Pseudomonas aeruginosa (PA) can play an important role in the course of chronic obstructive pulmonary disease (COPD) in patients who have frequent hospitalizations because of exacerbations (FHE) of the disease, according to study results published in Respiration.
COPD exacerbations that necessitate hospitalization are associated with poor outcomes and account for the majority of costs associated with the disease. Patients hospitalized with an exacerbation have an increased risk for future hospital admissions as well as an increased risk for death.
Ana Rodrigo-Troyano, MD, of the Department of Respiratory at Hospital de la Santa Creu I Sant Pau, Autonomous University of Barcelona Medicine Department and Biomedical Research Institute Sant Pau in Barcelona, Spain, and colleagues conducted a prospective observational multicenter study to determine prevalence, risk factors, susceptibility patterns and effect on outcomes of PA in people with COPD and FHE.
Investigators enrolled 207 patients with COPD and FHE and collected a sputum culture from 119 patients (57%). Twenty-one patients (18%) were found to harbor PA. Prior use of systemic corticosteroids (odds ratio [OR], 3.38; 95% CI, 1.2-91; P =.01) and prior isolation of PA (OR, 4.36; 95% CI, 1.4-13.4; P <.01) were risk factors associated with the presence of PA. Patients who had PA were at increased risk of having had ≥3 hospital readmission (OR, 4.1; 95% CI, 1.3-12.8; P =.01) and a higher isolation rate of PA (OR, 7.7; 95% CI, 2.4-24.6; P <.001) during the follow-up period.
Antibiotic resistance was common, with 67% of patients carrying a PA strain that was resistant to ≥1 of the antibiotics tested. Persistence in the airways following appropriate antibiotic therapy was also common. PA persisted in the sputum of 70% of patients who had been treated appropriately for the pathogen.
The study had several limitations, including that only 57% of patients had a good quality sputum culture on admission. Another limitation was the preponderance of men in the cohort of patients (83%). Furthermore, the isolation of PA in sputum can represent the colonization of upper airways or infection of lower airways. Finally, sputum samples were collected at the discretion of the physician.
The researchers noted that although the data show that PA has an important role in the course of COPD in patients with FHE, the 1-year mortality did not differ between those patients with and those without PA.
Rodrigo-Troyano A, Melo V, Marcos PJ, et al. Pseudomonas aeruginosa in chronic obstructive pulmonary disease patients with frequent hospitalized exacerbations: a prospective multicentre study [published online July 24, 2018]. Respiration. doi:10.1159/000490190