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We appreciate Dr Singh’s interest in our paper and the thoughtful comments. While we believe our data make a compelling argument that β blockers are regularly tolerated by patients suffering acute exacerbations of COPD and that they may be associated with improved outcomes, we do not advocate their routine use at present and believe this overstates our conclusions.1 We echo Dr Singh’s call for randomised clinical trials in a variety of settings to definitively address the safety and efficacy of β blockers in patients with COPD.
Although observational studies, including ours1–3, have suggested that β blockers are safe and effective in COPD patients with or at risk for cardiovascular disease, these results are not definitive and do not justify a change in clinical practice. Such studies cannot fully account for provider bias in the prescription of β blockers that is inevitable in retrospective analyses, and our results do not support the initiation of these drugs on admission to the hospital. In addition, Dr Singh correctly highlights that there are mechanistic studies that demonstrate adverse effects of β blockers on lung function,4 although for cardioselective agents these effects appear modest.5 Given the current evidence, we do recommend against the routine withholding of cardioselective β blockers from patients with COPD as this may be associated with increased mortality, particularly if the agents are acutely withdrawn.
Most guidelines list COPD as a contraindication to β blocker use although this is largely based on extrapolation of data in patients with asthma and from studies of non-cardioselective agents. Unlike mortality among patients with asthma, however, the most common cause of mortality in patients with COPD is cardiovascular disease. Thus the potential benefits of β blocker therapy are far clearer in this population. There are several mechanisms by which β blocker use during acute exacerbations may reduce mortality1 6 and an important conclusion from our study is that β blockers are well tolerated even when the airway is most compromised. We believe that this finding, along with other observational studies suggesting benefit, sets the stage for randomised trials in outpatients with stable COPD to definitively establish the risk–benefit ratio of β blockers in COPD. If a benefit is observed, such a trial could change practice and we may finally have a drug to save lives in COPD.
Competing interests: None.