Risk factors for postoperative pneumonia after lung cancer surgery and impact of pneumonia on survival

•Postoperative pneumonia is a common complication following lung cancer surgery.•Strong risk factors are advanced age, previous pneumonia, and chronic lung disease.•Modifiable risk factors include obesity, alcoholism and atrial fibrillation.•Thoracoscopic surgery is associated with lower pneumonia risk than open thoracotomy.•Pneumonia within 30 days predicts decreased survival within 31-365 days and 1-5 years.

ObjectiveLittle is known about risk factors and prognosis for postoperative pneumonia (POP) in patients undergoing therapeutic lung cancer (LC) surgery.MethodsWe followed a nationwide population-based cohort of 7479 patients with LC surgery in Denmark 1995-2011. We used logistic regression analysis to examine risk factors for POP within 30 days after surgery. Subsequent survival in patients with POP was analyzed with Cox regression.ResultsWe identified 268 (3.6%) patients with POP. Important risk factors included advanced age (age ≥80 years: (adjusted odds ratio [aOR] = 3.64; 95% CI: 2.17-6.12) as compared to patients aged 50-59 years), previous pneumonia (aOR = 2.68; 95% CI: 2.02-3.56), obesity (aOR = 1.91; 95% CI: 0.99-3.69), chronic pulmonary disease (aOR = 1.90; 95% CI: 1.40-2.57), alcoholism (aOR = 1.56; 95% CI: 0.81-3.01), and atrial fibrillation (aOR = 1.42; 95% CI: 0.82-2.45). Overall thoracoscopic surgery halved the risk of POP and the highest risk of POP was seen in pneumonectomy performed in open thoracotomy. Among patients surviving the 30-day postoperative period, 31-365 day mortality was 21.6% in POP patients vs. 16.8% in non-POP patients, and 1-5-year mortality was 62.2% vs. 53.0%. Adjusted 31-365 day hazard ratio (HR) of death with POP was 1.31 (95% CI: 1.00-1.73), and 1-5 year HR was 1.22 (95% CI 0.98-1.53).ConclusionMajor risk factors for POP following LC surgery are advanced age, previous pneumonia, obesity, chronic pulmonary disease, alcoholism, and atrial fibrillation. POP is a clinical marker for decreased LC survival.