Table 1.
Epidemiology of complex perianal fistula in Crohn’s disease from non-epidemiologic studies
| Ref. | Country, study type | Definition of complex perianal fistula | Sample Size | Mean (SD) age | Sex, % female | Mean CD duration (SD) | Mean fistulising CD duration (SD) | Disease location, % | Proportion of CPF among total fistulas, % |
| Haennig et al[10] 2015 | France, retrospective | According to AGA | 81 | 31 (13) yr; median: 26.9 yr | 52% | NR | Newly referred patients | Perineum: 69% | 88% |
| Rectum: 42% | |||||||||
| Ileum: 7% | |||||||||
| Colon: 40% | |||||||||
| Ileum-colon: 52% | |||||||||
| Active proctitis: 80% | |||||||||
| Alessandroni et al[11] 2013 | Italy, retrospective | Not provided (rectovaginal and rectourethral fistulas were excluded) | 210 | Median, 34 (range 9-74) yr1 | 47%1 | NR | NR | Ileal disease1: 27%, colonic1: 26%, ileocolonic involvement1: 47% | 86% |
| Riss et al[12] 2013 | Austria, Retrospective | Transsphincteric, extrasphincteric, suprasphincteric, and rectovaginal fistulas were classified as complex | 69 | Median, 46.5 (range 18-64) yr | 68% | Median, 202.2 mo (range 29-406.5 mo) | NR | NR | 84% |
| Molendijk et al[13] 2014 | Holland, Retrospective | High intersphincteric, transsphincteric, extrasphincteric, or suprasphincteric were classified as complex | 232 | Median, 29.4 (9.1-77.3) yr | 58% | NR; median age at diagnosis: 22.8 yr (4.0-68.7) | Newly diagnosed patients | Upper GI: 5% | 78% |
| Small bowel: 7% | |||||||||
| Ileocecal: 15% | |||||||||
| Large bowel: 38% | |||||||||
| Small + large bowel: 29% | |||||||||
| Whole GI tract: 1% | |||||||||
| Isolated perianal disease: 6% | |||||||||
| Rectal involvement: 41% | |||||||||
| Lahat et al[14] 2012 | Israel, Retrospective | According to AGA | 52 | 10 yr (9.2; range, 1-37) | 5.3 (6.5; range, 1-29) | Terminal | 75%2 | ||
| Ileum: 35% | |||||||||
| Colon: 27% | |||||||||
| Ileocolon: 39% | |||||||||
| Bell et al[15] 2003 | United Kingdom, Retrospective | Transsphincteric, translevator, supralevator and extrasphincteric perianal fistulas were classified as complex | 110 perianal fistulas3 | Median, 35 (range, 20-91) yr | 53% | Median, 8 (range, 0-32) yr | Median, 3 yr (range, 0-32 yr) | Ileocolonic or colonic: 85%, | 72% of fistulas |
| Rectal involvement: 65% | |||||||||
| Mueller et al[16] 2007 | Germany, Prospective | Complex fistula was defined as rectovaginal or fistula with three or more perianal openings | 88 | Median, 23 (range 8-51) yr4 | 52% | NR | NR | Isolated small intestinal disease4: 4%, isolated colonic disease4: 11%, small intestinal and colonic disease4: 85% | 52% |
Baseline patient characteristics were only reported for 229 patients of whom 19 patients with rectovaginal or rectourethral fistulas were then excluded from the study;
74% of patients with ileocolonic or colonic disease had complex fistula, compared with 72% of patients with ileal disease only (P = NS);
NR how many patients had perianal fistulas or CPF; a total of 87 patients with CD and active fistulas were enrolled; 34 patients (39%) had a single fistula, 24 (28%) had two fistulas and 29 (33%) had three or more fistulas during the course of their disease, giving a total number of fistulas of 169 fistulas, of which 110 were perianal fistulas (79 complex perianal and 31 simple perianal fistulas);
Reported for all 97 patients with perianal disease. Baseline characteristics not reported separately for 88 patients with CD and perianal fistulas. AGA: American Gastroenterological Association; CD: Crohn’s disease; CPF: Complex perianal fistula; GI: Gastrointestinal; NR: Not reported; NS: Not significant.