Improving the view during flexible sigmoidoscopy: a systematic review of published randomized, controlled trials comparing the use of oral bowel preparation versus enema bowel preparation

To systematically analyse the published randomized, controlled trials (RCTs) comparing the use of oral bowel preparation (OBP) versus enema bowel preparation (EBP) for diagnostic or screening flexible sigmoidoscopy. Published RCTs, comparing the use of OBP versus EBP, were analysed using RevMan®, and the combined outcomes were expressed as odds ratios (OR). Eight RCTs evaluating 2457 patients were retrieved from the standard electronic databases. There was significant heterogeneity among included trials. The compliance of the patients (p = 0.32) and the acceptability of both bowel preparation regimens (OR, 1.42; 95 % CI, 0.67, 2.99; z = 0.92; p = 0.36) were similar in both groups. In addition, the incidence of adverse reactions (OR, 0.87; 95 % CI, 0.54, 1.41; z = 0.57; p = 0.57), the risk of incomplete procedure due to poor bowel preparation (p = 0.18) and the incidence of poor bowel preparation (OR, 1.21; 95 % CI, 0.63, 2.33; z = 0.59; p = 0.56) were also similar in both groups. EBP and OBP were equally effective for bowel preparation in patients undergoing flexible sigmoidoscopy. Although this study failed to demonstrate the superiority of EBP, at least equivalent efficacy for bowel cleansing may be extrapolated.