Randomized Clinical Trial of Air Cleaners to Improve Indoor Air Quality and COPD Health: Results of the CLEAN AIR STUDY

Background: Indoor particulate matter is associated with worse outcomes in adults with COPD. It remains unknown whether reductions of indoor pollutants can improve respiratory morbidity. Methods: Eligible former smokers with moderate-severe COPD received active or sham portable HEPA air cleaners and were followed for 6 months in this blinded randomized controlled trial. The primary outcome was 6-month change in Saint George’s Respiratory Questionnaire (SGRQ) . Secondary outcomes were exacerbation risk, respiratory symptoms, rescue medication use and 6MWD. Intention to treat analysis included all subjects and per protocol analysis included adherent participants (greater than 80% use of air cleaner). Findings: 116 participants were randomized of which 84.5% completed study. There was no statistically significant difference in improvement of total SGRQ, but the active filter group had greater reduction in SGRQ symptom subscale (s -7.7 [95% CI, -15.0 to -0.37]) and respiratory symptoms (BCSS, s -0.8 [95% CI, -1.5 to -0.1); and lower risk of moderate exacerbations (IRR 0.32 [95% CI, 0.12-0.91]) and rescue medication use (IRR 0.54 [95% CI, 0.33-0.86]) compared to sham group (all p