Bactrim Efficacy in Preventing Infections in Glomerular Diseases Receiving Rituximab

Rationale & Objective The efficacy of combination sulfamethoxazole and trimethoprim (Bactrim) prophylaxis for infection prevention in kidney disease with rituximab therapy remains unclear. This study investigated its effectiveness in 2 distinct glomerular disease groups treated with rituximab. Study Design Retrospective cohort study. Setting & Participants Adults with antineutrophil cytoplasmic antibody-associated vasculitis renal involvement (AAV-R) or renal-limited diseases including membranous nephropathy (MN), minimal change disease (MCD), or primary focal segmental glomerulosclerosis (FSGS) who underwent rituximab therapy between 2012 and 2022 at Mayo Clinic. Exposures Receiving Bactrim or not. Outcomes Severe infection during 1-year follow-up after rituximab initiation. Analytical Approach Kaplan-Meier method used for the probability of survival free of infection. Cox proportional hazards models used for the association between Bactrim use and risk of infection. Results Among 419 patients, 248 were diagnosed with AAV-R and 171 with MN/MCD/FSGS. During the initial rituximab therapy session, 186 (75%) patients with AAV-R and 76 (44%) with MN/MCD/FSGS were concurrently administered Bactrim. Among those with AAV-R, patients prescribed Bactrim versus without Bactrim were generally younger, with lower serum creatinine, elevated white blood cells and neutrophils, and higher steroid use ( P < 0.05 for all). Among patients with MN/MCD/FSGS, those receiving Bactrim exhibited lower albumin levels, higher proteinuria, and increased steroid use ( P < 0.05 for all). At 1-year course after rituximab initiation, patients receiving Bactrim, compared with those without Bactrim, had a reduced infection incidence (21% vs 32% in AAV-R and 11% vs 17% in MN/MCD/FSGS). Multivariable analysis showed that Bactrim significantly reduced the risk of infection in AAV-R after adjusting for age, sex, race, albumin, and steroid use (HR, 0.53; 95% CI, 0.30-0.94; P = 0.03). In contrast, no significant association was found in the MN/MCD/FSGS group (HR, 0.68; 95% CI, 0.31-1.47; P = 0.33). Limitations Retrospective study. Conclusions Bactrim prophylaxis could be especially beneficial for reducing infection risk in patients with AAV-R undergoing rituximab therapy. Plain-language Summary This study explored whether Bactrim, a commonly used antibiotic, can help prevent severe infections in people with different kidney diseases treated with rituximab, a medication that weakens the immune system. The researchers focused on two groups: one with a systemic autoimmune disease affecting the kidneys (antineutrophil cytoplasmic antibody-associated vasculitis) and another with renal-limited kidney diseases (such as membranous nephropathy, minimal change disease, and primary focal segmental glomerulosclerosis). They found that Bactrim was helpful in reducing infections in patients with systemic disease but did not show the same benefit in patients with kidney-limited conditions. These findings suggest that the benefit of preventive antibiotics may depend on the type of kidney disease, which could help guide more personalized treatment decisions in the future.