A randomized, blinded, prospective trial to compare the safety and efficacy of three bowel-cleansing solutions for colonoscopy (HSG-01*)

Background and Study Aims: There are conflicting data regarding the optimal bowel preparation for colonoscopy. This study was carried out to compare the efficacy, safety, and tolerability of three widely used bowel lavage solutions: the standard polyethylene glycol-electrolyte solution based on the GoLytely formulation (PEG-EL1; Klean-Prep); a sulphate-free PEG-EL solution based on the NuLytely formulation (PEG-EL2, Endofalk); and a sodium phosphate preparation (NaP, Fleet Phospho-Soda). Patient and Methods: A total of 185 consecutive patients scheduled for elective colonoscopy were prospectively randomly assigned to undergo pre-colonoscopic bowel cleansing with either 41 of PEG-EL1 (n = 64), 3 1 of PEG-EL2 (n = 59), or 90 ml of NaP (n = 62). The quality of preparatory colonic cleansing for each segment from the rectum to the ascending colon was scored on a five-level rating scale (1, very good to 5, very poor) by endoscopists who were blinded with regard to the type of preparation used. The primary outcome measure for the comparison of treatments was the "worst" score in any of the rated bowel segments. Safety and tolerability were evaluated by means of a symptom questionnaire completed by each patient immediately before the procedure. Results: Of the 185 patients who were randomly assigned to one of the three treatments, 175 underwent colonoscopy and 173 were evaluable with regard to efficacy - 59, 54, and 60 patients treated with PEG-EL1, PEG-EL2, and NaP, respectively. The treatment groups were comparable with regard to the baseline characteristics. PEG-EL1 was statistically significantly superior to the other treatments in relation to the "worst cleansing" score (P less than or equal to 0.003). In addition, colonoscopic visualization was markedly better in each of the five bowel segments and general "very good" or "good" ratings were achieved in more than 90% of patients treated with PEG-EL1. The percentages were consistently lower in the other two groups, particularly in the ascending colon. With the exception of the sigmoid, the differences in all segments of the large bowel were statistically significant (P less than or equal to 0.04). Patient satisfaction was comparable between the treatment groups. Adverse events (mainly nausea/vomiting and abdominal pain) and deviations in laboratory values occurred more frequently in the NaP group. Conclusions: Preparatory PEG-EL1 (Klean-Prep) was significantly superior to PEG-EL2 (Endofalk) and NaP (Fleet Phospho-Soda) in achieving effective cleansing of the entire colon prior to colonoscopy. On the basis of these data, PEG-EL1 can be regarded as the "gold standard" for bowel cleansing prior to colonoscopy.