OBJECTIVE: To report outcomes of geriatric patients undergoing hip fracture surgery or arthroplasty with or without preoperative pneumonia and to evaluate the influence of pneumonia severity on patient prognosis. METHODS: In this single center retrospective study, we included geriatric patients (≥60 years old) who had undergone hip fracture surgery or arthroplasty at Peking University People's Hospital from January 2008 to September 2018. Patients with fractures caused by neoplasms or patients with incomplete clinical data were excluded. Using logistic regression and the CURB-65 (confusion, uremia, respiratory rate, blood pressure, and age ≥65 years) score as a prediction tool of 1-year mortality, the effect of preoperative pneumonia on 1-year mortality was evaluated. Survival of patients with different response to pneumonia-specific therapy and survival of patients with different pneumonia severity (evaluated with CURB-65 score) were analyzed using Cox regression. RESULTS: A total of 1386 patients were included; among them, 109 patients (7.86%) were diagnosed with preoperative pneumonia. Outcomes were evaluated in August 2019 (at least 1 year after surgery for all patients). Compared to patients without preoperative pneumonia, patients with this condition had higher 30-day mortality (11.9% vs 5%, P = 0.002) and 1-year mortality rates (33.9% vs 16.3%, P < 0.001) and higher incidence of acute heart failure (7.3% vs 3.4%, P = 0.034) and acute kidney injury (5.5% vs 1.8%, P = 0.009). In multivariate regression, preoperative pneumonia was identified as an independent predictor of 1-year mortality (odds ratio [OR], 1.45; 95% confidence interval [CI] 1.39-3.52; P = 0.021), with other factors including age (≥84 years, OR, 1.46; 95% CI 1.08-1.60; P = 0.027), body mass index (<18.5 kg/m2 , OR 2.23; 95% CI 1.52-3.17, P < 0.001), anesthesia type (regional, OR 0.87; 95% CI 0.19-0.97, P = 0.042), preoperative pneumonia (OR 1.45; 95% CI 1.39-3.52; P = 0.002), congestive heart failure (OR 2.05, 95% CI 1.57-6.21, P < 0.001), chronic kidney disease (OR 1.73; 95% CI 1.50-2.62; P < 0.001). There was a trend of increased 1-year mortality as the CURB-65 score elevated (P for trend = 0.006). Cox regression reveals a higher risk of mortality in patient with preoperative pneumonia, especially in patients with no radiologic improvements after therapy (log-rank, P = 0.035). Analysis of the impact of pneumonia severity on patient survival using Cox regression reveals that a CURB-65 score ≥3 indicated a lower rate of survival (CURB-65 score of 3: hazard ratio [HR] 3.12, 95% CI 1.39-7.03, P = 0.006; score of 4: HR 3.41, 95% CI 1.69-6.92, P = 0.001; score of 5: HR 6.28, 95% CI 2.95-13.35, P < 0.001). CONCLUSION: In this single center retrospective study, preoperative pneumonia was identified as an independent risk factor of 1-year mortality in geriatric patients undergoing hip fracture surgery or arthroplasty. A CURB-65 score ≥3 indicated a higher risk of mortality.