Infection prophylaxis among patients with antineutrophil cytoplasmic antibody (ANCA) vasculitis: a scoping review

Severe infections associated with the use of strong immunosuppressive medication are a leading cause of morbidity and mortality in patients with ANCA vasculitis (AV). While guidelines conditionally recommend trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis for Pneumocystis jirovecii pneumonia in AV patients, robust evidence on prophylaxis strategies is lacking. This scoping review aimed to assess the existing evidence on infection prophylaxis in AV patients, identify knowledge gaps, and guide future study design. A comprehensive search of six databases and relevant references identified original studies in English from January 1, 2000, to July 31, 2020. Inclusion criteria encompassed studies evaluating the impact of any antimicrobial prophylaxis strategy on infection-related outcomes in AV patients receiving immunosuppressive treatment. Studies were screened by four researchers using a blinded approach. Data was extracted by two reviewers, with differences resolved via consensus in consultation with a third reviewer. Nineteen studies met inclusion criteria, including two randomized trials and 17 cohort studies, with TMP-SMX being the most commonly assessed prophylactic strategy. The studies varied in sample sizes, outcomes measured, prophylactic strategies employed, and proportion of patients who received the regimen. Most cohort studies included no or limited control of potential confounding factors. This scoping review suggests significant variation in AV patients' receipt of TMP-SMX and alternative infection prophylaxis approaches. Observational studies using large secondary healthcare databases with rigorous designs are needed to provide high-quality evidence of the real-world effectiveness of antimicrobial prophylactic regimens, to improve clinical decision-making and quality of care for AV patients receiving immunosuppressive treatment.