Systematic review of evidence and consensus on perianal fistula: an analysis of national and international guidelines

Aim: Treatment of perianal fistula has evolved with the introduction of new techniques and biologicals in Crohn's disease (CD). Several guidelines are available worldwide, but many recommendations are controversial or lack high-quality evidence. The aim of this work was to provide an overview of the current available national and international guidelines for perianal fistula and to analyse areas of consensus and areas of conflicting recommendations, thereby identifying topics and questions for future research.

Method: MEDLINE, EMBASE and PubMed were systematically searched for guidelines on perianal fistula. Inclusion was limited to papers in English less than 10 years old. The included topics were classified as having consensus (unanimous recommendations in at least two-thirds of the guidelines) or controversy (fewer than three guidelines commenting on the topic or no consensus) between guidelines. The highest level of evidence was scored as sufficient (level 3a or higher of the Oxford Centre for Evidence-based Medicine Levels of Evidence 2009, http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/) or insufficient.

Results: Twelve guidelines were included and topics with recommendations were compared. Overall, consensus was present in 15 topics, whereas six topics were rated as controversial. Evidence levels varied from strong to lack of evidence.

Conclusion: Evidence on the diagnosis and treatment of perianal fistulae (cryptoglandular or related to CD) ranged from nonexistent to strong, regardless of consensus. The most relevant research questions were identified and proposed as topics for future research.