Four RCTs (n=358) were included in the meta-analysis (one published as an abstract only). The results of the quality assessment were not reported. Twenty-six (27 reported in the abstract) retrospective studies (sample size range 70 to 2,729) were included in the wider review.
Pooled analysis showed a statistically significant reduction in anastomotic leakage when using a defunctioning stoma (OR 0.32, 95% CI 0.17 to 0.59, I2 = 0%; four RCTs). There were significantly fewer reoperations associated with leakage following use of a defunctioning stoma (OR 0.27, 95% CI 0.14 to 0.51, I2 = 0%; four RCTs). Perioperative mortality rates were similar between the groups (three RCTs).
When the largest trial (n=234) was removed from the analysis, a trend remained in favour of a defunctioning stoma for leakage rates and a significant difference remained for reoperation rates (p=0.01). Results from the retrospective studies were inconsistent (reported in the paper).