In the BLOCK COPD (Beta-Blockers for the Prevention of Acute Exacerbations of Chronic Obstructive Pulmonary Disease) trial, the authors wanted to determine whether the administration of a beta-blocker metoprolol in patients with COPD, characterized by increased rate of exacerbations, would lower the risk of exacerbations without having an adverse effect on lung function, exercise capacity, symptoms and quality of life.
532 patients underwent randomization. Patients were moderate to severe airflow limited, had an increased rate of exacerbations, mainly treated with triple therapy and had no established indication for the use of such drugs.The primary end point was the time until the first exacerbation of COPD during the treatment period which was approximately 1 year.
The study stopped earlier due to futility with respect to the primary endpoint and safety concerns. Based on the results the study was negative. There was no significant between-group difference in the median time until the first exacerbation, which was 202 days in the metoprolol group and 222 days in the placebo group. Patients treated with metoprolol had more hospitalizations compared to those treated with placebo. Adverse events were not significantly differed between the two groups. The metoprolol arm had 11 deaths while the placebo 5. Hospitalization for exacerbation was more common among the patients treated with metoprolol.
The main conclusion that derived from the above study was the following: Among patients with moderate or severe COPD who did not have an established indication for beta-blocker use, the administration of metoprolol failed to show any significant benefit in time to first exacerbation.
COPD and cardiac diseases share recognized risk factors, while concomitant chronic cardiovascular disorders are frequent in patients with COPD.The main indications of beta blockers are heart failure and MI. Data mainly derived form meta-analysis clearly supports that the use of beta blockers in COPD may alter both mortality and the rate of exacerbations. However, the current study clearly showed that in absence of the above indications no significant benefits were observed. So, which is the main clinical message? In the absence of a clear indication do not use beta blockers in COPD.
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