Preoperative Lower Respiratory Tract Infection and Postoperative Mortality in Elderly Hip Fracture Patients: A Retrospective Cohort Study

Abstract Background Preoperative lower respiratory tract infection (LRTI) is common in elderly hip fracture patients, but its prognostic significance remains understudied. We aimed to investigate whether preoperative LRTI is independently associated with postoperative mortality in this population. Methods This retrospective cohort study included 1,922 elderly patients (≥ 60 years) who underwent hip fracture surgery at a single Level I trauma center between 2015 and 2021. Preoperative LRTI was identified from medical records according to European guidelines. The primary outcomes were 30-day and 1-year all-cause mortality. Hierarchical Cox regression models (Models 1–5) were used to sequentially adjust for demographics, nutritional and inflammatory status, comorbidities, surgical factors, and postoperative complications. Subgroup analyses were performed. Results Preoperative LRTI was present in 319 patients (16.6%). In fully adjusted models, preoperative LRTI was independently associated with increased 30-day mortality (HR 2.68, 95% CI 1.67–4.33) and 1-year mortality (HR 1.71, 95% CI 1.30–2.26). Patients with preoperative LRTI also had significantly higher rates of postoperative cardiac events (8.8% vs. 2.9%) and new-onset pneumonia (21.6% vs. 6.8%). In exploratory subgroup analyses the association appeared stronger in patients with low neutrophil-to-lymphocyte ratio (NLR), although this finding requires validation in future studies. Conclusions Preoperative LRTI is an independent risk factor for both short- and medium-term mortality in elderly hip fracture patients. Preoperative LRTI should be actively screened for and incorporated into preoperative risk stratification. Future multicenter prospective studies are needed to validate these findings and determine whether preoperative optimization can improve outcomes.