Regime for Bowel Preparation in Patients Scheduled to Colonoscopy: Low-Residue Diet or Clear Liquid Diet? Evidence From Systematic Review With Power Analysis

Colon Bowel Preparation in the Era of Artificial Intelligence: Is There Potential for Enhancing Colon Bowel Cleansing?

BACKGROUND AND OBJECTIVES

Proper bowel preparation is of paramount importance for enhancing adenoma detection rates and reducing postcolonoscopic colorectal cancer risk. Despite recommendations from gastroenterology societies regarding the optimal rates of successful bowel preparation, these guidelines are frequently unmet. Various approaches have been employed to enhance the rates of successful bowel preparation, yet the quality of cleansing remains suboptimal. Intensive bowel preparation techniques, supplementary administration of bowel solutions, and educational interventions aimed at improving patient adherence to instructions have been commonly utilized, particularly among patients at a high risk of inadequate bowel preparation. Expedited strategies conducted on the same day as the procedure have also been endorsed by scientific organizations. More recently, the utilization of artificial intelligence (AI) has emerged for the preprocedural detection of inadequate bowel preparation, holding the potential to guide the preparation process immediately preceding colonoscopy. This manuscript comprehensively reviews the current strategies employed to optimize bowel cleansing, with a specific focus on patients with elevated risks for inadequate bowel preparation. Additionally, the prospective role of AI in this context is thoroughly examined.

CONCLUSIONS

While a majority of outpatients may achieve cleanliness with standard cleansing protocols, dealing with hard-to-prepare patients remains a challenge. Rescue strategies based on AI are promising, but such evidence remains limited. To ensure proper bowel cleansing, a combination of strategies should be performed.

Effect of Visual Booklets to Improve Bowel Preparation in Colonoscopy: Systematic Review with Meta-Analysis

An optimal bowel preparation for colonoscopy is essential to increasing the quality of the examination. Visual booklets have been proposed with conflicting results to enhance bowel preparation. A literature search was performed in March 2023 in the most important databases. Only RCTs were selected. We calculated odd ratios (OR) for dichotomous outcomes. Mean differences (MD) or standardized mean differences (SMD) were used for continuous outcomes. We estimated heterogeneity with the Chi² and the I² statistics. In cases of high heterogeneity, a random effect model was used. Six studies were selected, enrolling 1755 patients overall. Adequate bowel preparation was observed in 86.7% of the booklet group versus 77.5% of the control group, with an OR = 2.31 in favor of the booklet. In studies using a 4-L PEG-based preparation, no difference compared to controls was observed, while in non-PEG formulations, preparation with booklets was better than in controls (OR = 5.10, 95% CI 1.82-14.27, p = 0.002). Two studies were performed in an inpatient setting without any differences between booklets and controls, while outpatients receiving booklets had better results (OR = 7.13, 95% CI 5.39-9.45, p < 0.001). The adenoma detection rate was similar between the two groups. In conclusion, booklets are useful to improve bowel preparation. Outpatient settings and preparations not containing PEG could benefit more from booklets.

Factors affecting the quality of bowel preparation for colonoscopy in hard-to-prepare patients: Evidence from the literature

Adequate bowel cleansing is critical for a high-quality colonoscopy because it affects diagnostic accuracy and adenoma detection. Nevertheless, almost a quarter of procedures are still carried out with suboptimal preparation, resulting in longer procedure times, higher risk of complications, and higher likelihood of missing lesions. Current guidelines recommend high-volume or low-volume polyethylene glycol (PEG)/non-PEG-based split-dose regimens. In patients who have had insufficient bowel cleansing, the colonoscopy should be repeated the same day or the next day with additional bowel cleansing as a salvage option. A strategy that includes a prolonged low-fiber diet, a split preparation regimen, and a colonoscopy within 5 h of the end of preparation may increase cleansing success rates in the elderly. Furthermore, even though no specific product is specifically recommended in the other cases for difficult-to-prepare patients, clinical evidence suggests that 1-L PEG plus ascorbic acid preparation are associated with higher cleansing success in hospitalized and inflammatory bowel disease patients. Patients with severe renal insufficiency (creatinine clearance < 30 mL/min) should be prepared with isotonic high volume PEG solutions. Few data on cirrhotic patients are currently available, and no trials have been conducted in this population. An accurate characterization of procedural and patient variables may lead to a more personalized approach to bowel preparation, especially in patients undergoing resection of left colon lesions, where intestinal preparation has a poor outcome. The purpose of this review was to summarize the evidence on the risk factors influencing the quality of bowel cleansing in difficult-to-prepare patients, as well as strategies to improve colonoscopy preparation in these patients.

