Serial Presepsin Measurement as a Predictor of In-Hospital Mortality in Older Adults with Hip Fractures

Serial presepsin measurements were evaluated for their prognostic value compared with conventional laboratory markers in predicting in-hospital mortality among older adults with hip fractures. This prospective observational study included 85 patients aged ≥65 years admitted with acute hip fractures between December 2025 and May 2026. Residual serum remaining after routine clinical laboratory sampling was obtained on admission (Day 1), Day 3, and Day 5; serum presepsin was measured by commercial ELISA, and routine parameters (C-reactive protein [CRP], white blood cell count, lymphocytes, monocytes, platelets, and liver enzymes) were analysed in the hospital laboratory. Renal function was assessed by serial creatinine and estimated glomerular filtration rate (eGFR). Patients were classified as survivors or non-survivors according to in-hospital outcome. Temporal trajectories were modelled with a linear mixed-effects model fitted to log-transformed presepsin, receiver operating characteristic (ROC) analysis assessed predictive performance, and internal validity was examined by bootstrap resampling. Of the 85 patients, 68 survived and 17 died during hospitalization; all deaths occurred between hospital days 5 and 12. Presepsin diverged progressively between groups, reaching significantly higher concentrations in non-survivors by Day 5 (median 207.70 vs. 147.21 ng/L; p < 0.001), with a Day 5 group-by-time interaction ratio of 1.76 (95% CI 1.38-2.25; p < 0.001). Day 5 presepsin showed the highest predictive accuracy (AUC = 0.868, 95% CI 0.774-0.945; optimism-corrected AUC 0.866), significantly outperforming CRP (AUC = 0.606; p = 0.003) and platelet count (AUC = 0.485; p < 0.001). The association persisted after adjustment for age, ASA class, fracture type, and eGFR, and Day 5 presepsin added discrimination to a baseline clinical model (ΔAUC 0.125; p = 0.015). The Youden-derived cutoff of 169.54 ng/L was unstable across bootstrap resamples (95% range 169.5-207.7 ng/L). Serial presepsin measurement, particularly on Day 5, is associated with in-hospital mortality in this population; these exploratory findings require external validation before any clinical application can be considered.