ, et al. Osteoporos Int. 2004;May 27 [Epub ahead of print]
Disclosure Information:
Faculty Member's Name: Deborah T. Gold, PhD
Consultant: GlaxoSmithKline and Roche
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