Quantification of Risk for Pouch Failure after Ileal Pouch Anal Anastomosis Surgery

Objective: To identify risk factors associated with ileal pouch failure and to develop a multifactorial model for quantifying the risk of failure in individual patients. Summary Background Data: Ileal pouch anal anastomosis (IPAA) has become the treatment choice for most patients with ulcerative colitis and familial adenomatous polyposis who require surgery. At present, there are no published studies that investigate collectively the interrelation of factors related to ileal pouch failure, nor are there any predictive indices for risk stratification of patients undergoing IPAA surgery. Methods: Data from 23 preoperative, 7 intraoperative, and 10 postoperative risk factors were recorded from 1,965 patients undergoing restorative proctocolectomy in a single center between 1983 and 2001. Primary end point was ileal pouch failure during the follow-up period of up to 19 years. The "CCF ileal pouch failure" model was developed using a parametric survival analysis and a 70%:30% split-sample validation technique for model training and testing. Results: The median patient follow-up was 4.1 year (range, 0-19 years). Five-year ileal pouch survival was 95.6% (95% CI, 94.4-96.7). The following risk factors were found to be independent predictors of pouch survival and were used in the final multivariate model: patient diagnosis, prior anal pathology, abnormal anal manometry, patient comorbidity, pouch-perineal or pouch-vaginal fistulae, pelvic sepsis, anastomotic stricture and separation. The model accurately predicted the risk of ileal pouch failure with adequate calibration statistics (Hosmer Lemeshow χ² = 3.001; P = 0.557) and an area under the receiver operating characteristics curve of 82.0%. Conclusions: The CCF ileal pouch failure model is a simple and accurate way of predicting the risk of ileal pouch failure in clinical practice on a longitudinal basis. It may play an important role in providing risk estimates for patients wishing to make informed choices on the type of treatment offered to them.