Time to trimethoprim/sulfamethoxazole initiation among patients with rheumatic disease complicated by Pneumocystis jirovecii pneumonia: impact on 90-day mortality

Pneumocystis jirovecii pneumonia (PJP) is a life-threatening disease with increasing prevalence in patients with rheumatic disease. Trimethoprim/sulfamethoxazole (TMP/SMX) is an effective treatment for patients with rheumatic disease hospitalized for PJP. This study aimed to describe the 90-day mortality of patients with rheumatic disease complicated by PJP and investigate whether the administration of TMP/SMX after 7 days from initial symptoms correlates with 90-day mortality. We enrolled consecutive patients with rheumatic disease complicated with PJP in our center from August 2018 to August 2021. The participants were classified into two groups according to when TMP/SMX was initiated: early (within the first 7 days) and late (after 7 days). The primary outcome was 90-day PJP-related mortality. Multivariate cox regression and Kaplan-Meier survival analyses were conducted to identify the risk factors for mortality and examine differences in survival between early and late use of TMP/SMX. Thirty-seven patients with rheumatic disease (median age 50.1 years, 24.3% male) complicated by PJP were enrolled in our study, and 15 (40.5%) patients died at or before 90 days of follow-up. The most common comorbidity was systemic lupus erythematosus (14, 37.8%), followed by inflammatory myopathy (11, 27.9%). Patients in the early group were less likely to require mechanical ventilation (8/27, 29.6% vs. 9/10, 90.0%, P = 0.002), lower doses glucocorticoids (43.2 mg/d vs. 72.2 mg/d, P = 0.039) and had lower mortality (7/27, 25.9% vs. 8/10, 80.0%, P = 0.006) than those in the late group. In the Kaplan-Meier analysis, the survivor probability of the early group was notably higher than that of the late group (P = 0.007). Multivariate cox regression analysis showed that initiation of TMP/SMX after 7 days from admission (hazard ratio [HR]: 5.9, 95% confidence interval [CI]: 1.1-30.4; P = 0.034) and a higher level of lactate dehydrogenase (LDH; HR: 6.0, 95% CI: 1.1-31.8; P = 0.035) were associated with 90-day mortality in patients with rheumatic disease complicated by PJP. Patients with rheumatic disease complicated by PJP had poor prognoses, with mortality rates as high as 40.5%. TMP/SMX initiation after 7 days from initial symptoms and a higher level of serum LDH were significantly associated with increased 90-day mortality.