Medication persistence with weekly versus daily doses of orally administered bisphosphonates

To compare medication persistence among patients receiving daily orally administered bisphosphonates with persistence among patients receiving weekly orally administered bisphosphonates to ascertain whether less frequent dosing is associated with better long-term treatment persistence.

A large, longitudinal cohort of female patients (N = 211,319) receiving prescriptions for alendronate or risedronate from approximately 14,000 US retail pharmacies was assessed. Medication persistence was defined as the percentage of patients who continued to take bisphosphonate therapy during each month (that is, having at least 1 day of medication supply in that month) for a 1-year observation period.

The inconvenience and complexity of required dosing procedures with oral bisphosphonate therapy for the prevention and treatment of osteoporosis are thought to be major factors that hinder medication persistence, and poor persistence is associated with suboptimal health-care outcomes. In this study, the percentage of patients continuing to take bisphosphonate therapy steadily declined with both daily and weekly oral treatment regimens during the course of the 12-month observation period. Consistently, however, medication persistence was higher among patients receiving the weekly rather than the daily regimen. Only 56.7% of patients receiving the weekly regimen and only 39.0% of patients receiving the daily regimen continued to take bisphosphonate therapy at month 12 of the study period (P<0.0001).

This study demonstrates that weekly dosing of orally administered bisphosphonates is associated with higher medication persistence than is daily dosing. Nevertheless, more than 40% of patients did not persist with weekly bisphosphonate therapy for at least 12 months. Thus, medication persistence was inadequate even with use of the weekly regimen. Additional research is needed to determine whether persistence can be further improved by extending the dosing interval beyond once weekly.