Short-term exposure to ambient air pollutants may alter the prothrombotic state and C-reactive protein (CRP) levels in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), according to a study recently published in the journal BMC Pulmonary Medicine.

The investigators sought to explore the how changes in a patient’s coagulation function and CRP levels might be associated with the level particulate matter (PM) in the days preceding the patient’s hospitalization for AECOPD. A retrospective analysis was conducted using medical records of patients with AECOPD admitted to the Putuo Hospital, Shanghai University of Traditional Chinese Medicine in Shanghai, China, between March 2017 and September 2019. Researchers analyzed the association of patients’ PM levels in the days prior to hospitalization with these patients’ changes in prothrombin time (PT) and CRP levels.

Data from a total of 446 patients with AECOPD were collected from medical records and analyzed retrospectively. Following the exclusion of some individuals, 317 eligible patients were included in the final analysis. PM smaller than 2.5 µm in diameter (PM2.5) and PM smaller than 10 µm in diameter (PM10) were measured.


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Results of the study showed that the peripheral blood PT of patients with AECOPD was significantly lower in those with a PM2.5 level of 25 mg/L or more on the day prior to hospitalization vs those with a PM2.5 level of less than 25 mg/L (P =.041). In patients with severe Global Initiative for Chronic Obstructive Lung Disease (GOLD) class who were exposed to less than 25 mg/L of PM2.5 on the day prior to hospital admission, significant differences in PT were observed (P =.008).

Further, peripheral blood CRP levels in patients with AECOPD was significantly higher in those who were exposed to PM2.5 levels of 25 mg/L or more and PM10 levels of 50 mg/L or more on the day prior to hospitalization vs those exposed to PM2.5 levels of less than 25 mg/L and PM10 levels of less than 50 mg/L (P =.046 and P =.009, respectively). Additionally, exposure to less than 25 mg/L of PM2.5 on the day prior to hospital admission was significantly associated with CRP levels (adjusted odds ratio, 1.91; 95% CI, 1.101-3.315; P =.024).

The researchers concluded that when patients with AECOPD are exposed to high PM levels on the day prior to hospitalization, increased CRP levels and shortened PT are observed. PM2.5 levels had a greater impact on CRP level and PT than did PM10 levels. Those with severe GOLD class were shown to be more sensitive to the PM2.5-induced shortening of PT compared with those with other GOLD classes. Additional prospective studies are warranted to confirm these findings.

Reference

Tang L, Shi S, Wang B, et al. Effect of urban air pollution on CRP and coagulation: a study on inpatients with acute exacerbation of chronic obstructive pulmonary disease. BMC Pulm Med. 2021;21(1):296. doi:10.1186/s12890-021-01650-z