This study evaluates the influence of home air purification on the lung health of adults with eosinophilic COPD. Half of the participants will receive real air purifiers (HEPA filters) and half will receive sham air purifiers.

Chronic obstructive pulmonary disease (COPD) is the third most common cause of death in the United States, and is exacerbated by exposure to air pollution. Knowledge about whether air purification affects the health of those with eosinophilic COPD (approximately 40% of all COPD patients seeking care), who generally have more active airway inflammation. If found to be beneficial, home air purification may offer a non-pharmacologic intervention for a large proportion of people with this common and serious disease.

This study will evaluate whether home air purification affects lung function, respiratory symptoms, nasal biomarkers (inflammatory proteins and metals) among people with eosinophilic COPD. Participants will be randomized to receive real or sham air purifier in the bedroom and living room for 12 months. The intervention group will receive two high efficiency particulate air (HEPA) air purifiers, while the control group will receive two sham air purifiers that look and sound the same as real HEPA air purifiers.

Inclusion Criteria:

• Age of 40 years or more
• Physician diagnosis of COPD [Global Initiative for Obstructive Lung Disease (GOLD) Stage II-IV disease with Forced Expiratory Volume (FEV1)/ Forced Vital Capacity (FVC) ≤70% and FEV1 (% predicted) <80%]
• Blood eosinophil count of >=150 cells per μL at screening or in the previous year
• Former smoker with tobacco exposure of >=10 pack-years

Exclusion Criteria:

• Inability to complete monthly questionnaires
• Inability to perform lung function testing
• Regularly using a portable HEPA air purifier in the home at time of enrollment
• End stage chronic disease with life expectancy <2 years as determined by PI judgment
• Living in location other than home (e.g. long term care facility)
• Planning to change residence within the study period

After study completion, data requests for post-hoc analyses may be submitted to the PI who will discuss each request with members of the research team and External Advisory Committee. If approved, we will facilitate secure access to data with appropriate coding files that will allow interpretation of the dataset. We will utilize data-sharing agreements to restrict the transfer of data, requiring that data be used only for research purposes. If excessive data preparation is needed, we will request funds from the requester to cover the additional personnel and resource costs.

After study completion, requests for data sharing will be addressed within 3 months.

Data requests must be accompanied by a data analysis plan, which includes the scientific background and rationale for the proposed analysis, variables needed, analytical approach, and qualifications of the research team. Investigators must be able to demonstrate they have the skills and resources to analyze the data and protect the data in a secure environment.

Sham air purifiers will be indistinguishable from real air purifiers. Only the research assistant installing the purifiers and the data coordinating center will have knowledge of assignment to real or sham purifiers.