The role of trimethoprim/sulfametoxazole in reducing relapses and risk of infections in ANCA-associated vasculitis: a meta-analysis

Objectives. To assess available evidence from randomized controlled trials (RCTs) and observational studies including a control group regarding the role of trimethoprim/sulfametoxazole (TMP/SMX) in reducing the relapse rate in patients with granulomatosis with polyangiitis (GPA) and the risk of infections in patients with ANCA-associated vasculitis (AAV). Methods. MEDLINE, EMBASE, The Cochrane Library databases, Scopus, Web of Science and ClinicalTrials.gov were searched from inception until 15 January 2020 to identify controlled studies assessing the role of TMP/SMX in reducing the rate of relapse in patients with GPA (primary outcome) and the number and/or severity of infections in patients with AAV (secondary outcome). Two reviewers independently selected eligible studies and extracted data. Cumulative risk ratios (RRs) with 95% CI were calculated using a random effect meta-analysis. Results. Eight studies were selected out of 2907 records. Seven studies (520 patients) (of which two were RCTs) assessed the role of TMP/SMX in the relapse rate in patients with GPA. TMP/SMX was not associated with a reduced risk of relapse (RR=1.15, 95% CI: 0.51, 2.55; I-2 =78.5%; P< 0.001). Sensitivity analysis according to the dose of TMP/SMX (960 mg twice daily vs three times/week) confirmed the results. One retrospective cohort study (192 patients) was identified demonstrating a significant reduction of severe infections in patients with AAV receiving prophylaxis with TMP/SMX in association with rituximab. Conclusion. TMP/SMX was not associated with a reduced risk of relapse in patients with GPA. TMP/SMX might be useful in the reduction of infectious complications.