Purpose: 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.

Conclusion: 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.