Postoperative Pneumonia and Aspiration Pneumonia Following Elderly Hip Fractures

Objectives The present study aimed to investigate the incidence of and risk factors for postoperative pneumonia and aspiration pneumonia after hip fracture surgery. Design Retrospective cohort study from 2005 to 2021. Setting Asan Medical Center in Seoul, Republic of Korea. Participants A total 1,208 patients aged >= 65 years who underwent hip fracture surgery. Measurements Postoperative pneumonia was defined as cases with new infiltration on chest x-ray or chest computed tomography (CT) after surgery or confirmed by a pulmonologist's consultation and diagnosis. Aspiration pneumonia was defined as: 1) radiologic findings of hospital-acquired pneumonia on chest radiographs or CT, medical record of aspiration pneumonia confirmed by a pulmonologist's consultation, and history of vomiting or aspiration, or 2) gravity-dependent opacity on chest CT when the history of vomiting or aspiration is ambiguous. Patient demographics, past medical history, pre-injury Koval score, Charlson Comorbidity Index (CCI), blood test results, length of hospital stay, and in-hospital mortality were evaluated. A comparison analysis and binary logistic regression were performed to identify the incidence and risk factors for postoperative pneumonia and aspiration pneumonia. Results Postoperative pneumonia was diagnosed in 47 patients (3.9%), including 20 with aspiration pneumonia (1.7%). In the multivariate analysis, postoperative delirium (odds ratio [OR], 3.42; P < 0.001), American Society of Anesthesiologists (ASA) scores >= 3 (OR, 2.11; P = 0.021), and CCI (OR, 1.21; P = 0.013) were significant risk factors for postoperative pneumonia. Male sex (OR, 3.01; P = 0.017), postoperative delirium (OR, 3.16; P = 0.014), and preoperative serum albumin levels < 3.5 g/dL (OR, 7.00; P = 0.010) were significant risk factors for aspiration pneumonia. Conclusion ASA classification >= 3, higher CCI, and postoperative delirium were the risk factors for postoperative pneumonia. Male sex, postoperative delirium, and lower preoperative serum albumin level were the risk factors for aspiration pneumonia. Thus, physicians should pay attention to patients with the risk factors.