Impact of Antipseudomonal Antibiotics in Patients with Bronchiectasis Who Experienced Exacerbation or Developed Pneumonia: A Nationwide Study in Japan

Background/Objectives: Although chronic infection by Pseudomonas aeruginosa among patients with bronchiectasis is associated with poor prognosis, the impact of antibiotics with P. aeruginosa coverage in patients with bronchiectasis who experienced bacterial pneumonia or exacerbation of bronchiectasis has not been fully investigated. Methods: This study targeted patients with bronchiectasis who were admitted to hospitals because of bacterial pneumonia or exacerbation of bronchiectasis between April 2018 and March 2020 using a national inpatient database in Japan. The association of antipseudomonal antibiotic treatment with in-hospital mortality was assessed after propensity score matching to adjust the patients' backgrounds. Results: In total, 4943 patients with bacterial pneumonia and 1914 patients with exacerbation of bronchiectasis were included in this study. The in-hospital mortality rate did not differ between patients who did and did not receive antipseudomonal agents among patients with bacterial pneumonia (9.0% [185/2045] vs. 7.4% [151/2045]; p = 0.053) and those with exacerbation of bronchiectasis (5.2% [42/803] vs. 4.1% [33/803] group; p = 0.287). Conclusions: The use of antibiotics covering P. aeruginosa does not apparently improve prognosis in patients with bacterial pneumonia or exacerbation of bronchiectasis. A prospective study focusing on the impact of antibiotics covering P. aeruginosa among patients with bronchiectasis in whom P. aeruginosa is isolated is required.