Comparison of efficacy of colonoscopy between the morning and afternoon: A systematic review and meta-analysis

Colonoscopy performed in the afternoon, rather than morning, has been reported to be associated with lower rates of adenoma and polyp detection (ADR and PDR) and cecal intubation (CIR). This meta-analysis evaluated the efficacy of afternoon colonoscopy relative to morning colonoscopy.

The databases MEDLINE, Web of Science, EMBASE, and the Cochrane Library were searched to identify potential relevant studies. The primary outcome was ADR and the secondary outcomes were CIR and PDR. The outcomes were estimated by relative risk (RR) and 95% confidence interval (CI) with a random effects model.

Sixteen studies with 38,063 participants met the inclusion criteria. The pooled analyses indicated that ADR (RR: 1.08, 95% CI: 1.00-1.17) and CIR (RR: 1.01, 95% CI: 1.00-1.02) were stable during the whole day. In subgroup analyses, the effect of full-day block or inferior bowel preparation were more prominent, reflected by a significant reduction of ADR (RR: 1.18, 95% CI: 1.09-1.28; RR: 1.12, 95% CI: 1.01-1.24) and CIR (RR: 1.08, 95% CI: 1.02-1.13; RR: 1.02, 95% CI: 1.01-1.03) in the afternoon, respectively.

Colonoscopy quality, as indicated by the ADR and CIR, is not affected by the time of day for procedures performed in block shifts. However, endoscopists' working full-day blocks and inferior bowel preparation are associated with a significant decrease in ADR and CIR in the afternoon.