Background & aims: The interleukin 1 receptor antagonist gene allele 2 has been suggested as a determinant of both disease susceptibility and extent in ulcerative colitis. The aim of this study was to assess the allele as a predictor of both the indication for colectomy and the occurrence of pouchitis after ileal pouch-anal anastomosis formation.
Methods: Genotyping for the +2018 single nucleotide polymorphism in the interleukin 1 receptor antagonist gene was performed in 109 patients who had undergone colectomy, including 82 patients who had been followed prospectively after ileal pouch-anal anastomosis formation.
Results: Patients with pouchitis had a higher allele 2 carriage rate compared with those without pouchitis (72% vs. 45%) and Kaplan-Meier survival analysis showed that allele 2 carriers had a significantly increased incidence of pouchitis compared with noncarriers (log-rank test, 6.5). After adjustment for confounding covariates in a Cox proportional hazards model, the relative hazard was 3.1 (95% confidence interval [CI], 1.2-7.8; P = 0.02). Although there was a higher allele 2 carriage rate in patients with chronic refractory compared with acute severe ulcerative colitis (63% vs. 48%), this difference was not significant (odds ratio, 1.9; 95% CI, 0.9-4.1; P = 0.1).
Conclusions: The interleukin 1 receptor antagonist gene allele 2 predicts pouchitis after ileal pouch-anal anastomosis in ulcerative colitis.