Trimethoprim-sulfamethoxazole combined with echinocandins versus trimethoprim-sulfamethoxazole alone for Pneumocystis pneumonia in patients without human immunodeficiency virus infection: A nationwide retrospective cohort study

Background: Although combination therapy of echinocandins with trimethoprim-sulfamethoxazole (TMP-SMX) has been reported for patients with Pneumocystis jirovecii pneumonia (PCP), the effectiveness of this combination therapy in patients with PCP without human immunodeficiency virus (HIV) infection remains unknown. Methods: Data from the Japanese Diagnosis Procedure Combination inpatient database was used to identify non- HIV patients who underwent their first hospitalisation for PCP between April 2012 and March 2022. The patients were divided into those treated with TMP-SMX alone and those treated with TMP-SMX combined with echinocandins. We performed propensity-score overlap-weighting analysis to estimate in-hospital mortality. Results: Among the 1324 eligible patients, 122 received TMP-SMX plus echinocandins, while 1202 received TMPSMX alone. The propensity-score overlap-weighting analysis showed that the combination therapy was not associated with reduced in-hospital mortality in comparison with TMP-SMX alone (22.2 % vs. 26.9 %; risk difference, 4.6 %; 95 % confidence interval,-6.1 %-15.3 %; P = 0.398). Conclusions: Echinocandins combined with TMP-SMX may not improve in-hospital mortality due to PCP in patients without HIV infection.