OBJECTIVES

Although incidence and risk factors of osteoporotic fracture are well-known, those for subsequent osteoporotic fracture specifically are not well-known. We aimed to analyze the incidence and risk factors for subsequent osteoporotic fracture in South Korea.

METHODS

: We performed a retrospective cohort study using the national Health Insurance Review and Assessment (HIRA) claims database from 2012 through 2017. Study subjects were male and female osteoporosis patients aged 50 years or older who had incident fracture between Jul 1, 2014 and Jul 1, 2015. The incidence rate of subsequent fracture was calculated by identifying patients who had the second event within two years from the incident fracture. To evaluate risk factors for having subsequent fracture, we conducted Cox proportional-hazard model to estimate hazard ratios (HRs) and their 95% confidence interval (CI), with respect to the site of incident fracture (hip, vertebra, and non-vertebra-non-hip (NVNH) (ref)).

RESULTS

: Of the 73,717 patients with an osteoporotic fracture, 13,203 (17.91%) patients had subsequent fracture, consisting 35.9% vertebrae, 3.9% hip, and 60.2% NVNH fractures. The incidence rate of subsequent fracture within two years from incident fracture was 9.96 per 100 person-years. The site of incident fracture was a significant risk factor: hip showed the highest risk of subsequent fracture (HR 7.55; 95% CI 6.95-8.19), followed by vertebrae (HR 1.99; 95% CI 1.91-2.07). The risk of subsequent fracture increased with higher CCI(Charlson Comorbidity Index) score (CCI score ≥5: HR 1.79; 95% CI 1.67-1.91, CCI 1-4: HR 1.33; 95% CI 1.26-1.41).

CONCLUSIONS

: The incidence rate of subsequent osteoporotic fracture in South Korea is similar to or greater than those in the United States and Europe. History of incident fracture at hip significantly increases the risk of subsequent fracture compared to fracture at other sites in osteoporosis patients. Osteoporosis patients with risk factors need management for preventing subsequent fractures.