Magnitude, Risk Factors, and Factors Associated With Adenoma Miss Rate of Tandem Colonoscopy: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS: We performed a systematic review and meta-analysis to comprehensively estimate adenoma miss rate (AMR) and advanced AMR (AAMR) and explore associated factors.

METHODS: We searched the PubMed, Web of Science, and Ovid EMBASE databases for studies published through April 2018 on tandem colonoscopies, with AMR and AAMR as the primary outcomes. We performed meta-regression analyses to identify risk factors and factors associated with outcome. Primary outcomes were AMR and AAMR and secondary outcomes were AMR and AAMR for different locations, sizes, pathologies, morphologies, and populations.

RESULTS: In a meta-analysis of 43 publications and more than 15,000 tandem colonoscopies, we calculated miss rates of 26% for adenomas (95% confidence interval [CI] 23%-30%), 9% for advanced adenomas (95% CI 4%-16%), and 27% for serrated polyps (95% CI 16%-40%). Miss rates were high for proximal advanced adenomas (14%; 95% CI 5%-26%), serrated polyps (27%; 95% CI 16%-40%), flat adenomas (34%; 95% CI 24%-45%), and in patients at high risk for colorectal cancer (33%; 95% CI 26%-41%). Miss rates could be decreased by adequate bowel preparation and auxiliary techniques (P = .06; P = .04, and P = .01, respectively). The adenoma detection rate (ADR), adenomas per index colonoscopy, and adenomas per positive index colonoscopy (APPC) were independently associated with AMR (P = .02, P = .01, and P = .008, respectively), whereas APPC was the only factor independently associated with AAMR (P = .006). An APPC value greater than 1.8 was more effective in monitoring AMR (31% vs 15% for AMR P < .0001) than an ADR value of at least 34% (27% vs 17% for AMR; P = .008). The AAMR of colonoscopies with an APPC value below 1.7 was 35%, vs 2% for colonoscopies with an APPC value of at least 1.7 (P = .0005).

CONCLUSIONS: In a systematic review and meta-analysis, we found that adenomas and advanced adenomas are missed (based on AMR and AAMR) more frequently than previously believed. In addition to ADR, APPC deserves consideration as a complementary indicator of colonoscopy quality, if it is validated in additional studies.