Bowel preparation for small bowel capsule endoscopy: standard regimen with 2 L polyethylene glycol versus 1 L polyethylene glycol plus ascorbate

Background/Aims: Optimization of bowel preparation for small bowel capsule endoscopy (SBCE) is debated. Guidelines recommend 2 L of iso-osmolar polyethylene glycol (PEG) to improve SBCE visibility. We compared the efficacy of the standard 2 L PEG solution with a 1 L PEG plus ascorbate (PEG-ASC) preparation, which has already been established for large-bowel preparation. Methods: Between October 2020 and February 2022, patients undergoing SBCE were assigned to receive 2 L PEG or 1 L PEG-ASC bowel preparation on an even- or odd-day basis. Bowel cleanliness was evaluated using the small bowel mucosal visibility scoring system (SBMVSS). Results: Following propensity score matching using a random forest method, two comparable populations of patients treated with 2 L PEG (n=74, male 41%, 53 +/- 17 years) and 1 L PEG-ASC (n=74, male 42%, 55 +/- 21 years) were obtained from the original cohort of 221 consecutive SBCE patients. Our results showed a trend towards more frequent adequate mucosal visibility with 1 L PEG-ASC compared to 2 L PEG (small bowel mucosal visibility >= 2 in all three small bowel tertiles, p =0.07), as per the SBMVSS score. No significant differences were observed in the diagnostic yield (p=1.00), visibility score=9 (p=0.85), SBCE completeness (p=0.33), or adequate mucosal visibility in each tertile (p=0.61, p =0.74, and p =0.70 for the first, second, and third tertiles, respectively). Conclusions: Our study suggests the non-inferiority of the 1 L PEG-ASC solution over the standard 2 L PEG for SBCE preparation.