Updated

There is "compelling evidence" that popular cholesterol-lowering drugs called statins have benefits in people who suffer from chronic obstructive pulmonary disease, more commonly known as COPD.

However, the evidence is not yet strong enough to expand statin indications beyond lowering cholesterol, Canadian researchers caution in a report in the journal Chest.

COPD is a progressive lung disease that makes it hard to breathe. Cigarette smoking is the leading cause of COPD — most people who have COPD smoke or used to smoke, but it is also associated with long-term exposure to other lung irritants, such as air pollution and chemical fumes. The two main components of COPD are emphysema and chronic obstructive bronchitis, which both damage the walls of the lung.

In addition to a proven role in lowering high cholesterol levels, statins also have anti-inflammatory and immune-modulating effects postulated to be beneficial in COPD, Dr. John Swiston, from the University of British Columbia, Vancouver, and colleagues note in their report.

In a systematic review, Swiston's team analyzed nine studies that evaluated the effect of statins in people with COPD.

Individually and collectively, the studies showed that statins have a number of benefits in COPD; they seem to improve lung function and curb COPD flare-ups and COPD-related hospital admissions. They may even cut deaths due to COPD.

The researchers emphasize, however, that data from randomized controlled trials - the gold-standard - are lacking and therefore the current evidence is not enough to support a change in clinical practice that would recommend statins for COPD patients.

"Multiple observational studies in the setting of biological plausibility paints a compelling picture but is not sufficient to justify routine clinical use of statins for COPD patients," Swiston noted in an email to Reuters Health.

"However, the current literature is sufficient to ethically and financially justify large, well designed randomized controlled prospective studies. These types of studies, if properly carried out, will provide stronger evidence either supporting or refuting the utility of statins as part of medical therapy for COPD," Swiston added.