S0531 What Is the Ideal Dietary Regimen for Patients Scheduled for Colonoscopy: Low Residue Diet or Clear Liquid Diet? A Meta-Analysis and Systematic Review of Randomized Controlled Trials

Abstract

INTRODUCTION: Colonoscopy screening and early detection of pre-cancerous polyps can significantly reduce both the incidence and mortality of colorectal cancer. The quality of bowel preparation before a colonoscopy is an important predictor of lesion identification. However, patients often cite bowel preparation and associated dietary restrictions as the greatest deterrents to having a colonoscopy. Traditionally, a clear liquid diet (CLD) is required the day before colonoscopy. Recent studies have investigated the use of a low-residue diet (LRD), with varying results. We evaluated various outcomes in patients undergoing colonoscopy who either consumed a CLD versus LRD on the day before colonoscopy. METHODS: A literature search was performed on Scopus, PubMed/MEDLINE, and Cochrane databases (April 2020). Studies included in our meta-analysis involved adult patients undergoing colonoscopy who either consumed a LRD or CLD on the day prior to colonoscopy. Analysis was conducted with the Mantel-Haenszel model using the odds ratio (OR) to assess adequate bowel preparations, tolerability, willingness to repeat diet and preparation, compliance with diet, adenoma and polyp detection rate, and overall adverse effects. RESULTS: 17 studies (4340 patients) were included the analysis. Findings suggest that consuming a LRD demonstrated no differences in terms of adequate bowel preparations (OR 1.31; 95% CI, 0.92–1.86; P = 0.14), compared with a CLD. Subgroup analysis was performed based on the scale used to assess the quality of the bowel preparation (Boston Bowel Preparation Scale, Ottawa Bowel Preparation Scale, and Aronchick Scale) and demonstrated non-inferiority of each. There was higher tolerability (OR 2.21; 95% CI, 1.64–2.98; P < 0.0001) and willingness to repeat preparation (OR 1.90; 95% CI, 1.36–2.67; P = 0.0002) with no differences in compliance with dietary regimen (OR = 1.17; 95% CI, 0.60–2.27; P = 0.64), adenoma detection rate (OR = 1.01; 95% CI, 0.86–1.19; P = 0.92), polyp detection rate (OR = 0.87; 95% CI, 0.87–1.04; P = 0.13), or overall adverse effects (OR 0.90; 95% CI, 0.73–1.13; P = 0 0.37). CONCLUSION: A low residue diet compared to a clear liquid diet prior to colonoscopy resulted in improved patient tolerability and willingness to repeat preparation with no differences in preparation quality. As a less restrictive dietary regimen, the low-residue diet may help improve patient participation in colorectal cancer screening programs.Figure 1.: Forest plot comparing the frequency of adequate bowel preparations while on a low-residue diet compared with a clear liquid diet consumed on the day prior to colonoscopy, performed with a sub-group analysis according to the scale used to determine adequacy of the preparation. BBPS, Boston Bowel Preparation Scale; CI, confidence interval; M-H, Mantel-Haenszel; OBPS, Ottawa Bowel Preparation Scale.