Effect of renal dialysis on mortality and complications following hip fracture surgery in elderly patients: A population based retrospective cohort study

Hip fractures in older patients requiring dialysis are associated with high mortality. The primary aim of this study was to evaluate the specific burden of dialysis on 30-day mortality following hip fracture surgery. The secondary aim was to determine the burden of dialysis on overall survival as well as several postoperative complications. A retrospective cohort study was conducted using data from the Korean National Health Insurance Research Database. Patients were aged ≥65 years and underwent hip fracture surgery during the period from 2009 to 2015. To construct a matched cohort, each dialysis patient was matched to 4 non-dialysis patients based on age, sex, hospital type, anesthesia type, and comorbidities. Survival status was determined 30 days after surgery and at the end of the study period. In total, 96,289 patients were identified. Among them, 1614 dialysis patients were included and matched to 6198 non-dialysis patients. During the 30-day postoperative period, there were 102 mortality events in the dialysis group and 127 in the non-dialysis group, for an adjusted hazard ratio of 3.12 (95% confidence interval, 2.42–4.09). Overall, by the end of the study period, there were 1120 mortality events in the dialysis group and 2731 in the non-dialysis group, for an adjusted hazard ratio of 1.97 (95% confidence interval, 1.83–2.1). These findings may be limited by the characteristics of the administrative database. The 30-day mortality rate was 3-fold higher in the dialysis group than in the non-dialysis group, while the overall mortality rate was approximately 2-fold higher in the dialysis group than in the non-dialysis group. These findings suggest that caution in the perioperative period is required in dialysis patients undergoing hip fracture surgery. The results of our study represent only an association between dialysis and mortality. Further studies are necessary to investigate the possible causal effect of dialysis on mortality and complications after hip fracture surgery.