Abstract
Background
Perianal Crohn’s disease (pCD) has a major negative impact on patients’ quality of life and is complex to treat. Despite its putative high frequency and burden for patients, only a few studies have investigated the incidence, disease course and associated cancer-risk in a population-based setting. The aim was to assess the incidence and course of pCD in adult patients with CD within a 19-year period. Specifically, describing changes in medical and surgical management as well as rates of cancer.
Methods
The cohort comprised all individuals >18 years diagnosed with CD in Denmark between 1 January 1997 and 31 December 2015. Patients were identified in the National Patient Registry. Chi-square test, Mann–Whitney–Wilcoxon test and multivariate Cox regression analysis were used.
Results
A total of 1,697/9,739 (17%) patients with CD were found to have pCD. Perianal fistulas were the most common manifestation accounting for 943 (56%) cases. The onset of pCD before CD diagnosis occurred in 32%. The overall incidence of pCD was 20/1,000 patient-years. The incidence of pCD remained stable over time. More patients with pCD were treated with immunomodulators (70%) and biologics (35%) than those without pCD (51%, p < 0.001 and 15%, p < 0.001, respectively). Defunctioning stoma was performed in 157/943 (17%) of perianal fistula patients. Stoma formation in relation to resection was performed in 112/943 (12%) of perianal fistula patients. Patients with pCD were found to have a significantly increased risk of undergoing major abdominal surgery compared with patients without pCD (hazard ratio: 1.52, 95% CI: 1.40 to 1.65, p < 0.001). The incidence rate ratios of anal and rectal cancer in pCD patients were 12.46 (95% CI: 5.07 to 30.59, p < 0.001) and 2.41 (95% CI: 1.31 to 4.42, p = 0.003) respectively, when compared with non-IBD matched controls. The incidence rate ratio of anal and rectal cancer in pCD patients was 2.36 (95% CI: 0.86 to 6.50, p = 0.09) and 1.35 (95% CI: 0.68 to 2.68, p = 0.38) respectively, when compared with CD patients without pCD.
Conclusion
In this nationwide study, 17% of the CD patients developed pCD. The continuing high incidence of pCD suggests a limited disease-modifying effect of biologics. Patients with pCD were at increased risk of undergoing major surgery compared with non-pCD patients. The risk of rectal or anal cancer was increased in patients with pCD compared with non-IBD matched controls. These findings encourage surveillance of rectal and anal cancer.
P813 Occurrence, disease course and prognosis of perianal Crohn’s disease in a Danish population-based inception cohort—a 10-year follow-up study