Bisphosphonate use and subsequent hip fracture in South Korea

Summary We determined the incidence of second hip fracture and evaluated whether compliant and persistent users of bisphosphonate had a lower incidence of second hip fracture after prior hip fracture, from a national claim registry. Introduction Bisphosphonate is prescribed worldwide for the primary prevention of osteoporotic fracture. However, the association between adherent use of bisphosphonate and prevention of second hip fracture is unclear. Our purpose was to determine whether the adherent use of bisphosphonate was associated with a decreased risk of second hip fracture in South Korea, using a nationwide database. Methods From 2007 to 2011, first and second hip fractures were identified using the ICD-10 and procedure code form from the nationwide database of the Health Insurance Review and Assessment Service. Compliant use of bisphosphonate was defined as a patient medication possession ratio of 80 or more. Persistent users were defined patients with a refill gap of 30 days or less. We compared the incidence of second hip fracture in compliant and persistent users and non-users. Results Among 59,782 patients with first hip fracture, in this study, 1,336 second hip fracture occurred after the initial hip fracture during the study period. The mean age at the first hip fracture was 75.4 years (range, 50 to 100 years). The cumulative 1-year, 2-year, and 3-year incidence of second hip fracture was 1.0 % (552/59,782), 1.9 % (1,123/59,782), and 2.2 % (1,336/59,782), respectively. After multivariate analysis, compliant and persistent use of bisphosphonate was significantly independent protectors for second hip fracture (HR, 0.595; 95 % CI, 0.400–0.885; HR, 0.433; 95 % CI, 0.327–0.573, respectively). Conclusions Compliant and persistent use of bisphosphonate decreases the risk of second hip fracture, in terms of secondary prevention.