The Role of an Array of Routine Clinical Variables to the Occurrence and Severity of Postoperative Pneumonia in Non–Small Cell Lung Cancer Patients

Background and purpose: Data of an array of preoperative/intraoperative clinical variables may carry significant information for predicting the probability of postoperative pneumonia or chest infection in non–small cell lung cancer (NSCLC) patients. We aimed to investigate the association between those variables and the occurrence of postoperative pneumonia (POP) as well as the severity of POP, based on routine laboratory tests, basic characteristics, and perioperative variables during the in-hospital period. Methods: A consecutive series of NSCLC patients undergoing lung cancer lobectomy at our department from January 2014 and December 2015 was used as the target patient group and stratified into 2 groups: pneumonia (POP) and non-pneumonia (N-POP), according to occurrence of pneumonia after lobectomy in 30 days. The POP was classified into 5 severity grades, based on the Clavien-Dindo complication classification system. Results: Regarding binary logistic regression analysis for risk factors of POP, the following were found to be the independent risk factors of the occurrence of POP: postoperative predicted forced expiratory volume in 1 second [ppoFEV1%; odds ratio (OR): 0.996, 95% confidence interval (CI): 0.993–0.999; P = 0.021]; Charlson comorbidity index (CCI) score >3 (OR: 2.694, 95% CI: 1.462–4.965; P = 0.001); American Society of Anesthesiologists (ASA)score >3 (OR: 2.066, 95% CI: 1.060–4.029; P = 0.033); postoperative predicted diffusion capacity for carbon monoxide of the lung (ppoDlco%; OR: 0.458, 95% CI: 0.090–0.809; P = 0.014); and neutrophil-lymphocyte ratio (NLR; OR: 2.171, 95% CI: 1.721–2.737; P < 0.001). With regard to risk factors analysis of pneumonia severity via ordinal polytomous logistic regression, the following were the independent risk factors: early stage (OR: 0.626, 95% CI: 0.422–0.929, P = 0.020); CCI score >3 (OR: 1.914, 95% CI: 1.058–3.459, P = 0.032); ppoDlco% (OR: 0.638, 95% CI: 0.445–0.914, P = 0.014); and NLR (OR: 1.218, 95% CI: 1.031–1.436, P = 0.020). Conclusion: Among an array of clinical variables in the hospital, major risk factors for POP following LC surgery were ppoFEV1%, ppoDlco%, NLR, ASA score >3, and CCI score>3; meanwhile, ppoDlco%, CCI score>3, NLR, and early tumor stage were the key predictors of POP severity.