A Markov Model Simulation of the Impact of Treatment Persistence in Postmenopausal Osteoporosis

Background. Osteoporosis is a common disorder of the skeleton that increases bone fragility and the risk of fracture. Bisphosphonates have become the reference treatment for postmenopausal osteoporosis because of their proven efficacy in reducing fracture rates. The effectiveness of bisphosphonates is, however, limited by poor treatment adherence and persistence with treatment. A model has been designed to simulate the impact of improving persistence rates on treatment effectiveness. Methods. The Markov model followed a cohort of patients over 10 years to estimate the total number of incident osteoporotic fractures by age for the overall population of women with diagnosed postmenopausal osteoporosis in France (mean age, 71.1 years +/- 9.6; range, 50-96 years). The impact of clinical efficacy, persistence, and residual treatment effects data on predicted fracture risk was also estimated in the model. Results. Predicted numbers of incident fractures appeared consistent with published data. Compared with no treatment, the relative risk of fracture over 10 years was 0.831 for weekly bisphosphonate treatment with an assumed persistence rate of 51% after 1 year (absolute risk reduction=11.4%). This relative risk decreased to 0.731 (absolute risk reduction=18.1%) if hypothetical full-treatment persistence was achieved. In terms of public health, improving persistence with bisphosphonate treatment by only 20% could have the same impact as a 20.2% increase in clinical efficacy. The benefit associated with improved persistence declines as full persistence is approached. Conclusion. Improving persistence can increase treatment effectiveness. Giving greater priority to persistence interventions might have a greater impact on the health of osteoporotic women than advances in treatment efficacy.