Evaluating the Emergency Department admission and hospitalization trend for COPD Exacerbation and time-dependent Particulate Matter exposure

Purpose
We evaluated the relationship between short-term exposure to PM10 – PM2.5 and COPD Exacerbation, in terms of Emergency Department (ED) admissions and their outcomes in Brescia, one of the most polluted European cities.
Methods
ED admission data from 431 patients with diagnosis of COPD Exacerbation were collected, starting from January 2014 to January 2016. Daily PM levels were collected from the Environmental Protection Regional Agency (ARPA). A time-series study, using the Poisson regression model with single and multiple day-lag, has been performed. Results were expressed as Relative Risk (RR) and Excess of Relative Risk (ER) for COPD Exacerbation-related ED admissions and hospitalizations, over a 10µg/m3 increase in PM concentration.
Results
Both PM10 and PM2.5 were significantly associated with the risk of COPD exacerbation-related ED admission and hospitalization. Each increase of 10µg/m3 of PM10 and PM2.5 corresponded respectively to a RR(CI95%) for ED admissions of 1.06 and 1.08 in lag0-1; 1.06 and 1.09 in lag0-5 (p<0.05). Similar results for COPD Exacerbation-related hospitalizations have been found, with a RR of 1.07 and 1.10 in lag0-1; 1.07 and 1.11 in lag0-5.
Conclusions
Our findings show that an increasing exposure to PM10-PM2.5 is associated to higher ED admission and increasing hospitalizations due to COPD exacerbation.
Clinical Implications
Short-term exposure to elevated Particulate Matter (PM) concentrations can cause a worsening of several respiratory conditions.