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Study compares medications for COPD

Patients with emphysema or chronic bronchitis had a lower death rate taking one class of COPD medication than another in a five-year study period, Ontario health administrative data reveals.

Patients with emphysema or chronic bronchitis had a lower death rate taking one class of COPD medication than another in a five-year study period, Ontario health administrative data reveals.

Chronic obstructive pulmonary disease, or COPD, affects an estimated 12 to 20 per cent of the adult population, and is the fourth most common cause of death in Canada.

Although it’s a common disease, it doesn’t get the recognition it needs, partly because it’s associated with smoking, said researcher Dr. Andrea Gershon of the Institute for Clinical Evaluative Sciences in Toronto.

However, anywhere from 15 to 50 per cent of sufferers were never smokers, she noted, and other risk factors include occupational exposures and second-hand smoke.

COPD is a huge burden on the health-care system and contributes to long wait times in emergency departments, Gershon said.

Her team examined records of more than 46,000 patients aged 66 years or older who were diagnosed with COPD.

The patients were newly prescribed either an inhaled, long-acting beta-agonist like salmeterol and fomerterol or an anticholinergic like tiotropium between 2003 and 2007. Patients were followed for up to 5 1/2 years to compare survival rates.

The drugs help to widen the various “tubes” that make up the airway so that patients can breathe easier and air can flow better, Gershon said.

“People who were on the beta-agonists had a higher survival than those who were on the anticholinergics, so the people on the long-acting anticholinergics were ... more likely to die sooner than those on the beta-agonists,” Gershon, a respirologist, said in an interview.

She said 39.9 per cent of patients on the long-acting anticholinergic drugs died, compared to 36.5 per cent of those on long-acting beta-agonists. That works out to a decrease in time to death of about three months.

“It was a very modest effect — it wasn’t a huge effect, it was a difference of 14 per cent,” said Gershon, referring to figures after they were adjusted for a number of demographic and clinical factors.

“We think that that’s important because I think any patient would be interested in knowing there is any difference.

“And when you consider all the people on these medications, the difference of 14 per cent (multiplied) over the hundreds of thousands of people who have COPD can really make a huge difference.”

Gershon said the study, published in the Annals of Internal Medicine, is the first head-to-head comparison of the two classes of medication looking at death as the outcome.

But she said the results would need to be confirmed in other studies before they are applied in practice or policy.

Dr. Robert Cowie, a respirologist at the University of Calgary, said it’s useful information but very difficult to interpret.

“There certainly is plausibility to this result. There is this (previous) data that suggests the anticholinergics may play a permissive role, that they might encourage the development of arrhythmias, it’s thought, and through that have cardiac or cerebrovascular complications,” he said.

“But when we look at the clinical trials, at the randomized clinical trials, there really are enormous numbers of people now who’ve been subjected to these drugs under that sort of environment, and they haven’t really shown the signal at all.”

Cowie said he doesn’t think the findings change anything.

“Tiotropium has proved to be a very effective drug, and I think that most people would not stop using it on the basis of this study,” he said.

“More people today, I think, use the long-acting anticholinergic tiotropium than they do the long-acting beta-agonists, and I think that reflects people’s comfort with it — because it’s generally well tolerated, that patients like it, they like the once-a-day therapy,” he said.

Gershon said beta-agonists are taken twice a day.

A drawback of any observational study is potential confounding by indication or by disease severity, the authors wrote.

“Because our data did not contain a precise measure of disease severity (such as lung function), we cannot be sure that such confounding did not occur.

“However, we consider confounding unlikely because we controlled for many prognostically important variables,” they wrote.