Efficacy and Tolerance of 2L Polyethylene Glycol-electrolyte Solution with Sodium Ascorbate and Ascorbic Acid (PEG) Administered Entirely in the Morning (AM-only) Compared to Split Dose (PM/AM) Administration Prior to Afternoon Colonoscopy

Abstract

Purpose: To compare the efficacy and tolerability of AM-only PEG vs split dose PEG for afternoon colonoscopy. Methods: Single center, prospective, randomized, investigator blinded comparison of AM-only PEG to PM/AM PEG for elective afternoon outpt colonoscopy. The PM/AM regimen was 1L at 6pm and 1L 4hrs before colonoscopy, and AM-only dosing was 1L 7 hrs and 1L 4 hrs prior to colonoscopy. Day prior diet was a low residue breakfast followed by clears up to 2.5hrs before colonoscopy. Primary endpoint was prep quality (adequate vs inadequate) for the whole colon. This study had 84% power to establish non-inferiority of AM-only dosing for whole colon cleansing. Secondary endpoints were right colon prep, need for flushing, prep completion, adverse events, and measures of colonoscopy quality and quality of life. Results: 125 pts were randomized and 9 withdrew without taking any prep. Of the 116 analyzed, 54 received PM/AM prep and 62 AM-only prep. One pt in the AM group cancelled due to nausea/vomiting and was included in the tolerance and QOL analyses. The groups were well matched except for a somewhat higher fraction of older pts and women in the AM prep arm. The whole colon prep was adequate in 94.4% of the PM/AM group vs 91.8% in the AM-only group (95% confidence limit (CL) = −11.3%, non-inferiority p=0.013). The right colon prep was adequate for 92.5% in the PM/AM group and 93.3% in the AM-only group (95% CL = −7.8%, non-inferiority p=0.003). Flushing was required in 51.9% of the PM/AM group and 42.6% of the AM-only group (CL=6.4%, non-inferiority p=0.001). Over 90% of both prep doses was taken by 70.9% in the PM/AM group and 85.3% in the AM-only group (95% CI: −1.2% to 29.8%, p=0.073). The AM-only group had a lower incidence (diff = −18.5,95% CI: −34.8% to −1.6%, p=0.039) and severity (p=0.024) of abdominal pain. Incidence of any adverse event was similar between the groups. One AM-only pt had aspiration pneumonia treated with 1 wk of oral antibiotics. Poor prep prevented cecal intubation in 1 AM-only pt. Mean procedure time (total, withdrawal) was similar for both groups. The mean number of total polyps/pt was 0.67 higher in the AM-only group (0.94 vs 1.57, non-inferiority p=0.007). The mean number of adenomas and cancer per pt was 0.24 greater in the AM-only group (0.46 vs 0.70, non-inferiority p=0.047). The AM-only group had better sleep quality (p<0.05) and less interference with work the day prior (p=0.046). Conclusion: AM-only and split dose PEG are equivalent with respect to cleansing efficacy, need for flushing, and adenoma/cancer detection. Compared to split dosing, AM-only prep was associated with a lower incidence and severity of abdominal pain, superior sleep quality, and less interference with work the day prior to colonoscopy. Disclosure: Dr Kastenberg- Consultant, Grant/Research Support, Advisory Committee: Salix Pharmaceuticals, Inc. This research was supported by an industry grant from Salix Pharmaceuticals, Inc.