536 Adenoma Detection Rate Is Higher in a.m. Colonoscopies Only When Performed in Full-Day Blocks: A Systematic Review and Meta-Analysis

Abstract

INTRODUCTION: Colorectal cancer (CRC) is the fourth leading cause of malignancy in the US. Colonoscopy remains the most accurate tool for CRC screening. Adenoma detection rate (ADR) and polyp detection rate (PDR) are important quality indicators for colonoscopy and high rates are associated with decreased post-colonoscopy CRC. Colonoscopy performed in the afternoon has been reported to be associated with lower rates of ADR and PDR, however studies remain controversial. Our aim was to perform a systematic review and meta-analysis to evaluate the ADR and PDR between morning and afternoon colonoscopies. METHODS: We included trials comparing ADR or PDR between morning (AM) and afternoon (PM) colonoscopies. We searched Medline, Google Scholar, and Cochrane through May 2019. Eligible studies were searched for variables of interest. All statistical analyses were performed using the R Programming Language. Pooled rates of variables were reported as Odds ratio (OR) with 95% confidence interval and heterogeneity was reported as I2statistics. RESULTS: A total of 14 trials were eligible and included in the analysis. Colonoscopies were performed in full-day blocks in 3 studies and in half-day blocks in 5. There was a total of 18184 subjects in the AM group and 12326 in the PM group. ADR and PDR were significantly higher in the AM compared to the PM group only when performed in full-day blocks (OR = 1.25, 1.11-1.4; OR = 1.33, 1.13-1.58 respectively). Bowel prep adequacy was similar between the 2 groups (OR = 1.08, 0.8-1.45). There was substantial heterogeneity. CONCLUSION: Colonoscopy quality, as indicated by ADR and PDR is only affected when performing colonoscopies in full-day blocks with lower performance in the afternoon. Endoscopist fatigue, fellow participation and quality of bowel prep are important cofounders when comparing quality metrics in endoscopy. The difference between in ADR and PDR between studies is likely multifactorial, however scheduling colonoscopies in half-day shifts may prevent endoscopist fatigue and improve performance. Given the heterogeneity of the results, definite conclusions cannot be drawn and future randomized trials are needed.