Efficacy And Tolerance Of A Low Residue Diet Compared To A Clear Liquid Diet For Intertinal Preparation: Systematic Review And Metaanalysis

Colonoscopy is important to prevent colorectal cancer. Bowel preparation is essential for adequate mucosa visualization. Usually, patients are instructed to consume clear liquids the day before a colonoscopy. However, recent studies have suggested that using a low-residue diet is preferable. Our aim was to assess bowel preparation efficacy, tolerance and adverse effects of low-residue diet (LRD) versus clear liquid diet (CLD) on the day before colonoscopy. PubMed/MEDLINE, Cochrane databases, and CINAHL were searched (October 2019). Randomised control trials involving adult patients undergoing colonoscopy examination and that compared LRD versus CLD on the day before colonoscopy were included. Data extraction and assessment of methodological quality of included studies were independently performed by two authors. Our primary outcome was the rate of adequate bowel preparation measured with validated BBPS, Ottawa, or Aronchick scales. Adequacy was defined as a colonoscopy with a score of 2 or 3 points in each colon segments, Aronchick scale (good or very good) or with Ottawa scale (<6 points). A subgroup analysis for the primary outcome was performed based on timing of bowel preparation less than five hours and split doses. Our secondary outcomes were tolerability and adverse effects. Tolerability of the intestinal preparation was measured by assessing acceptability rate and patients rate who would choose the same preparation in the future. The incidence of adverse effects was measured by assessing the rate of nausea, vomits and abdominal discomfort. Grouped estimates of relative risk (RR) were used for dichotomous variables (adequate bowel preparations, tolerability, and adverse effect). Thirteen RCT studies were included (N = 2587). Patients who received a low residue diet compared to clear liquids showed no differences in adequate bowel preparations (RR 1.01; 95% CI, 0.98-1.04; I2 = 66%), and in adverse effects (RR 0.92; 95% CI, 0.81-1.05; I2 = 0%). Nevertheless, low residue diet compared to clear liquids demonstrated better tolerability (RR 1.15; 95% CI, 1.09-1.22; I2 = 81%). The subgroup analysis for the primary outcome showed no significant differences in adequate bowel preparations between LRD and CLD. (RR 1.01; 95% CI, 0.98-1.04; I2 = 25%). A low-residue diet, a day before the scheduled colonoscopy, improves patients’ tolerance to the bowel preparation process without affecting preparation quality or causing more adverse effects compared to liquid diet.View Large Image Figure ViewerDownload Hi-res image Download (PPT)