Association of serum high creatinine-to-albumin ratio with increased 1-year mortality in older patients following hip fracture surgery

Background Creatinine-to-albumin ratio (CAR) was associated with short-term and long-term prognosis in various clinical settings. However, the relation of CAR with prognosis in older patients with hip fracture remains unclear. Methods This retrospective study was performed in older patients undergoing hip fracture surgery in our hospital from January 2018 to December 2023. Serum creatinine and albumin were recorded at admission. The primary outcome was 1-year mortality after surgery in patients with hip fracture. The association between preoperative serum creatinine-to-albumin ratio and 1-year mortality was assessed by Kaplan–Meier curves, Cox regression models, and stratified analyses. Results The mean age of the participants was 79.5 ± 8.1 years and the median CAR was 1.9 (1.5–2.4). The prevalence of 1-year mortality following hip fracture surgery was 8.6%. Multivariate Cox regression analysis indicated that high CAR was independently associated with increased 1-year mortality (hazard ratio = 1.49; 95% confidence interval = 1.02–2.17) after adjusting for covariates. In addition, Kaplan–Meier curve analyses indicated that patients with the high CAR had a higher 1-year mortality than that with low CAR ( p < 0.0001). Subgroup analyses showed that the association was similar across all subgroups. Conclusion The CAR can serve as an independent prognosis indicator for 1-year mortality in older patients following hip fracture surgery. However, researchers are required to confirm the findings in the future.