Purpose: Patients with chronic ulcerative colitis who undergo proctocolectomy and are found intraoperatively to harbor histologic signs suggesting Crohn's disease have indeterminate colitis; nonetheless, ileal pouch-anal anastomosis is usually performed. The aim of this study was to determine the long-term outcome of ileal pouch-anal anastomosis in patients with indeterminate colitis compared with a cohort of patients with chronic ulcerative colitis.
Method: Review of an ileal pouch-anal anastomosis registry identified 1,437 patients with chronic ulcerative colitis and 82 patients with indeterminate colitis who underwent an ileal pouch-anal anastomosis between 1981 and 1995. The median follow-up was 83 (range, 1-192) months. Demographic data and functional outcomes were compared by chi-squared and Wilcoxon's rank-sum tests. Probabilities of complications and pouch failure were analyzed using Kaplan-Meier and log-rank techniques. Finally, Bonferroni adjustments were used for multiple comparisons.
Results: Patients with indeterminate colitis and chronic ulcerative colitis were comparable in terms of gender and length of follow-up. The mean age of the chronic ulcerative colitis group was higher (34 vs. 31; P < 0.01). At ten years patients with indeterminate colitis had significantly more episodes of pelvic sepsis (17 percent indeterminate colitis vs. 7 percent chronic ulcerative colitis; P < 0.001), pouch fistula (31 vs. 9 percent; P < 0.001), and pouch failure (27 vs. 11 percent; P < 0.001). Importantly, during follow-up fully 15 percent of patients with indeterminate colitis, but only 2 percent of patients with chronic ulcerative colitis, had their original diagnosis changed to Crohn's disease (P < 0.001). When the outcomes of these patients newly diagnosed with Crohn's disease were considered separately, the rate of complications for the remaining patients with indeterminate colitis was identical to that of patients with chronic ulcerative colitis. Functional outcomes were comparable among all three groups.
Conclusion: After ileal pouch-anal anastomosis patients with indeterminate colitis who did not develop Crohn's disease subsequently experienced long-term outcomes nearly identical to patients with chronic ulcerative colitis. Crohn's disease, whether it develops after surgery for chronic ulcerative colitis or indeterminate colitis, is associated with poor long-term outcomes.