Low-Fibre Diet as an Option for Bowel Preparation Prior to Colonoscopy: ARandomised Controlled Clinical Trial

Introduction: Bowel preparation for colonoscopy plays an important role in the evaluation of the colon. Many methods for preparing the colon for colonoscopy do not work well. Aim: To use a low-fibre diet as a standard and applicable method for bowel preparation in performing colonoscopy and increasing patients’ adherence to colonoscopy. Materials and Methods: Clinical control trial design was used to compare bowel preparation in people receiving a low-fibre diet with those who did not receive food {Nil Per Os (NPO)} for bowel preparation. The participants included 477 patients who were randomly divided into two groups including 223 patients having a low-fibre diet (for dinner) and 254 patients having nothing for dinner (NPO). Data were recorded including age, sex, weight, height, level of education, bowel preparation score, colonoscopy diagnosis and sedative dose. Both groups were given a solution of 3 L of ethylene glycol and 60 mg of bisacodyl at three occasions: 3 pm and 7 pm the day before colonoscopy and 6 am on the colonoscopy day. Scoring criteria for colonoscopy preparation included excellent (clean and free of any liquids), very good (clean with clear fluid, underlying mucus visible in clear fluid), good (clean with dirty liquid), poor (with particles including stools, but can be assessed at 80% mucus), and very poor (containing stool particles, and mucosal evaluation below 80%, colonoscopy was cancelled in this group). The data were analysed by SPSS version 21.0 using Chi-square and Independent Samples Test. Results: About 82% of patients who consumed a low-fibre diet for bowel preparation the night before colonoscopy had an excellent and very good quality of bowel preparation compared with 74.9% of patients not receiving any diet. The number of patients who cancelled the colonoscopy were more in the group not receiving any diet (4.7% versus 2.6%). The data indicated that the quality of colon preparation decreased by age (p=0.0001), whereas Body Mass Index (BMI) did not differ on colon cleansing. When having dinner, patients with Irritable Bowel Syndrome (IBS) had significantly more secretion of air bubble and foam formation than patients not eating dinner (p=0.002). The results showed that the difference in bowel preparation quality between the two groups was not significant (p=0.169), and increased patient adherence to colonoscopy in the first group. Conclusion: Implementing a proper bowel preparation method is very important in improving the quality of colonoscopy and increasing the patient’s adherence to colonoscopy. Using a low-fibre diet on the day before colonoscopy can help achieve this goal.