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Background: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. Air pollution is associated with a decrease in lung function and an increase in inflammatory biomarkers, respiratory symptoms, and hospital admissions due to several causes, including COPD exacerbations. Nevertheless, uncertainty exists on whether indoor air quality improvement could lead to a reduction in morbidity associated with COPD. Therefore, we aim to prove the efficacy of High-Efficiency Particulate Air (HEPA) filters to reduce respiratory symptoms related to COPD exacerbations.
Methods: We propose a single-center, parallel, controlled, randomized with a 1:1 allocation, double-blinded, phase III trial that will be performed on patients 45 years and older with moderate to severe COPD in Mexico city, comparing the use of HEPA filters with carbon air filters vs. sham devices. The main outcome will be the average change of the COPD Assessment Test (CAT) score between baseline and 4-month follow-up comparing intervention and control groups. Secondary outcomes will include CAT score measurements at 8 and 12 months, distance measured by a 6-minute walk test, Forced Expiratory Volume in 1 second, and number of and time to exacerbations measured at 4, 8, and 12 months.
Discussion: With this intervention, we expect to reduce symptoms associated with COPD, therefore observing a reduction in emergency department visits, hospital admissions, and economic burden. The results of this study could potentially help assess future guidelines, economic analysis, and healthcare policies on the implementation of air cleaning strategies and healthcare policies, directing resources towards air quality improvement.
Keywords: Chronic Obstructive Pulmonary Disease, Air Filters, Pollution, Exacerbations, Randomized Clinical Trial, COPD Assessment Test.