Mortality and its determinants after hip fracture among the elderly people in Korea: a study of the National Health Insurance Service-Senior Cohort (2002-2013)

Abstract

With an increasing elderly population owing to an increased average life expectancy worldwide, hip fracture has emerged as a major healthcare issue. In Korea, despite the expected increase in the incidence of hip fracture with the rapidly increasing percentage of elderly people aged ≥65 years in the aging population structure as a result of decreased fertility rate, studies on mortality after hip fracture are still lacking. Accordingly, the present study aimed to use the 12-year data of the National Health Insurance Service-Senior Cohort (NHIS-SC) from 2002 to 2013, which represent most of the data in Korea, to analyze the risk of mortality after hip fracture among the Korean elderly population. The study also aimed to perform multi-faceted analysis of factors associated with the risk of mortality, with consideration of patients, treatments, and provider characteristics. Moreover, in undertaking a sex-stratified analysis, the study attempted to consider certain man versus woman characteristics. In this study, 14,273 elderly patients aged ≥65 years who were diagnosed and operated for hip fracture were examined. Cox proportional hazards frailty model was used to identify mortality risk and related factors within 1-year after hip fracture. Results showed that men and women had different factors associated with the risk of mortality. Factors associated with a higher risk of mortality in elderly men were being of older age, being a medical-care aid beneficiary, not participating in national health screening, being a long-term care beneficiary, having ≤16 days of hospital stay, having a higher Charlson comorbidity index (CCI) score, and being treated at a general hospital. Meanwhile, the factors associated with a higher risk of mortality after hip fracture in elderly women were being of older age, residing in Seoul, belonging to the quintile 3 self-employed group, not participating in national health screening, having ≤16 days of hospital stay, having undergone a hip replacement, not having osteoporosis, having a higher CCI score, being treated at a hospital located in a non-metropolitan area, and being treated at a hospital with less than one form of medical imaging equipment available for use. By identifying factors associated with the risk of post-hip fracture mortality in elderly Korean patients, the present study may provide basic data for raising awareness on the seriousness and importance of hip fractures. Moreover, the findings may provide evidence for public health policy makers to establish effective policies to prevent the incidence of hip fracture and to reduce mortality after hip fracture based on sex characteristics. Follow-up studies that consider factors not included in the present study, such as health behavior and disease severity, are required.