Background/aim: Previous studies comparing 2-L polyethylene glycol (PEG)-based solution with ascorbic acid (PEG/Asc) with sodium picosulfate/magnesium citrate (SP/MC) drew inconclusive results. This study aimed to compare a 2-L-PEG/Asc with SP/MC by split method in bowel cleansing efficacy, tolerability, and safety and to identify factors influencing inadequate bowel preparation.
Method: We performed a prospective randomized, endoscopist-blinded, single-center, controlled trial. The Aronchick scale and Ottawa bowel preparation scale (OBPS) were used to evaluate the bowel cleansing efficacy, and patients' tolerability and preferences were assessed by questionnaire.
Results: In total, 223 patients were randomized to receive 2-L-PEG/Asc (n = 109) or SP/MC (n = 114). There was no significant difference in overall bowel cleansing efficacy between the two groups; however, when analyzing by individual segment, mean bowel cleansing efficacy of right colon showed a trend in favor of SP/MC group than in PEG/Asc group (OBPS; 1.55 ± 0.66 vs. 1.74 ± 0.88, P = 0.08). Furthermore, SP/MC was better tolerated than PEG/Asc based on ease of consumption and preference to receive the agents again in the future. Total adverse events were significantly lower in SP/MC group than PEG/Asc group (47.4 vs. 62.4%, P = 0.031). In multivariate analysis, later colonoscopic starting time was the only independent factor predicting inadequate bowel preparation (OR 1.39, 95% CI 1.156-1.692, P = 0.001).
Conclusions: There was no significant difference in overall bowel cleansing efficacy between PEG/Asc and SP/MC; however, SP/MC showed better tolerability and safety profile than PEG/Asc. The independent factor for inadequate bowel preparation was later colonoscopic starting time when applied split method.
Keywords: Ascorbic acid; Bowel preparation; Magnesium citrate; Polyethylene glycol; Sodium picosulfate.