title: Use of cardioselective β-blockers and overall death and cardiovascular outcomes in patients with COPD: a population-based cohort study.
abstract: OBJECTIVE
  Use of β-blockers (BBs) in patients with chronic obstructive pulmonary disease (COPD) and cardiovascular diseases is supported by increasing evidence. However, most of these studies focused on the survival outcome and used a non-active comparison, prevalent-user design. We aimed to examine the risk of overall death and cardiovascular outcomes associated with use of cardioselective BBs using an active comparison, incident cohort approach.
  
  
  METHODS
  We identified COPD patients initiating cardioselective BBs or non-dihydropyridine calcium channel blockers (CCBs) between 2007 and 2011 in the population-based Taiwan database. A Cox regression model was applied to estimate hazard ratios (HRs) for overall death, cardiovascular death, and cardiovascular events comparing cardioselective BBs and non-dihydropyridine CCBs after propensity score matching. We also conducted sensitivity analyses to quantify the unmeasured confounding effect from COPD severity.
  
  
  RESULTS
  A total of 107,902 patients were included. Cardioselective BBs were associated with a modest, lower risk of overall death (HR, 0.85; 95 % CI, 0.81-0.88). The reduced risk of overall death, however, was vulnerable to distribution of COPD severity and was easily weakened with lower prevalence of severe COPD patients in the initiators of cardioselective BBs and higher prevalence of severe COPD patients in the initiators of non-dihydropyridine CCBs. No excess benefit for cardiovascular death (HR, 1.05; 95 % CI, 0.97-1.13) or cardiovascular events (HR, 0.98; 95 % CI, 0.94-1.03) was detected.
  
  
  CONCLUSIONS
  The present study demonstrated a potential effect of confounding by COPD severity and therefore did not suggest an association between use of cardioselective BB and survival benefit in COPD patients.
authors.affiliation: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02120, USA.
authors.forename: Yaa-Hui
authors.initials: YH
authors.lastname: Dong
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, 7, Chung-Shan South Road, Taipei, 10002, Taiwan. chiahsuin@yahoo.com.|Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, 10055, Taiwan. chiahsuin@yahoo.com.
authors.forename: Chia-Hsuin
authors.initials: CH
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, 7, Chung-Shan South Road, Taipei, 10002, Taiwan.
authors.forename: Li-Chiu
authors.initials: LC
authors.lastname: Wu
authors.affiliation: Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, 10055, Taiwan.
authors.forename: Mei-Shu
authors.initials: MS
authors.lastname: Lai
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000401:mortality; D012720:Severity of Illness Index
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers
keywords: Cardioselective β-blockers; Cardiovascular outcomes; Chronic obstructive pulmonary disease; Non-dihydropyridine calcium channel blockers; Overall death