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.