Effect of monitoring bone turnover markers on persistence with risedronate treatment of postmenopausal osteoporosis.

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

OBJECTIVE: The objective of the study was to assess the impact of physician reinforcement using bone turnover markers (BTMs) on persistence with risedronate treatment.

DESIGN AND SETTING: This was a 1-yr multinational prospective, open-label, blinded study in 171 osteoporosis centers in 21 countries.

PATIENTS: A total of 2382 postmenopausal women (65-80 yr old) with spine/hip T-score -2.5 or less or T-score -1.0 or less with a low-trauma fracture.

INTERVENTION: Intervention included calcium 500 mg/d, vitamin D 400 IU/d, and risedronate 5 mg/d for 1 yr. Centers were randomized to reinforcement (RE+) or no reinforcement (RE-). At 13 and 25 wk, reinforcement based on urinary N-telopeptide of type I collagen 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 was measured.

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 [hazard ratio (HR) 0.71; 95% confidence interval (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 (odds ratio 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.