The Influence of Renal Dialysis on All-Cause Mortality in Older Patients with Hip Fracture: a Korean Nationwide Cohort Study

BACKGROUND: The purpose of this study was to analyze the all-cause mortality rate over time after elderly hip fracture in end-stage renal disease (ESRD) patients with dialysis, using a Korean nationwide claims database. METHODS: This retrospective nationwide study identified subjects from the Korean National Health Insurance Service-Senior cohort (NHIS-Senior). The NHIS-Senior (total of 588,147 participants) was constructed by 10% random sampling and was designed to represent the elderly living in Korea. Subjects were patients aged 65–99 years who underwent surgical treatment for femoral neck fractures or intertrochanteric fractures. A generalized estimating equation model with Poisson distribution and logarithmic link function was used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (CIs) to measure associations between renal dialysis and cumulative mortality in various time frames. RESULTS: The total number of patients included in this study was 16,818. These patients were divided into two groups: 116 (0.69%) in the dialysis group and 16,702 (99.31%) in the no-dialysis group. The mean length of hospital stay was 43.87 ± 48.45 days in the dialysis group and 36.29 ± 37.49 days in the no-dialysis group (P = 0.095). The effect of renal dialysis on all-cause mortality was 2.29-fold (aRR; 95% CI, 1.29–4.06; P = 0.005) within 30 days and 1.72-fold (aRR; 95% CI, 1.34–2.21; P < 0.001) within 1-year after hip fracture compared to the no-dialysis group. And, the effect of renal dialysis of in-hospital mortality was 2.72-fold (aRR; 95% CI, 1.71–4.33; P < 0.001) compared to the no-dialysis group. CONCLUSION: Elderly patients who underwent dialysis have very high mortality rates after hip fracture. Therefore, it is considered that postoperative care through multidisciplinary management and understanding of pathophysiology for the ESRD patients is necessary.