Comparing Fasting and Low-Residue Diets for Capsule Endoscopy: A Retrospective Analysis of Bowel Preparation Efficacy

Aims Capsule endoscopy (CE) is a non-invasive diagnostic modality that serves as a less invasive alternative to conventional endoscopic procedures. Achieving high completion rates (CRs) and maintaining adequate cleanliness rates (ACRs) are essential quality metrics for CE, with effective bowel preparation being critical to meeting these standards. We performed a retrospective analysis of CE outcomes in patients who underwent a high-residue diet versus those on a fasting regimen to assess the relative efficacy of these preparation methods.

Methods A cohort of 198 consecutive patients that underwent capsule endoscopy were evaluated for image quality. The first 100 patients followed a 24-hour fasting regimen, while the subsequent 98 patients adhered to a 5-day low-residue diet in addition to the 24-hour fast. Bowel preparation quality was assessed through the review of capsule endoscopy footage by two independent assessors at 15-minute intervals. The preparation quality was classified into three categories: adequate (0), average (1), and inadequate (2). The subsequent scores were averaged for each patient and overall imaging scores were also calculated for each diet group.

Results A total of 198 patients were analyzed, comparing the efficacy of a 24-hour fasting regimen (n=100) with a 5-day low-residue diet plus 24-hour fast (n=98). The mean cleanliness scores were 0.60 (SD=0.08) for the fasting group and 0.66 (SD=0.06) for the low-residue diet group, indicating a slight difference in favor of the low-residue diet group. Statistical analysis showed no significant difference between the two groups (p=0.4847). Inter-rater reliability between the two independent assessors was high, with a Pearson correlation coefficient of 0.9892, demonstrating excellent agreement in the assessment of bowel preparation quality.

Conclusions This study suggests that both the 24-hour fasting regimen and the 5-day low-residue diet plus fasting yield acceptable bowel cleanliness scores for capsule endoscopy. Although the low-residue diet group showed a marginally higher mean cleanliness score, the difference was not significant at the 5% level (p=0.4847) but could potentially be significant at the 10% level. The high inter-rater reliability supports the robustness of the cleanliness assessment methodology. These findings indicate that both preparation methods are viable options, and the choice may depend on patient factors such as preference and adherence. Future prospective studies with larger sample sizes are needed to explore potential smaller differences in preparation efficacy between these methods.

Conflicts of Interest

Authors do not have any conflict of interest to disclose.

Publication History

Article published online:
27 March 2025