A Four-Center Retrospective Study of the Efficacy and Toxicity of Low-Dose Trimethoprim-Sulfamethoxazole for the Treatment of Pneumocystis Pneumonia in Patients without HIV Infection

Abstract

The dose of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of <i>Pneumocystis</i> pneumonia (PCP) in patients without human immunodeficiency virus (HIV) infection has not been verified. The aim of this study was to investigate the efficacy and toxicity of a low-dose TMP-SMX regimen in such patients. A retrospective study was conducted in four hospitals. We reviewed the medical records of patients with PCP but not HIV (non-HIV-PCP) who were treated with TMP-SMX between 2003 and 2016. The patients were divided into conventional-dose (TMP, 15 to 20 mg/kg/day) and low-dose (TMP, <15 mg/kg/day) groups after patients who received high-dose (TMP, >20 mg/kg/day) treatment were excluded. Grouping was done according to a correction dose, which was based on renal function. Eighty-two patients had non-HIV-PCP. The numbers of patients who received high-, conventional-, and low-dose treatments were 5, 36, and 41, respectively. Kaplan-Meier analysis for death associated with PCP showed no statistically significant difference in survival rates between the conventional- and low-dose groups. Ninety-day cause-specific mortality rates were 25.0% and 19.5% in the conventional-dose and low-dose groups (<i>P</i> = 0.76), respectively. Adverse events that were graded as ≥3 according to the Common Terminology Criteria for Adverse Events (version 4.0) (National Cancer Institute, 2010) were 41.7% and 17.1% in the conventional-dose and low-dose groups (<i>P</i> = 0.02), respectively. Moreover, vomiting (<i>P</i> = 0.03) and a decrease in platelet count (<i>P</i> = 0.03) occurred more frequently in the conventional-dose group. Treatment of non-HIV-PCP with low-dose or conventional-dose TMP-SMX produces comparable survival rates; however, the low-dose regimen is better tolerated and associated with fewer adverse effects.