Fistulizing Perianal Disease as a First Manifestation of Crohn's Disease: A Systematic Review and Meta-Analysis

Abstract

Background: Incidences of perianal fistulas (PAFs) as a first manifestation of Crohn's disease (CD) vary widely in the literature. Aim: To analyse the percentage of patients with a PAF preceding CD diagnosis and assess the time to diagnosis. Methods: A systematic literature search was conducted. Studies reporting on patients with a PAF preceding CD diagnosis were identified. Primary outcomes were the (weighted) percentage of patients with CD with a PAF preceding CD and their time to CD diagnosis. Secondary outcomes were the (weighted) percentage of patients with CD with a PAF preceding CD diagnosis in predefined patient subgroups, including (1) sex (men vs. women), (2) ethnicity (Asian vs. non-Asian), and (3) age (paediatric (0-18 y) and patients with elderly onset CD (>60 y) vs. adult patients (18-60 y)). Results: Seventeen studies were included (34,030 patients with CD). In the overall CD population, a PAF preceded CD in 8.6% [95%CI; 5.72; 12.71] with a weighted mean time to CD diagnosis of 45.9 (31.3) months. No studies reported details on sex differences in patients with a PAF as a manifesting sign of CD. In Asian populations, a PAF preceded CD in 17.66% [95%CI; 11.45; 26.25], which was significantly higher when compared with non-Asians (4.99% [95%CI; 3.75; 6.60], OR:3.99, p < 0.0001). In adolescents, an incidence of 9.17% [95%CI; 5.92; 13.93] was found with significantly lower incidences in paediatric patients (6.38% [95%CI; 1.84; 19.85], OR:0.53, p < 0.0001), and elderly-onset patients (3.77% [95%CI; 1.68; 8.25], OR:0.44, p = 0.0035). Conclusions: This systematic review shows that in the literature, almost 10% of patients present with a PAF as a first manifestation of CD, with a mean time to diagnosis of almost four years. These results emphasise that increased clinical awareness is needed.

Keywords: Crohn’s disease; delay; perianal fistula.

Figure 1

Study selection process according to PRISMA guidelines [23].

Figure 2

Forest plot on the weighted mean percentage of PAF first in patients with CD [29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45]. PAF = perianal fistula; CD = Crohn’s disease; CI = confidence interval; p = significance.

Figure 3

(a) Forest plot on the weighted percentage of PAF first in patients with CD in Asian cohort studies [30,35,36,40,42,44,45]. PAF = perianal fistula; CD = Crohn’s disease; CI = confidence interval; p = significance. (b) Forest plot on the weighted percentage of PAF first in patients with CD in non-Asian cohort studies (reference group) [29,31,32,33,34,37,38,39,41,43]. PAF = perianal fistula; CD = Crohn’s disease; CI = confidence interval; p = significance.

Figure 4

(a) Forest plot on the weighted percentage of PAF first in paediatric patients [29,32,35]. PAF = perianal fistula; CD = Crohn’s disease; CI = confidence interval; p = significance. (b) Forest plot on the weighted percentage of PAF first in patients 18–60 years (reference group) [29,30,33,34,36,37,38,39,40,41,42,43,44,45]. PAF = perianal fistula; CD = Crohn’s disease; CI = confidence interval; p = significance. (c) Forest plot on the weighted percentage of PAF first in patients with elderly-onset CD (>60 years) [31,40]. PAF = perianal fistula; CD = Crohn’s disease; CI = confidence interval; p = significance.