Twelve studies were included in the review (n=18,292): 11 retrospective cohort studies (n=17,983) and one case-control study (n=309). Sample sizes ranged from 157 to 13,363.
Mean adenoma detection rate was 28.9% (95% CI 20.4% to 39.3%). Mean adenocarcinoma rdetection rate was 1.7% (95% CI 0.9% to 3.0%). Reach-the-cecum rate was 89.2% of cases (95% CI 80.1% to 94.4%); there was statistically significant heterogeneity between the studies for this outcome (Χ2, p<0.001).
There were no deaths in any of the studies. Four patients experienced bleeding complications and three had colonic perforations; the overall rate of major complications was 0.04% (95% CI 0.01% to 0.07%).
The only outcome with any evidence of publication bias was adenocarcinoma detection.