Purpose: Bisphosphonate is associated with a decreased risk of clinical vertebral fractures due to osteoporosis. However, there are limited studies on how poor compliance with bisphosphonate affects the risk of vertebral fractures in a nationwide cohort. We aimed to evaluate whether adherence to bisphosphonate affects the risk of fracture in osteoporosis patients.
<br>Methods: We used the data of the Korean National Health Insurance Service Senior Cohort. A total of 33,315 (medication possession ratio [MPR]: 50) osteoporosis patients were matched using the propensity score matching method: those who received low-dose bisphosphonate and those who received high-dose bisphosphonate. Twenty-two confounding variables, including age, socioeconomic status, medications prescribed, and underlying diseases that may affect the risk of fracture were adjusted for propensity score matching.
<br>The risk of vertebral fracture was assessed by Cox proportional hazards regression.
<br>Results: Patients with a higher MPR showed a decreased vertebral fracture risk than those with a lower MPR (MPR 50 = hazard ratio [HR]: 0.909, 95% confidence interval [CI]: 0.877–0.942, P < 0.001; MPR 70 = HR: 0.874, 95% CI: 0.838–0.913, P < 0.001; MPR 90 = HR: 0.822, 95% CI: 0.780–0.866, P < 0.001). MPR was associated with a decreased clinical vertebral fracture risk in both groups with or without history of fracture. In the subgroup analysis, MPR was associated with a decreased clinical vertebral fracture risk in women, in all age, with or without T2DM, and with or without hypertension.
<br>Conclusion: Higher MPR is associated with a lower clinical vertebral fracture risk. Hazard ratio of MPR 50% was 0.909.
