Beta-blockers linked to COPD benefits

[kkmalaysia]

New research suggests that beta-blockers may benefit people with chronic obstructive pulmonary disease (COPD) by reducing symptom severity and improving survival.

While COPD patients are prone to developing cardiovascular diseases and beta-blockers have been proven to reduce cardiovascular mortality by reducing risk factors such as hypertension, physicians have traditionally shunned these agents in patients with COPD. This is due to a perception that beta-blockers have bronchoconstrictive properties and that they compete with the beta-2-agonists often prescribed to COPD patients.

Now an observational cohort study has suggested that beta-blockers are not harmful to patients with COPD, and they may even be beneficial.

The study, led by Dr. Frans H. Rutten, of the Julius Centre for Health Sciences and Primary Care at University Medical Centre Utrecht, the Netherlands, examined data from the electronic medical records of 23 general practices in the Netherlands. It included 2,230 patients aged 45 years and above with an incident or prevalent diagnosis of COPD between 1996 and 2006. The mean age of the cohort was 64.8 and 53 percent were males.

Over more than 7 years of follow-up, 686 patients died. Only 27.2 percent of patients taking a beta-blocker died, compared to 32.3 percent of those not taking a beta-blocker (P=0.02). In terms of COPD exacerbations, 42.7 percent of patients taking a beta-blocker had at least one exacerbation over the follow-up period, compared to 49.3 percent of those not taking a beta-blocker (P=0.005). [Arch
Intern Med 2010;170(10):880-887]

“Our study is in line with the other recent ones showing that beta-blockers seem to be well-tolerated in COPD. This means that whenever a patient has an indication for beta-blockers like hypertension, ischemic heart disease, atrial fibrillation, heart failure and peri-operatively for vascular surgery, beta-blockers should be administered and are in general, well-tolerated,” said Rutten.

“A randomized controlled trial (RCT) is needed to confirm whether beta-blockers have a beneficial effect on the lungs independent of their effect on hypertension and (non-overt) cardiovascular disease. In our observational study, bias by indication is still possible, but the beneficial effect of beta-blockers on exacerbations is intriguing.”

In an accompanying editorial, Dr. Don Sin and Dr. S.F. Paul Man of the Department of Medicine at the University of British Columbia in Vancouver, Canada said, “the study by Rutten et al. provocatively suggests that the use of beta-blockers, contrary to classic teaching, is not only safe but also can prolong survival and reduce exacerbations in COPD, providing new hope for patients with COPD.” However, they did agree with the study authors on the need for a large well-conducted RCT to confirm their findings.

But Rutten said RCTs on beta-blockers face major financial hurdles.

“A major problem is that over 2,000 patients should be included when mortality is the major endpoint and thus, [several] million dollars are needed to execute such a trial,” he said. “Moreover, almost all beta-blockers are off-patent now, so the pharmaceutical industry is not very likely to be interested in such a trial.”

Some doctors called the study a “surprising turn of events” in this long-running issue and expressed caution.

“The story of beta-blockers in COPD turning from a foe to a potential friend should be borne out by well-designed prospective clinical trials because this issue is huge, potentially affecting a large number of patients,” said Dr. Ong Kian Chung, president of the COPD Association in Singapore, noting that an estimated 64,000 persons are affected by COPD in Singapore alone.

“Thus, to abandon our long-standing belief based on one retrospective study may prove to be unwise.”

Ong highlighted several limitations of the Rutten et al. study as well, including possible misclassification of COPD, possible confounding by indication, lack of spirometry in all patients, and possible residual confounding.

Source: mims.com