ICS dose may be risk factor for P. aeruginosa infection in severe COPD

Higher inhaled corticosteroid dose may be a risk factor for Pseudomonas aeruginosa infection in patients with severe COPD, according to data published in BMJ Open Respiratory Research.

“The relationship between inhaled corticosteroid use and the risk of Pseudomonas aeruginosa infection and its clinical consequences in patients with COPD are not well established and could modify the indication of this treatment in patients with COPD with frequent exacerbations caused by P. aeruginosa,” Hanaa Shafiek, MD, associate professor in the department of chest diseases at Alexandria University, Egypt, and the department of respiratory medicine at the University Hospital Son Espases, Palma de Mallorca, Spain, and colleagues wrote.

The case-control study enrolled 358 patients with severe COPD (mean age, 73 years; 78% men) following hospitalization for COPD exacerbation from 2012 to 2020. Patients with isolation of P. aeruginosa in sputum during admission or follow-up were compared with patients with other or no potential pathogenic bacteria.

Researchers evaluated clinical and functional characteristics, inhaled corticosteroid (ICS) use and survival.

During a median follow-up of 4 years, 48.3% of patients presented with at least one positive P. aeruginosa culture.

Patients with COPD and P. aeruginosa infection had more frequent exacerbations (6.62 vs. 4.08; P < .001), lower percent predicted FEV₁ (41.34 vs. 45.2; P = .036) and higher mortality (120 vs. 86; P < .001) compared with patients with COPD and no P. aeruginosa infection.

The researchers found no differences in ICS use between the two groups, but ICS dose was higher among patients with COPD and P. aeruginosa (500 µg per day vs. 400 µg per day; P = .007) compared with patients with COPD and no P. aeruginosa infection.

In addition, blood eosinophil count was not different between patients who used ICS and those who did not. ICS dose was an independent risk factor for P. aeruginosa infection and mortality in the multivariate analysis; however, ICS use was not (HR = 1.33; 95% CI, 1.07-1.65; P = .01).

According to the researchers, further research is required to assess the relationship between ICS and P. aeruginosa infection in patients with COPD.

“Our data could reinforce the concept that, by itself, the use of ICS in COPD with frequent exacerbations are of benefit regardless the infectious etiology based on the improvement of their survival,” the researchers wrote. “In addition, our data discourage the use of high doses of ICS in COPD with frequent exacerbations, since it was directly linked to increased risk of P. aeruginosa infection and mortality.”