Seventeen studies were included in the review (n=1,486; 721 diverting ileostomy and 765 without proximal diversion). Of these, one study scored 10, three studies each achieved scores of 7, 6, 5, 4, and 3, and one study scored 2 (out of a possible 12) for study quality.
There were no significant differences between groups for operative details (operative time, length of stay), re-operation (second laparotomy, other operation) or functional outcomes (frequency of defecation, soiling, anal incontinence, antidiarrhoeal medication use). Anastomotic leak was significantly more common in patients without stoma at the time of surgery (11 trials; OR 2.37 (95% CI: 1.39, 4.04) p=0.002). However, other short-term adverse events (pouch-related sepsis, perianal sepsis) showed no significant differences between groups. Failure of the ileal pouch (11 trials; OR 0.30 (95% CI: 0.12, 0.74) p=0.009) and a stricture developed at the pouch-anal anastomosis (five trials; OR 0.31 (95% CI: 0.10, 0.98) p=0.045) were significantly more common in patients with stoma. Other long term adverse events showed no differences between groups.
Sensitivity analyses showed that anastomotic leak remained significant in patients without stoma when only high-quality studies were included. Although the outcomes for sepsis were not significant when all studies were included, they were significantly greater in patients with stoma in studies published since 1995 (four trials; OR 1.80 (95% CI: 1.03, 3.17) p=0.04), in studies with more than 100 patients (six trials; OR 1.72 (95% CI: 1.07, 2.77) p=0.03) and in higher quality trials (six trials; OR 1.90 (95% CI: 1.13, 3.20) p=0.02).
The assessment of publication bias was not reported.