Serum cystatin C as a biomarker to predict all-cause mortality in geriatrics hip fracture

Abstract

BackgroundCystatin C, a low-molecular-weight protein, belongs to cysteine protease inhibitors produced primarily by nucleated cells. Its serum concentration, independent of sex, age, or muscle mass, is a good predictor of renal dysfunction in older adults. This study evaluated the association between all-cause mortality and preoperative cystatin C levels in hip fractures. Materials and methodsData describing the demographic and clinical characteristics of the patients were gathered specifically from older individuals who had suffered hip fractures. The study used linear and non-linear multivariate Cox regression models to investigate the association between preoperative cystatin C levels and mortality. The analyses were conducted using the R and EmpowerStats software. ResultsIn total, two thousand three hundred and ninety-four patients were included in this study. A total of 790 patients (33 %) died of all causes. The mean follow-up was 37.62 months. The preoperative cystatin C was 0.91 ± 0.41 mg/L. Linear multivariate Cox regression analysis revealed a significant association between preoperative cystatin C level and death, with a hazard ratio (HR) of 2.19 (95 % confidence interval [CI]: 1.72–2.79, P < 0.0001). Nevertheless, the correlation between the variables was inconsistent. A cystatin C concentration of 1.62 mg/L marked a significant change in the non-linear relationship. A preoperative cystatin C level below 1.62 mg/L was found to be significantly linked with an increased risk of mortality (HR = 2.60, 95 % CI: 1.92–3.52, P < 0.0001). The mortality reached its highest point when the preoperative cystatin C level was greater than 1.62 mg/L. After that, the mortality risk did not increase further (HR = 1.54, 95 % CI: 0.98–2.42, P = 0.0588). The non-linear relationship remained consistent in the propensity score-matching sensitive analysis. ConclusionsThe study found a non-linear relationship between preoperative cystatin C levels and mortality in geriatric hip fractures. This suggests that preoperative cystatin C can be used as a predictor of the risk of death. The registration number is ChiCTR2200057323.