Do adjuvants add to the efficacy and tolerance of bowel preparations? A meta-analysis of randomized trials.

Unlabelled: BACKGROUND AND STUDY AIMS : Recommendations on adjuvant use with bowel preparations remain disparate. We performed a meta-analysis determining the clinical impact of adding an adjuvant to polyethylene glycol (PEG), sodium phosphate, picosulfate (PICO), or oral sulfate solutions (OSS)-based regimens.

Methods: Systematic searches were made of MEDLINE, EMBASE, Scopus, CENTRAL and ISI Web of knowledge for randomized trials from January 1980 to April 2016 that assessed preparations with or without adjuvants, given in split and non-split dosing, and PEG high- (> 3 L) or low-dose (≤ 2 L) regimens. Bowel cleansing efficacy was the primary outcome. Secondary outcomes included patient willingness to repeat the procedure, and polyp and adenoma detection rates.

Results: Of 3093 citations, 77 trials fulfilled the inclusion criteria. Overall, addition of an adjuvant compared with no adjuvant, irrespective of the type of preparation and mode of administration, yielded improvements in bowel cleanliness (odds ratio [OR] 1.23 [1.01 - 1.51]) without greater willingness to repeat (OR 1.40 [0.91 - 2.15]). Adjuvants combined with high-dose PEG significantly improved colon cleansing (OR 1.96 [1.32 - 2.94]). The odds for achieving adequate preparation with low-dose PEG with an adjuvant were not different to high-dose PEG alone (OR 0.95 [0.73 - 1.22]), but yielded improved tolerance (OR 3.22 [1.85 - 5.55]). However, split high-dose PEG yielded superior cleanliness to low-dose PEG with adjuvants (OR 2.53 [1.25 - 5.13]). No differences were noted for OSS and PICO comparisons, or for any products regarding polyp or adenoma detection rates.

Conclusions: Critical heterogeneity precludes firm conclusion on the impact of adjuvants with existing bowel preparations. Additional research is required to better characterize the methods of administration and resulting roles of adjuvants in an era of split-dosing.