Abstract
OBJECTIVE: This study aimed to investigate the association between the serum creatinine-to-cystatin C ratio (CCR) and the prognosis of patients with hip fracture. METHODS: This retrospective cohort study included patients who underwent hip fracture surgery at a tertiary hospital in China between January 2018 and December 2023. CCR was calculated from the preoperative serum creatinine and cystatin C levels. The primary outcome was 1-year mortality after surgery in patients with hip fracture and the secondary outcome was 6-month mortality. The associations between preoperative CCR and prognosis of patients were assessed using Kaplan-Meier curves, Cox regression models, interactions, and stratified analyses. RESULTS: A total of 1914 patients who underwent surgery for hip fracture were included. The mean age of the participants was 73.4 ± 14.0 years and the median CCR was 7.3 (6.3-8.5). The prevalence of 1-year mortality flowing hip fracture surgery was 7.3%. Multivariate Cox regression analysis indicated that a high CCR was independently associated with reduced 6-month mortality [hazard ratio (HR) = 0.51; 95% confidence interval (CI) = 0.31-0.84] and 1-year mortality (HR = 0.61; 95% CI = 0.42-0.90) after adjusting for covariates. In addition, Kaplan-Meier curve analyses indicated that the low CCR group had higher 6-month and 1-year mortality rates (all P<0.0001). Subgroup analyses showed that a high CCR was independently associated with reduced 1-year mortality after hip surgery in patients with diabetes (HR = 0.39; 95% CI = 0.17-0.89), males (HR = 0.48; 95% CI = 0.26-0.86) and those without hypertension (HR = 0.55; 95% CI = 0.32-0.97) or cardiovascular disease (HR = 0.54; 95% CI = 0.34-0.84). CONCLUSION: Our study found that a low CCR was associated with poor prognosis in patients undergoing hip fracture surgery. Further research is needed to clarify the mechanism linking low CCR to poor prognosis in hip fracture patients.