Abstract
Background: Euthyroid Sick Syndrome (ESS) is a clinical condition characterized by reduced free triiodothyronine (FT3) levels in response to acute or chronic stress. Proximal femur fractures in geriatric patients are associated with high morbidity and mortality rates and ESS may influence outcomes in this population. This study aimed to investigate the role of ESS as a predictor of complications in elderly patients with hip fractures, analyzing its association with inflammatory and nutritional markers, including the Monocyte-to-Lymphocyte Ratio (MLR), Controlling Nutritional Status (CONUT) score and Hemoglobin, Albumin, Lymphocyte, and Platelet (HALP) score. Materials and Methods: We conducted a single-center retrospective analysis of patients aged 65 and older who were admitted with proximal femur fractures requiring surgical intervention. Thyroid hormone profiles, inflammatory markers and other clinical variables were analyzed preoperatively (T0) and on the first (T1) and third (T2) postoperative days. Logistic regression was used to identify predictors of complications and transfusion requirements. Results: The study included 103 patients (72 men, 31 women; mean age 85 ± 6.27 years). ESS was present in 30 patients (29%) and was associated with longer surgery duration (83.9 ± 35.5 vs. 68.9 ± 21.3 min; p = 0.042). At admission (T0), ESS patients had lower FT3 (1.91 ± 0.25 vs. 2.75 ± 0.28 pmol/L; p < 0.001) and higher TSH (1.55 ± 0.75 vs. 1.20 ± 0.80 mIU/L; p = 0.057). Postoperatively, MLR was significantly altered at T1 (p = 0.026) and T2 (p = 0.040). ESS was a significant predictor of complications at T0 but lost significance postoperatively, while MLR emerged as a key predictor at T2 (p = 0.003). Logistic regression confirmed MLR at T2 as an independent predictor of complications. Hemoglobin levels at T0 (p < 0.001), T1 (p < 0.001), and T2 (p < 0.001), along with albumin at T1 (2.67 ± 0.34 vs. 2.94 ± 0.33 g/dL; p = 0.001) and calcium at T1 (p = 0.006), were significant predictors of transfusion requirements. Nutritional and inflammatory scores were not predictive. Conclusions: ESS is a significant initial predictor of complications in geriatric patients with hip fractures, but inflammatory markers such as MLR assume greater relevance in the postoperative period. These findings emphasize the importance of monitoring ESS and MLR to enhance risk stratification and guide personalized management strategies.