Introduction Particulate matter 2.5 (PM_2.5) adversely affects COPD outcomes. Efficacy of individual-level interventions to reduce PM_2.5 exposure is not well known.

Aims and objectives We investigated if lifestyle interventions to reduce PM_2.5 exposure improve clinical outcomes in patients with COPD.

Methods COPD patients aged 40-80 years with FEV₁ %predicted <80% were included in this multicenter randomized controlled trial. Study participants were 1:1 randomized to either the intervention or control group and followed for 9 months. The intervention comprised 5 activities: air quality forecast check; indoor air cleaner use; regular home ventilation by opening windows; adherence to inhaler therapy; and avoidance of going out on heavy pollution days. The outcomes were changes in St. George?s Respiratory Questionnaire for COPD patients (SGRQ-C) and COPD assessment test (CAT) scores.

Results A total of 120 patients were randomized, and 102 patients (85.0%) completed the study (51 in each group). The mean age was 67.8 years and 93.1% were men. At the end of the study, the intervention group showed greater reduction from the baseline in the scores of total SGRQ-C (-3.4 vs. 2.5; p=0.049), symptom domain of the SGRQ-C (-9.7 vs. -2.9; p=0.034), and CAT (-1.2 vs. 2.7; p = 0.001) than the control group (Figure 1).

Conclusions Lifestyle interventions to avoid PM_2.5 significantly improved the quality of life and symptoms in patients with COPD.