Frequency of Exacerbations of Chronic Obstructive Pulmonary Disease Associated with the Long-Term Exposure to Air Pollution in the AIREPOC Cohort.

Background: Exacerbations of chronic obstructive pulmonary disease (COPD-E) have been associated with levels of air pollution. The occurrence of COPD-E is associated with increased mortality in this population.

Purpose: To determine the association between long-term exposure to PM_2.5 and NO₂, and the frequency of COPD-E in patients belonging to AIREPOC, an institutional integrated care program for COPD in Bogota, Colombia.

Patients and methods: Retrospective cohort study included patients with COPD living in Bogotá, between 2018 and 2021, who received health care in the AIREPOC program. Each patient´s home address was geolocated. Information from local air quality network stations was used to estimate daily and annual mean PM_2.5 and NO₂ exposure level for each patient using the inverse distance squared weighted regression (IDWR) method. The effect of PM_2.5 and NO₂ concentrations categorized at 15 µg/m³ and 25 µg/m³ respectively on the frequency of COPD-E was estimated using a zero-truncated negative binomial model adjusted for potential confounders. Goodness-of-fit was assessed by residuals.

Results: During the observation period, 580 COPD-E occurred in 722 patients. Significant associations were found between COPD-E and NO₂ concentrations ≥25 µg/m³ (incidence density ratio, RDI: 1.29, 95% CI: 1.02-1.67) after adjustment for sun exposure, COPD severity, depression, and ambient humidity. No association was found between the frequency of COPD-E and PM_2.5 concentrations ≥15µg/m³.

Conclusion: Prolonged exposure to high levels of NO₂ increases the frequency of COPD exacerbations in patients residing in Bogotá. These results highlight the importance of strengthening air quality control measures and educating people with COPD to know and interpret the local air quality indices and to follow the recommendations derived from its alterations.