Burden and outcomes for complex perianal fistulas in Crohn’s disease: Systematic review

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%

¹Baseline patient characteristics were only reported for 229 patients of whom 19 patients with rectovaginal or rectourethral fistulas were then excluded from the study;

²74% of patients with ileocolonic or colonic disease had complex fistula, compared with 72% of patients with ileal disease only (P = NS);

³NR 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);

⁴Reported 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.