Comparison of the Effectiveness of Three Different Combinations for Colonoscopy Preparation: A Multicenter Randomized Clinical Trial

Background/Objectives: High-quality bowel preparation is essential for the diagnostic accuracy of colonoscopy, the gold standard for colorectal cancer screening. In our study, we aimed to compare the efficacy and tolerability of three bowel preparation regimens—Moviprep with Donat Mg, Plenvu, and Plenvu with Donat Mg—commonly used in clinical practice in Slovenia. Methods: This was a randomized, multicenter, blinded clinical trial conducted across three Slovenian gastroenterology centers. A total of 300 consecutive adult patients undergoing elective colonoscopy were randomly assigned to one of the three bowel preparation groups. Bowel cleanliness was evaluated using the Boston Bowel Preparation Scale, and lesion detection was assessed using polyp detection rate (PDR) and adenoma detection rate (ADR). Patients also completed a questionnaire assessing adverse effects, overall tolerability, and willingness to repeat the same regimen. Statistical analyses included ANOVA, chi-square, Kruskal–Wallis, and t-tests. Results: Of the 300 patients included in the final analysis, 94 received Moviprep with Donat Mg, 96 received Plenvu, and 110 received Plenvu with Donat Mg. The mean age of participants was 58.4 ± 15.6 years; 158 patients (52.7%) were male and 142 (47.3%) were female. All three regimens achieved high bowel preparation adequacy (≥95%), with no statistically significant differences in total BBPS scores, PDR, or ADR. Adverse effects were mild and comparable between groups, with thirst and bloating being the most frequently reported symptoms. Patient satisfaction and willingness to repeat the preparation were high across all regimens, with no significant differences. Conclusions: Moviprep with Donat Mg, Plenvu, and Plenvu with Donat Mg are all effective, safe, and well-tolerated bowel preparation regimens. All regimens exceeded ESGE minimum quality standards. While the findings suggest that each regimen is suitable for routine use, the study was not powered to establish equivalence, and regimen selection should therefore continue to consider individual patient characteristics, preferences, and clinical judgment.