To Divert or Not to Divert A Retrospective Analysis of Variables That Influence Ileostomy Omission in Ileal Pouch Surgery

Hypothesis: A model could be developed to identify patients who can safely undergo restorative proctocolectomy (RPC) without proximal diversion. Design: Logistic regression analysis was used to identify independent factors favoring omission of ileostomy at the time of RPC. A propensity nomogram was developed and validated using measures of calibration, discrimination, and subgroup analysis. Setting: Two tertiary referral centers. Patients: A total of 4013 patients undergoing RPC between January 1977 and December 2005 were included in the study sample. Main Outcome Measure: The decision to omit loop ileostomy at the time of RPC. Results: After study group exclusions, proximal diversion was performed in 3196 of 3733 patients (85.6%) undergoing RPC; 45.4% of 3733 patients were women. The mean (SD) age at surgery was 37.4 (12.8) years. Ulcerative colitis was the indication for RPC in 2304 patients (61.7%) and familial adenomatous polyposis in 364 patients (9.8%), and a J pouch was performed in 2657 patients (71.2%). The following were found to be associated with ileostomy omission: stapled anastomosis (odds ratio [OR], 6.4), no preoperative corticosteroid use (OR, 3.2), familial adenomatous polyposis diagnosis (OR, 2.6), cancer diagnosis (OR, 3.4), female sex (OR, 1.6), and age at surgery younger than 26 years (OR, 2.1) (P < .01 for all). The model discriminated well (area under the receiver operating characteristic curve, 74.9%), with no significant differences between observed and expected outcomes (P = .49). Omission of proximal diversion demonstrated no significant effect on postoperative adverse events, although it was associated with a 2-day increase in the median length of hospital stay (P < .01). Conclusion: Incorporation of a 5-point nomogram in the preoperative assessment of patients undergoing RPC may aid clinicians in identifying a select group of patients who may be candidates for ileostomy omission during RPC.