Association of serum selectins with outcomes in older adults following hip fracture surgery: a 3-year follow-up study

Background Hip fractures represent a critical public health challenge for older adults, often leading to severe mobility decline and high long-term mortality. Selectins (E-, L-, and P-selectin) are cell adhesion molecules that play complementary roles in inflammation, hematopoiesis, and bone remodeling; however, their prognostic value in orthopedic trauma remains largely unexplored. Methods A 3-year, single-center, observational cohort study was conducted involving patients older than 60 years who underwent surgical intervention for primary, low-energy hip fractures between June 2019 and June 2022. Fasting peripheral venous blood samples were collected on the first morning after admission to quantify serum selectin levels using ELISA. Multivariable Cox and Logistic regression in the full cohort served as the primary analysis, complemented by a 1:1 propensity-score-matched case-control comparison, Receiver Operating Characteristic (ROC) curve analysis for risk stratification, and Kaplan–Meier survival curves. Results The final analysis included 431 patients, comprising 302 patients who survived >3 years and 129 who survived ≤3 years. In the fully adjusted multivariable model, above-cutoff P-selectin was an independent predictor of 3-year mortality (HR = 3.167, 95% CI: 2.170–4.622; p < 0.001). In a 1:1 propensity-score-matched case-control subset ( n = 232; 116 pairs), patients who died within 3 years exhibited significantly higher preoperative P-selectin levels than survivors (median 4.18 [IQR 0.98–18.21] vs. 1.32 [0.43–7.51] ng/mL; p < 0.001). Using the optimal ROC cutoffs, the above-cutoff P-selectin group demonstrated a markedly elevated 3-year mortality rate (58.67% vs. 23.88%; RR = 2.46, 95% CI: 1.88–3.20; p < 0.001) and a significantly lower 3-year independent ambulation rate (38.67% vs. 65.73%; RR = 0.59, 95% CI: 0.44–0.79; p < 0.001) compared with the below-cutoff group. Patients with above-cutoff E-selectin also experienced a significantly higher 3-year mortality rate (38.13% vs. 26.03%; RR = 1.46, 95% CI: 1.10–1.95; p = 0.01). In multivariable analyses of the full cohort, above-cutoff P-selectin was an independent predictor of both mortality (HR = 3.167; p < 0.001) and a decreased likelihood of independent ambulation (OR = 0.346; p < 0.001). Above-cutoff E-selectin was associated with mortality in the univariable analysis (HR = 1.569; p = 0.012), but this association was attenuated and no longer statistically significant after multivariable adjustment (HR = 1.397; p = 0.072). L-selectin did not show a statistically significant impact on any clinical endpoint. Conclusions Elevated preoperative serum P-selectin is an independent predictor of long-term mortality in older adults following hip fracture surgery. P-selectin may also serve as a potential prognostic indicator for poor functional recovery and a failure to regain independent ambulation, although this association was attenuated among 3-year survivors and should be interpreted in the context of the competing risk of death. The univariable association between E-selectin and mortality did not persist after multivariable adjustment and requires confirmation in larger cohorts.