Association of Bone Density Monitoring in Routine Clinical Practice With Anti-Osteoporosis Medication Use and Incident Fractures: A Matched Cohort Study

Routine bone mineral density (BMD) monitoring of individuals during the initial 5 years of anti-osteoporosis treatment is controversial. Using a registry-based cohort from the Province of Manitoba, Canada, we compared anti-osteoporosis medication use and fracture outcomes in women with versus without BMD monitoring receiving anti-osteoporosis medication. We identified 4559 women aged 40 years and older receiving anti-osteoporosis therapy with serial BMD testing (monitoring) within 5 years (mean interval 3.2 years) and 4559 propensity score–matched women without BMD monitoring. We assessed anti-osteoporosis medication use over 5 years from a population-based retail pharmacy database. Incident fractures to 10 years from health services data. During median 10 years observation, 1225 (13.4%) women developed major osteoporotic fracture, including 382 (4.2%) with hip fractures. Monitored women had significantly better fracture-free survival for major osteoporotic fracture (p = 0.040; 10-year cumulative risk 1.9% lower, 95% confidence interval [CI] 0.3–3.6%) and hip fracture ( p = 0.001; 10-year cumulative risk 1.8% lower, 95% CI 0.7–2.8%) compared with women who were not monitored. Hazard ratios (HRs) were significantly lower in monitored versus not monitored women for major osteoporotic fracture (HR = 0.89, 95% CI 0.80–0.98) and hip fracture (HR = 0.74, 95% CI 0.63–0.87). Days of medication use, medication persistence ratio, and treatment switching over 5 years were greater in monitored versus not monitored women. At the end of 5 years, more women in the monitored group persisted on treatment and more switched treatment, with switching behavior associated with an observed interval reduction in BMD. In conclusion, our findings suggest a possible role for BMD monitoring after initiating anti-osteoporosis therapy in the routine clinical practice setting. © 2019 American Society for Bone and Mineral Research.