The current meta-analysis is used to summarize the results of existing studies on the effects of LRD and CLD on intestinal preparation and the quality of colonoscopy. In addition, effects of LRD and CLD on the percentage of adenomas detected under colonoscopy were not analyzed in this meta-analysis in 2016.Therefore, a more comprehensive and updated meta-analysis is needed to summarize the initial findings. However, since the release of the meta-analysis, seven clinical trials have been published, and some of the conclusions in these clinical trials are still contradictory.

A meta-analysis of randomized, controlled trials in 2016 showed that there was no difference in adequate intestinal preparation or adverse reactions compared with CLD, but there was a significant increase in tolerance and willingness to repeat preparation in patients with a LRD. Many prospective studies evaluated the quality of intestinal preparation and colonoscopy results as well as overall adverse reactions to the use of a low-residue diet (LRD) and a CLD diet the day before the colonoscopy. With a CLD diet before intestinal preparation, colonoscopy is obviously unlikely to contain food residue, but at the same time, it is difficult for patients to strike a perfect balance between diet orders and the intake of large doses of laxatives, which may affect the effectiveness of colonoscopy. Solid food on this diet is not allowed and any food including water, broth, which is considered as liquid is allowed. Ī diet consisting of exclusively clear liquids is a clear liquid diet (CLD). These reasons may reduce the patient's compliance and lead to poor intestinal preparation. Improper intestinal preparation is often an important cause of inadequate intestinal preparation, such as consuming a large amount of fluid, eating only clear fluid the day before the colonoscopy, and so on. Inadequate intestinal preparation can obviously limit the operator's field of vision and reduce the ability to identify lesions. One of the main factors resulting in the rate of missed diagnosis is the quality of intestinal preparation. However, there is a certain rate of missed diagnosis in colonoscopy. Therefore, this is partly due to the benefits of early screening by colonoscopy, which is of great value in the early identification and treatment of adenomatous polyps or early canceration. In 2016, United States Preventive Services Task Force released new guidelines for CRC screening, which strongly recommends that general risk adults start screening at the age of 50. However, the morbidity and mortality of CRC in some developed countries, especially the United States and Japan, have been decreasing in recent years. However, in terms of the detection rate of intestinal adenomas, the LRD group is not weaker than the CLD group, for its evidence level is high, and can significantly reduce the hunger experience of patients.Ĭolorectal cancer (CRC) is the second most common cancer among women and the third most common cancer among men. Patients with LRD the day before colonoscopy show better tolerance and willingness to repeat intestinal preparation, and no difference with adequate intestinal preparations compared with CLD, but the recommended level of evidence is weak. Patients with LRD compared with CLD indicated significantly better of tolerability (RR 0.92 95% CI,0.85–0.99 P .05).

Total 16 studies (N = 3413) were eligible. Mantel-Haenszel or DerSimonian and Laird models with the relative risk (RR) to evaluate differences in intestinal preparation, tolerance, readiness to repeat preparation, detected of a polyp, and overall adverse reactions. LRD vs CLD before colonoscopy were included in this study. The comprehensive search was performed in PubMed/MEDLINE, Scopus, Cochrane databases (February 2020). Therefore, a more comprehensive and updated meta-analysis is needed to summarize the findings on the effects of LRD and CLD on intestinal preparation and the quality of coloscopy. Several studies have completed using the low-residue diet (LRD) versus a clear liquid diet (CLD) the day before colonoscopy that presenting contradictory results. A clear colonoscopic vision brought by good intestinal preparation will become crucial. Great value in the early identification and treatment of adenomatous polyps or early canceration using colonoscopy has been recognized.

Clear liquid diet colonoscopy