Many adults with chronic obstructive pulmonary disease are prescribed opioids to treat pain, breathlessness, insomnia and other complaints. But new research shows those drugs may be further endangering the health of people with the common lung disease.

The new study, published Thursday in the European Respiratory Journal, found COPD patients given an opioid prescription are more likely to visit the emergency room, suffer pneumonia or die within 30 days of starting the drug compared to COPD patients who did not receive opioid painkillers.

Dr. Nicholas Vozoris, lead author of the study and assistant professor in the division of respirology at the University of Toronto, said he has become increasingly concerned over the fact many COPD patients are taking opioids.

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"Physicians and patients need to be a lot more careful and judicious about their use because their use is associated with real and clinically important negative outcomes," said Vozoris, who is also a staff physician at Toronto's St. Michael's Hospital.

COPD is the fourth leading cause of death in Canada and accounts for more hospital admissions than any other chronic disease across the country. The disease, which can be overlooked or misdiagnosed as bronchitis or another infection, is characterized by airway inflammation and narrowing and reduced lung function.

Typically caused by smoking, COPD is irreversible and there are no cures, but there are treatments that can help slow progression, particularly if they are started early.

One important treatment is pulmonary rehabilitation – an educational and support program to help patients learn breathing techniques and other important information – but it is often underfunded or not available in many areas of the country, Vozoris said.

Opioids are commonly used to treat chronic pain, but also come with risks of dependency, addiction and death. More doctors and addiction experts are calling attention to the over-prescribing of opioids as one of the driving factors behind the growing rates of dependency and death tied to the drugs across the country. Canada is the second leading per capita consumer of opioids in the world and Health Minister Jane Philpott recently characterized the problem as a national health crisis.

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While opioids are known to cause respiratory depression, they are often given to COPD patients because those individuals tend to also suffer from chronic pain, insomnia and a host of other conditions as a result of the disease. Vozoris said he treats many COPD patients dealing with breathing problems, and noticed many of them had also been prescribed an opioid. His concern prompted him to study what impact those drugs were having on patients.

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For the study, he and his colleagues looked at health records for people 66 and over living in the community with diagnosed COPD from 2007 to 2012. Of the nearly 131,000 patients identified, 68 per cent had been given a new prescription for an opioid. The researchers followed them for 30 days to see what happened. Those people that hadn't been prescribed an opioid became the study control group.

The researchers found that COPD patients taking opioids were more likely to go to the emergency room, develop pneumonia or die from pneumonia- or COPD-related causes within a month of starting the medication when compared with the control group.

For instance, 1.9 per cent of the patients taking opioids died within 30 days, compared to 1.1 per cent of the control group. A total of 1,294 people, or 1.5 per cent of those taking opioids, were hospitalized for COPD or pneumonia during the follow-up period, compared to 561, or 1.3 per cent, of those in the control group.

Vozoris also pointed out that even those individuals given short-acting opioids at low doses were more likely to be hospitalized for COPD or pneumonia, indicating the drugs are never innocuous.

But it's important to keep in mind the study doesn't prove opioids caused complications and death among COPD patients, said Dr. James Downar, a critical care and palliative care physician at Toronto's University Health Network, who was not involved in the study. Downar points out that opioids are commonly used to treat shortness of breath and other worsening symptoms in people with COPD. So it's plausible that patients who developed pneumonia or died after starting opioids didn't experience those outcomes because of the drugs, but because of a worsening illness. Opioids remain an important treatment option for people with COPD, he said.

However, the researchers did find that disease exacerbations, or flare-ups, were less common among opioid users.

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Vozoris said the findings suggest doctors need to be more careful prescribing opioids to COPD patients.

"Maybe we should be looking at other things before going to narcotics, like pulmonary rehabilitation," he said.