Can air filters improve COPD symptoms?

COPD guidelines address many aspects of patient care, including smoking cessation, medication use, and supplemental oxygen. But they don’t address the idea of using air filters to help patients breathe better.

Can we improve COPD symptoms, and prevent exacerbations, just by using an air filter in the patient’s home? This study asks that question.

Researchers recently studied the use of HEPA air filters placed in the homes of people with moderate or severe chronic obstructive pulmonary disease. 116 patients were randomized, receiving either a HEPA air filter or a sham air filter in their home. 31% of people enrolled had low particulate matter counts, and they were excluded. Everyone was followed up for 6 months.

The primary outcome was changes in scores on the St. George’s Respiratory Questionnaire. Secondary outcomes included scoring subsets on the questionnaire as well as exacerbations.

The results do get a little complicated depending on if you look at per-protocol analysis or intention-to-treat. For the patients who used the filter at least 80% of the time, symptoms improved and there were far fewer moderate exacerbations. Both of those differences were statistically significant. We cover this study and many more at our next continuing medical education conference.

Granted, this was a small study, but it was randomized, and even utilized a placebo sham air filter. And it’s hard to imagine any real risk with placing an air filter in someone’s home, especially if they have a high particulate matter in their indoor air. As well, this should not be expensive, especially when one considers how expensive COPD medications are, and the costs associated with exacerbations.

Does this mean we should now be recommending HEPA filters to patients with COPD? And when one thinks about the atopic components of asthma, it seems we might see even more robust results in that patient population.

Reference: Hansel et al. Randomized Clinical Trial of Air Cleaners to Improve Indoor Air Quality and Chronic Obstructive Pulmonary Disease Health: Results of the CLEAN AIR study. Am J Respir Crit Care Med 2022;205:421

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