Soluble urokinase plasminogen activator receptor biomarker is not a predictor of mortality in high-risk hip fracture patients

Background The soluble urokinase plasminogen activator receptor (SuPAR) is a biomarker of inflammation and immune activation that has been related with mortality in a vast spectrum of diseases in the elderly. Its prognostic value in preoperative evaluation for non-cardiac surgery has been promising. However, up to date there are no studies in high-risk patients undergoing hip fracture surgery. Therefore, we performed this prospective study aims to evaluate the prognostic value of SuPAR and other common clinical, echocardiographic, and blood biomarkers for the 1-year survival of high-risk hip fracture surgery patients. Methods We studied 46 patients with hip fracture that underwent hip fracture surgery from 2019 to 2024. There were 10 men and 36 women, over 65 years of age (mean, 85 +/- 8 years) with at least one high-risk characteristic (dementia, chronic immobilization, age > 90 years). Upon admission, complete clinical and laboratory assessments, including electrocardiogram and cardiac ultrasonography, radiographs, and blood sampling, were conducted. Serum blood levels of SuPAR as well as natriuretic peptides and troponin I were measured. The Katz index of frailty was calculated. The patients were followed for 1 year after admission and hip fracture surgery. At that time, the patients or their relatives were contacted through telephone, and their 1-year survival was documented. Results Overall, 25 (54.3%) patients were dead at 1-year examination. There was no significant difference in baseline values of SuPAR between patients dead or alive at follow-up (6.30 ng/dl [range, 4.95-7.05 ng/dl] vs. 6.25 ng/dl [4.25-9.05 ng/dl], respectively; p value = 0.767), and SuPAR has not been related to 1-year mortality (HR 0.802; 95% CI 0.248-2.595; p value = 0.712). The only univariate and multivariate predictors of survival were age (HR 1.098; 95% CI 1.003-1.181; p = 0.041) and Katz index <= 4 (HR 4.490; 95% CI 1.180-17.093; p = 0.028). Conclusion This study showed that SuPAR is not a predictive factor for 1-year mortality in high-risk patients undergoing hip fracture surgery. Older age and Katz index score <= 4 were the only independent predictors of 1-year mortality. Therefore, although no definite conclusion can be drawn from such a small number of patients, no trend in mortality for this measurement has been observed, suggesting SuPAR and similar biomarkers should not be considered in the evaluation of mortality in high-risk hip fracture patients.