Risk Factors for Postoperative Pneumonia After Lung Cancer Surgery and Impact of Pneumonia on Survival

Objective: Little is known about risk factors and prognosis for postoperative pneumonia (POP) in patients undergoing therapeutic lung cancer (LC) surgery.

Methods: We 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.

Results: We 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).

Conclusion: Major 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.