Is a split-dose regimen of 2 L polyethylene glycol plus ascorbic acid tolerable for colonoscopy in an early morning visit to a comprehensive medical check-up?

AIM To evaluate the effectiveness and tolerability of a split-dose 2 L polyethylene glycol (PEG)/ascorbic acid (AA) regimen for healthy examinees who visited for comprehensive medical check-up in the early morning. METHODS From February 2015 to March 2015, examinees of average risk who were scheduled for a colonoscopy in the morning were retrospectively enrolled. RESULTS The 189 examinees were divided into split-dose and non-split-dose groups. The adequacy of bowel preparation for the split-dose group vs the non-split-dose group was 96.8% vs 85.2%, respectively, P < 0.001, and the compliance of the last meal restriction was 74.6% vs 58.2%, respectively, P < 0.001. The sleep disturbance (P < 0.001) was more prevalent in the split-dose group, however the willingness to repeat the same preparation method (P = 0.243) was not different in both groups. The split-dose regimen was the most important factor influencing adequate bowel preparation in multivariate analysis (HR = 10.89, 95%CI: 6.53-18.17, P < 0.001). CONCLUSION A split-dose regimen of 2 L PEG/AA for an early morning colonoscopy was more effective and showed better compliance for diet restriction without any difference in satisfaction and discomfort. Introducing a split-dose regimen of 2 L PEG/AA to morning colonoscopy examinees is effective and tolerable in a comprehensive medical check-up setting.