High definition colonoscopy vs. standard video endoscopy for the detection of colonic polyps: a meta-analysis.

BACKGROUND AND STUDY AIMS: High definition colonoscopy may improve adenoma detection rates but studies report conflicting results. The aim of this meta-analysis was to compare the diagnostic yield of colonic polyps between high definition colonoscopy and standard video endoscopy (SVE).

METHODS: Various electronic databases were searched for articles reporting on high definition colonoscopy. The pooled incremental yield and pooled weighted mean difference of high definition colonoscopy over SVE for polyp detection was determined.

RESULTS: Five studies involving 4422 patients provided data on the total number of polyps detected. The incremental yield of high definition colonoscopy for the detection of any polyp was 3.8 % (95 % confidence interval [CI] 1 % - 6.7 %) with a number needed to treat (NNT) of 26. For the detection of adenomatous polyps the incremental yield was 3.5 % (95 %CI 0.9 % - 6.1 %) with an NNT of 28. There were no differences between high definition and SVE in the detection of high risk adenomas, with an incremental yield of -0.1 % (95 %CI -1.7 % to 1.6 %). When grouped according to the overall adenoma detection rate of the studies (> 50 % or < 50 %) the pooled weighted mean difference in small adenoma detection was better with high definition colonoscopy ( P = 0.035).

CONCLUSIONS: There were marginal differences between high definition colonoscopy and SVE for the detection of colonic polyps/adenomas. High definition colonoscopy did not improve the detection of high risk adenomas. Due to differences in the adenoma detection rate between the studies and the nonrandomized study design of three of the five studies, these results need to be interpreted with caution. Prospective randomized trials looking at long term outcomes such as rates of interval or missed cancers are needed to clarify the clinical implications.