Fibrinogen in early admission is an independent risk factor for early deep venous thrombosis in elderly patients with hip fracture.

Deep venous thrombosis (DVT) is a common and serious complication in elderly patients with hip fracture. This retrospective cohort study evaluated whether fibrinogen (FIB) measured within 24 h of admission is independently associated with early DVT. A total of 234 consecutive patients aged ≥ 60 years with hip fracture admitted between January 2020 and June 2023 were included. Bilateral lower-extremity Doppler ultrasound was performed within 24 h of admission to diagnose DVT. Fasting blood samples were obtained prior to pharmacologic thromboprophylaxis. Multivariate logistic regression assessed independent risk factors, and receiver operating characteristic (ROC) curve analysis evaluated diagnostic performance. Among 234 patients, 50 developed DVT (21.4%). Fibrinogen levels were higher in the DVT group than in the non-DVT group (4.15 ± 1.11 g/L vs. 3.47 ± 0.84 g/L, P < 0.001). Univariate analysis showed an association between fibrinogen and DVT (OR = 2.12; 95% CI, 1.50-2.99; P < 0.001). After adjustment for age, sex, cerebral infarction, hypertension, time from injury to admission, albumin, and C-reactive protein, fibrinogen remained independently associated with DVT (OR = 1.79; 95% CI, 1.15-2.73; P = 0.01). Fibrinogen ≥ 4.15 g/L was associated with increased risk (adjusted OR = 3.06; 95% CI, 1.33-7.03; P = 0.008). The combined model including fibrinogen, C-reactive protein, and time from injury to admission yielded an AUC of 0.727 (95% CI, 0.650-0.805), whereas D-dimer showed limited diagnostic value (AUC = 0.457). Elevated fibrinogen within 24 h of admission is independently associated with early DVT and may support early risk stratification.