WASHINGTON — Postmenopausal women with osteoporosis can reduce their risk for fractures by 26% if they stick to their bisphosphonate regimens, Ethel Siris, M.D., reported in a poster presented at an international symposium sponsored by the National Osteoporosis Foundation.
However, that “if” is a very big one, said Dr. S. Siris, director of the metabolic bone diseases program at Columbia University Medical Center, New York.
In a retrospective study of 6,285 women, 48% were compliant in terms of refilling their prescriptions, and 21% were persistent in terms of staying on the medication beyond the 2-year follow-up.
Overall, the relative risk of fracture over a 2-year period was 26% lower among refill-compliant women vs. noncompliant women (9.4% vs. 12.6%) and 21% lower among treatment persistent women vs. nonpersistent women (9.1% vs. 11.6%).
More than half (52%) of the women were noncompliant, based on insufficient refills, and approximately 21% were nonpersistent, defined as having a discontinuation of therapy within the 2-year period.
Data on the pharmaceutical claims of women aged 45 years and older who met the criteria for postmenopausal osteoporosis were taken from the Medstat MarketScan Research Database. The women had received at least one prescription for a bisphosphonate; 85% received alendronate (Fosamax) and 15% received risedronate (Actonel).
Although bisphosphonates are a popular choice for fracture risk reduction in osteoporotic women, their effectiveness depends on compliance for an extended period of time. And compliance is notoriously poor.
“If we actually get people to take these drugs, we might cut as many as 400,000 fractures in a given year,” Dr. Siris said. Studies on less frequent dosing regimens, such as the once-monthly regimen for the newly approved ibandronate (Boniva), suggest they are effective and may improve compliance.
Dr. Siris is a consultant for and has received honoraria from Eli Lilly & Co., Merck & Co., Sanofi Aventis, Procter & Gamble Pharmaceuticals, and Novartis.