title: The impact of chronic obstructive pulmonary disease on intensive care unit admission and 30-day mortality in patients undergoing colorectal cancer surgery: a Danish population-based cohort study.
abstract: OBJECTIVE
  Chronic obstructive pulmonary disease (COPD) may increase the risk of postoperative complications and thus mortality after colorectal cancer (CRC) surgery, but the evidence is sparse.
  
  
  METHODS
  We conducted this nationwide population-based cohort study in Denmark, including all patients undergoing CRC surgery in the period 2005-2011, identified through medical databases. We categorised the patients according to the history of COPD. We assessed the rate of complications within 30 days. We computed 30-day mortality among patients with/without COPD using the Kaplan-Meier method. We used Cox regression to compute HRs for death, controlling for age, gender, type of admission, cancer stage, hospital volume, alcohol-related diseases, obesity and Charlson comorbidity score.
  
  
  RESULTS
  We identified 18 302 CRC surgery patients. Of these, 7.9% had a prior diagnosis of COPD. Among patients with COPD, 16.1% were admitted postoperatively to the intensive care unit, 1.9% were treated with mechanical ventilation, and 3.6% were treated with non-invasive ventilation. In patients without COPD, the corresponding proportions were 9.7%, 1.1% and 1.1%. The reoperation rate was 10.6% among patients with COPD and 8% among patients with cancer without COPD. 30-day mortality was 13% (95% CI 11.4% to 14.9%) among patients with COPD and 5.3% (95% CI 5.0% to 5.7%) among patients without COPD, corresponding to an adjusted HR of 1.7 (95% CI 1.5 to 2.0).
  
  
  CONCLUSIONS
  COPD is a strong predictor for intensive care unit admission and mortality after CRC surgery.
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Platon
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Erichsen
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Christian Fynbo
authors.initials: CF
authors.lastname: Christiansen
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Lea Kjær
authors.initials: LK
authors.lastname: Andersen
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Sværke
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Montomoli
authors.affiliation: Department of Clinical Epidemiology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Henrik Toft
authors.initials: HT
authors.lastname: Sørensen
keywords: COPD ÀÜ Mechanisms; Clinical Epidemiology