title: Smoking status and 30-day mortality in patients undergoing pulmonary resections.
abstract: BACKGROUND
  Smoking status has not been shown to have a significant effect on 30-day mortality after potentially curative resectional surgery for non-small-cell lung cancer, and this is reflected in the guidelines of the National Institute for Health and Care Excellence in the United Kingdom.
  
  
  METHODS
  A validated prospective thoracic surgery database of consecutive patients undergoing potentially curative resection at a single institution was analyzed. Univariate and propensity analyses of 30-day mortality were performed.
  
  
  RESULTS
  Univariate analysis identified 30-day mortality as significantly lower in current smokers (n = 852, 2.6%) than ex-smokers (n = 1587, 4.9%; p < 0.001). Propensity 1:1 matching of male patients resulted in 727 current smokers being matched to 727 ex-smokers. The overall balance test (χ(2 )= 6.1, degrees of freedom = 8, p = 0.6), indicated a good match. After propensity matching, the mortality rate was significantly higher in current smokers (p = 0.01).
  
  
  CONCLUSIONS
  Current smokers and ex-smokers are statistically different with regard to risk factors for death. This results in a skewed population of current and ex-smokers undergoing resection for non-small-cell lung cancer. Development of a risk model for 30-day mortality revealed that current smokers have a lower predicted 30-day mortality than ex-smokers, a finding that is counterintuitive. Propensity matching balanced the current and ex-smoker groups to correct for group differences. Analysis after propensity matching identified current smoking as a significant factor determining 30-day mortality.
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Mediratta
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK mpoullis@hotmail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Poullis
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000209:etiology / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D016009:Chi-Square Distribution; D016208:Databases, Factual; D004739:England; D005260:Female; D006801:Humans; D016015:Logistic Models; D008175:Lung Neoplasms / Q000209:etiology / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011013:Pneumonectomy / Q000009:adverse effects / Q000401:mortality*; D057216:Propensity Score; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000401:mortality*; D016540:Smoking Cessation; D000074606:Smoking Prevention; D013997:Time Factors; D016896:Treatment Outcome
keywords: Cancer; Hospital mortality; Pneumonectomy; Prognosis; Risk factors; Smoking; non-small-cell lung