Figure 2.

Epidemiology of complex perianal fistula in Crohn’s disease. ¹Chaparro et al[8] published in 2011. Definition of complex perianal fistulas (CPF): A fistula meeting any of the following criteria: High location (high intersphincteric, high transsphincteric, extrasphincteric, or suprasphincteric), multiple external openings, perianal abscess, anal stenosis, or proctitis. Retrospective multicentre study conducted in 11 hospitals in Madrid, Spain (study period was not reported); ²Morete et al[9] published in 2013. Definition of CPF not given. Retrospective single-centre study (Ferrol, Spain) with 15 yr of follow-up; ³Analysis of patients followed up at reporting institution over 15 yr; mean per-patient follow-up not noted. Note: Both studies were presented as conference abstracts only and were not published in a peer-reviewed journal. Thus, data are limited and difficult to assess for robustness. CD: Crohn’s disease; CI: Confidence interval; CPF: Complex perianal fistula; PF: Perianal fistula.