Patterns and Predictors of Air Cleaner Adherence Among Adults with COPD

Rationale: Poor indoor air quality has been associated with worse chronic obstructive pulmonary disease (COPD) morbidity. In-home portable air cleaners reduce indoor pollutants and could improve respiratory health. Factors associated with air cleaner adherence among adults with COPD remains unknown. Methods: In a 6-month trial of former smokers with COPD, participants (n=116) received active or sham portable air cleaners. Air cleaner adherence was measured by electronic monitors. Potential baseline predictors of adherence included individual factors (demographics, socioeconomic status, smoking history, psychological well-being), COPD disease severity, and housing characteristics. Time and season were also considered. Stepwise logistic regression and longitudinal fixed effect analysis were performed to assess independent predictors of adherence. Results: A total of 109 participants had an objective measure of adherence, and 76.1% used at least 1 air cleaner 80% of the time (defined a priori as adherent). Higher annual household income ≥$35,000 (odds ratio [OR]=4.4, 95% confidence interval [CI], 1.1-18.0) and use of heat pump/electricity (versus gas) for heating (OR=6.1, 95%CI, 1.7-22.4) were associated with higher odds of adherence. Further, poor quality of life (St George's Respiratory Questionnaire, per 10-point increase) and prior year exacerbations were associated with lower odds of adherence (OR=0.65, 95%CI, 0.4-1.0) and (OR=0.26, 95%CI, 0.1-0.9), respectively. Adherence was highest during the first month and lower during winter compared to other seasons. Conclusion: These findings suggest that cold weather season, use of gas for home heating, and lower annual income negatively impact adherence. Poor quality of life and worse disease control may also decrease adherence. Addressing factors associated with air cleaner adherence should be considered when designing future environmental studies.