Influence of adjuvant antibiotics on fistula formation following incision and drainage of anorectal abscesses: a systematic review protocol

BACKGROUND: Development of fistula-in-ano following incision and drainage (I&D) of anorectal abscesses occurs in over 30% of patients. It is associated with significant patient morbidity and societal cost. The use of antibiotics following drainage is controversial, with randomized controlled trials reporting opposing conclusions regarding their influence on the rate of fistula formation. Given the significant burden associated with their development, it is imperative to determine strategies to minimize their occurrence. The objective of this review is to summarize the available evidence on the role of antibiotics following I&D of anorectal abscesses on fistula formation. Secondary objectives include determining if antibiotics are associated with morbidity, repeat presentation to the emergency department, and requirement for reoperation. METHODS/DESIGN: MEDLINE, EMBASE, CINAHL, Cochrane Central Registry of Controlled Trials, http://apps.who.int/trialsearch, and clinicaltrials.gov will be searched to identify published and ongoing unpublished interventional and observational studies evaluating the role of antibiotics post I&D on the incidence of fistula formation. There will be no restriction on language, date, or journal. Title and abstracts as well as full texts will be screened in duplicate based on inclusion and exclusion criteria. The Cochrane Risk of Bias tool and ROBINS-I will be used to assess risk of bias in randomized and non-randomized studies, respectively. Our primary outcome is the incidence of fistula formation; secondary outcomes include morbidity, representation to ED, and reoperation. Study heterogeneity will be calculated with Cochran’s Q test, P value, and I(2) index. SASS (version 9.4) will be used for meta-analysis. DISCUSSION: This is the first study to review the available evidence on adjuvant antibiotics and incidence of fistula formation following I&D of anorectal abscesses. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42018092044 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13643-019-1002-z) contains supplementary material, which is available to authorized users.