Trimethoprim/sulfametoxazole (TMP/SMX) may reduce the risk for infectious complications in patients with antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV); however, TMP/SMX may not be associated with a reduced risk for relapse in patients with granulomatosis with polyangiitis (GPA), according to study results published in Rheumatology.

As limited data are available on the role of TMP/SMX in patients with AAV, the objective of the current study was to determine the effect of treatment on the relapse rate in patients with GPA and the risk for infections in patients with AAV.

Researchers conducted a systematic literature review using MEDLINE, Embase, the Cochrane Library databases, Scopus, Web of Science, and from study inception to January 15, 2020. They identified 2 randomized controlled trials, 4 controlled prospective cohort studies, and 1 retrospective cohort study that met the inclusion criteria. The analysis included a total of 520 participants.

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The primary outcome of the analysis was the effect of TMP/SMX on relapse rate in patients with GPA. The secondary outcome was the number and/or severity of infections in patients with AAV.

The meta-analysis, which included data from randomized and nonrandomized studies, showed that treatment with TMP/SMX was not associated with a reduced risk for relapse in patients with GPA (risk ratio, 1.15; 95% CI, 0.51-2.55; I2=78.5%; P <.001).

TMX/SMP had no effect on the risk for disease relapse when prescribed at the full dose (960 mg twice daily) or at a reduced (prophylactic) dose (960 mg thrice a week).

A single retrospective cohort study with 192 patients with AAV indicated that TMP/SMX prophylaxis vs placebo was associated with a 70% lower risk for serious infections (relative risk, 0.30; 95% CI, 0.13-0.69).

The study had several limitations, including a high risk for bias, use of different doses of TMP/SMX, inclusion of observational studies and their inherent limitations, and limited data on the role of TMP/SMX against serious infections.

“TMP/SMX has a role as prophylaxis against [Pneumocystis jirovecii pneumonia] and serious infections, but evidence specifically conducted on patients with AAV was scarce. Further high-quality evidence is warranted to clarify the role of TMP/SMX in the management of AAV,” the researchers concluded.


Monti S, Delvino P, Riboli M, et al. The role of trimethoprim/sulfametoxazole in reducing relapses and risk of infections in ANCA-associated vasculitis: a meta-analysis. Rheumatology (Oxford). Published online March 22, 2021. doi:10.1093/rheumatology/keab267