Context: Persistence with osteoporosis treatment is poor but is important for maximum benefit.

Objective: To assess the impact of physician reinforcement using bone turnover markers (BTMs) on persistence with risedronate treatment.

Design and Setting: 1-year multinational prospective, open-label, blinded study in 171 osteoporosis centers in 21 countries.

Patients: 2382 postmenopausal women (65-80 years) with spine/hip T-score -2.5 or T-score -1.0 with a low-trauma fracture.

Intervention: Calcium 500 mg/d, vitamin D 400 IU/d, and risedronate 5 mg/d for 1 year. Centers were randomized to reinforcement (RE+) or no reinforcement (RE-). At 13 and 25 weeks, reinforcement based on urinary N-telopeptide of type I collagen [uNTX] change from baseline was provided to the RE+ patients using the following response categories: good (>30% decrease), stable (-30% to +30% change) or poor (>30% increase).

Main Outcome Measures: Persistence assessed with electronic drug monitors.

Results: In the overall efficacy population (n = 2302), persistence was unexpectedly high and was similar for both groups (RE-, 77%; RE+, 80%; P = 0.160). A significant relationship between the type of message and persistence was observed (P = 0.017). Compared with RE-, intervention based on a good BTM response was associated with a significant improvement in persistence (HR=0.71; 95% CI, 0.53-0.95). Persistence was unchanged (HR=1.02; 95% CI, 0.74-1.40) or lower (HR=2.22; 95% CI, 1.27-3.89) when reinforcement was based on a stable or poor BTM response, respectively. Reinforcement was associated with a lower incidence of new radiologically determined vertebral fractures (OR=0.4; 95% CI, 0.2-1.0).

Conclusions: Reinforcement using BTMs influences persistence with treatment in postmenopausal women with osteoporosis, depending on the BTM response observed.