title: Bronchodilation and smoking interaction in COPD: a cohort pilot study to assess cardiovascular risk.
abstract: BACKGROUND
  Smoking and bronchodilator treatment are both extensively studied as key elements in patients with chronic obstructive pulmonary disease. However, little is known about whether or not these elements interact in terms of developing cardiovascular diseases in patients with COPD.
  
  
  OBJECTIVE
  To explore to what extent the risk of developing ischemic cardiovascular disease in COPD patients is mediated by smoking status, use of bronchodilators and--specifically--their interaction.
  
  
  METHODS
  We performed an observational pilot study on a relatively healthy Dutch COPD cohort from a primary care diagnostic center database with full information on spirometry tests, smoking status, bronchodilator use and other prescribed medication. We defined first ischemic cardiovascular events as primary outcome, measured by first prescription of antiplatelet drugs and/or nitrates. Unadjusted analyses by Kaplan-Meier were followed by adjusted Cox' proportional hazards.
  
  
  RESULTS
  845 COPD patients, totaling 2,169 observation years, were included in the analyses. We observed an increased risk for nonfatal ischemic cardiovascular events by smoking (adjusted HR=3.58, p=0.001) and a protective effect of bronchodilators (adjusted HR=0.43, p=0.01). Although the protective effect of bronchodilators appears to be substantially minimized in patients that persist in smoking, we could not statistically confirm a hazardous interaction between bronchodilators and smoking (HR 2.50, p=0.21).
  
  
  CONCLUSIONS
  Our study reveals bronchodilators may protect from ischemic cardiovascular events in a relatively 'healthy' COPD population. We did not confirm a hazardous interaction between bronchodilators and smoking, although we observed current smokers benefit substantially less from the protective effect of bronchodilators.
authors.affiliation: Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. W.vanDijk@aios.umcn.nl
authors.forename: Wouter D
authors.initials: WD
authors.lastname: van Dijk
authors.forename: Jacques W M
authors.initials: JW
authors.lastname: Lenders
authors.forename: Joran
authors.initials: J
authors.lastname: Holtman
authors.forename: Joke
authors.initials: J
authors.lastname: Grootens
authors.forename: Reinier
authors.initials: R
authors.lastname: Akkermans
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Heijdra
authors.forename: Chris
authors.initials: C
authors.lastname: van Weel
authors.forename: Tjard R J
authors.initials: TR
authors.lastname: Schermer
mesh_terms: D000368:Aged; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002318:Cardiovascular Diseases / Q000150:complications* / Q000517:prevention & control; D002319:Cardiovascular System / Q000187:drug effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D012306:Risk; D012907:Smoking / Q000009:adverse effects*
chemical_list: D001993:Bronchodilator Agents