Harmful impact of air pollution on severe acute exacerbation of chronic obstructive pulmonary disease: particulate matter is hazardous

Abstract

Introduction: Particulate matter and air pollution in Korea are becoming worse. There is a lack of research regarding the impact of particulate matter on patients with COPD. Therefore, the purpose of this study was to investigate the effects of various air pollution factors, including particulate matter, on the incidence rate of severe acute exacerbations of COPD (AECOPD) events.

Methods: We analyzed the relationship between air pollutants and AECOPD events that required hospitalization at Guro Hospital in Korea from January 1, 2015 to May 31, 2017. We used general linear models with Poisson distribution and log-transformation to obtain adjusted relative risk (RR). We conducted further analysis through the Comprehensive Air-quality Index (CAI) that is used in Korea.

Results: Among various other air pollutants, particulate matter was identified as a major source of air pollution in Korea. When the CAI score was over 50, the incidence rate of severe AECOPD events was statistically significantly higher [RR 1.612, 95% CI, 1.065-2.440, P=0.024]. Additionally, the particulate matter levels 3 days before hospitalization were statistically significant [RR 1.003, 95% CI, 1.001-1.005, P=0.006].

Conclusion: Particulate matter and air pollution increase the incidence rate of severe AECOPD events. COPD patients should be cautioned against outdoor activities when particulate matter levels are high.

Keywords: COPD; acute exacerbation; air pollution; air quality index; particulate matter.

Figure 1

Monthly average data related to air pollutants and number of inpatients per day. (A) Monthly average CAI, PM₁₀, and PM_2.5. (B) Monthly average humidity and temperature. (C) Monthly average number of inpatients (patients admitted to hospital for AECOPD) per day. Notes: The average from January to May is from 2015 to 2017; the average from June to December is from 2015 to 2016. Abbreviations: CAI, Comprehensive Air-quality Index; PM₁₀, particulate matter with a diameter of less than 10 µm; PM_2.5, particulate matter with a diameter of less than 2.5 µm.

Figure 2

Association of PM₁₀, CAI and severe AECOPD events after adjustment for humidity and temperature. (A) The association of PM₁₀ and severe AECOPD events. (B) The association of CAI and severe AECOPD events. Abbreviations: PM₁₀, particulate matter with a diameter of less than 10 µm; CAI, Comprehensive Air-quality Index; AECOPD, acute exacerbations of chronic obstructive pulmonary disease.