Outcomes of low-dose trimethoprim-sulfamethoxazole treatment in patients with non-HIV pneumocystis pneumonia: A nationwide Japanese retrospective cohort study

Objectives

Low-dose trimethoprim-sulfamethoxazole (TMP-SMX) may be a treatment option for patients with Pneumocystis jirovecii pneumonia (PCP). However, its effectiveness in patients without human immunodeficiency virus (HIV) infection has yet to be thoroughly investigated.

Methods

This retrospective cohort study used data extracted from the Japanese Diagnosis Procedure Combination inpatient database. We included immunocompromised patients without HIV having been diagnosed with PCP and had started TMP-SMX treatment between July 2010 and March 2022. We divided eligible patients into conventional-dose (15.0–20.0 mg/kg/d) and low-dose (7.5–15.0 mg/kg/d) groups and performed propensity-score overlap-weighting analysis. The primary outcome was in-hospital mortality rate. Secondary outcomes were completion of the initial treatment and use of alternatives to TMP-SMX for PCP treatment during hospitalization.

Results

Among 4449 eligible patients, 1682 (37.8 %) and 2767 (62.2 %) received conventional- and low-dose TMP-SMX treatments, respectively. No significant difference was observed in in-hospital mortality (risk difference, −1.4 %; 95 % CI, −4.5–1.7 %; P = 0.388). Low-dose TMP-SMX was associated with increased completion of initial treatment (risk difference, 4.6 %; 95 % CI, 2.3–6.9 %; P < 0.001), and reduced use of alternative agents (risk difference, −4.0 %; 95 % CI, −7.4 to −0.6 %; P = 0.020).

Conclusion

Low-dose TMP-SMX may be a treatment option for patients with non-HIV PCP.