To the Editor We read with great interest the recent randomized clinical trial¹ assessing the effect of bisoprolol in patients with chronic obstructive pulmonary disease (COPD) who are at high risk for exacerbation. The study found that bisoprolol did not reduce the number of self-reported COPD exacerbations requiring oral corticosteroids, antibiotics, or both.¹ Although the study provides valuable insights, we would like to express some concerns about the findings.

First, we have serious concerns about the confounding effect of β-blockers in patients with asthma in this study. The association between cardioselective β₁-blockers and the risk of asthma exacerbation remains controversial.^2,3 Although this study excluded patients with an asthma diagnosis before age 40 years, 10.8% and 13.7% of patients with an asthma diagnosis after age 40 years were included in the intervention and control groups, respectively.¹ To avoid the potential adverse effects of bisoprolol on patients with coexisting asthma, further subgroup analysis excluding patients with COPD and concomitant asthma is warranted.

Second, COPD is a significant risk factor for severe COVID-19, and SARS-CoV-2 vaccination is recommended for this population to prevent COVID-19 progression. Although this study conducted a subgroup analysis according to the study period (before, during, and after the COVID-19 pandemic), the effect of SARS-CoV-2 vaccination during and after the pandemic was not assessed. Similarly, the status of other recommended vaccines against pneumococcus, influenza, herpes zoster, and respiratory syncytial virus for patients with COPD needs clarification.

In conclusion, although this study provides important data on the use of bisoprolol for patients with COPD, several key factors require further investigation. The potential effect of concomitant asthma and the influence of various vaccinations, particularly in the context of the COVID-19 pandemic, are critical areas for additional analysis. Addressing these concerns would strengthen the study’s findings and provide more comprehensive guidance for treating patients with COPD who are at high risk of exacerbation.

Corresponding Author: Chih-Cheng Lai, MD, Department of Intensive Care Medicine, Chi Mei Medical Center, No. 901 Zhonghua Rd, Yongkang District, Tainan City 71004, Taiwan (dtmed141@gmail.com).

Published Online: November 18, 2024. doi:10.1001/jama.2024.20747

Conflict of Interest Disclosures: None reported.