title: Risk factors for postoperative pneumonia after lung cancer surgery and impact of pneumonia on survival.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark. Electronic address: simonsendennis@gmail.com.
authors.forename: Dennis F
authors.initials: DF
authors.lastname: Simonsen
authors.affiliation: Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Søgaard
authors.affiliation: Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Imre
authors.initials: I
authors.lastname: Bozi
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Horsburgh
authors.affiliation: Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Reimar W
authors.initials: RW
authors.lastname: Thomsen
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011013:Pneumonectomy / Q000009:adverse effects / Q000706:statistics & numerical data; D011014:Pneumonia / Q000209:etiology / Q000401:mortality*; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality; D011379:Prognosis; D012307:Risk Factors; D015996:Survival Rate; D013908:Thoracotomy / Q000009:adverse effects / Q000706:statistics & numerical data
keywords: Clinical epidemiology; Lung cancer; Postoperative pneumonia; Risk factors; Survival