Key factors for improving adenoma detection rate

INTRODUCTION

Colonoscopy is a fundamental tool in colorectal cancer (CRC) prevention. Nevertheless, one-fourth of colorectal neoplasms are still missed during colonoscopy, potentially being the main reason for post-colonoscopy colorectal cancer (PCCRC). Adenoma detection rate (ADR) is currently known as the best quality indicator correlating with PCCRC incidence.

AREAS COVERED

We performed a literature review in order to summarize evidences investigating key factors affecting ADR: endoscopists education and training, patient management, endoscopic techniques, improved navigation (exposition defect), and enhanced lesions recognition (vision defect) were considered.

EXPERT OPINION

'Traditional' factors, such as split dose bowel preparation, adequate withdrawal time, and right colon second view, held a significant impact on ADR. Several devices and technologies have been developed to promote high-quality colonoscopy, however artificial intelligence may be considered the most promising tool for ADR improvement, provided that endoscopists education and recording are guaranteed.

From advanced diagnosis to advanced resection in early neoplastic colorectal lesions: Never-ending and trending topics in the 2020s

Colonoscopy represents the most widespread and effective tool for the prevention and treatment of early stage preneoplastic and neoplastic lesions in the panorama of cancer screening. In the world there are different approaches to the topic of colorectal cancer prevention and screening: different starting ages (45-50 years); different initial screening tools such as fecal occult blood with immunohistochemical or immune-enzymatic tests; recto-sigmoidoscopy; and colonoscopy. The key aspects of this scenario are composed of a proper bowel preparation that ensures a valid diagnostic examination, experienced endoscopist in detection of preneoplastic and early neoplastic lesions and open-minded to upcoming artificial intelligence-aided examination, knowledge in the field of resection of these lesions (from cold-snaring, through endoscopic mucosal resection and endoscopic submucosal dissection, up to advanced tools), and management of complications.

Efficacy and tolerability of a low-residue diet for bowel preparation: systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) contributes significantly to cancer mortality worldwide. In an effort to reduce the risk of death, detection of polyps through colonoscopy is crucial. The success of the colonoscopy depends on the diet administered the day before the test. Our aim was to evaluate the efficacy, tolerability, and adverse effects of bowel preparation when using a low-residual diet (LRD) compared to a clear-liquid diet (CLD) the day before a scheduled colonoscopy.

METHODS

PubMed/Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) and Scopus databases were searched. We included studies of patients undergoing a scheduled colonoscopy for CRC screening and surveillance or for diagnostic purposes that compared a LRD with a CLD the day before the colonoscopy. Efficacy, the primary outcome, was evaluated as the rate of adequate bowel preparation. Secondary outcomes were tolerability and adverse effects of bowel preparation.

RESULTS

Thirteen RCTs (N = 2587) were included. Patients receiving a LRD compared to a CLD showed no difference in adequate bowel preparations (RR 1.02; 95% CI 0.99-1.05; I² = 60%). However, the LRD improved patient tolerability (RR 1.17; 95% CI 1.12-1.23; I² = 66%) and had fewer adverse effects (RR 0.89; 95% CI 0.84-0.94; I² = 73%) compared to the CLD. Groups using a LRD with 4L of polyethylene glycol in a single dose or a LRD with < 2000 kcal < 32 g of fibres/day had better tolerability.

CONCLUSION

Based on these findings, our recommendation is strong in favour of a LRD for bowel preparation of patients undergoing a scheduled colonoscopy. This diet could also be useful as a preoperative colonic preparation, but this requires further research.

Single-Day Low-Residue Diet Prior to Colonoscopy Demonstrates Improved Bowel Preparation Quality and Patient Tolerance over Clear Liquid Diet: A Randomized, Single-Blinded, Dual-Center Trial

BACKGROUND AND AIMS

Patients often refer to bowel preparation and associated dietary restrictions as the greatest deterrents to having a colonoscopy completed or performed. Large studies comparing a low-residue diet (LRD) and a clear liquid diet (CLD) are still limited. The aim of this study is to compare LRD and CLD with regard to bowel preparation quality, tolerance, and satisfaction among a diverse patient population.

METHODS

This study is a dual-center, randomized, single-blinded, prospective trial involving adult patients undergoing outpatient colonoscopy at the University of California Irvine Medical Center and an affiliated Veterans Administration hospital. Patients were randomized to consume either a CLD or a planned LRD for the full day prior to colonoscopy. Both groups consumed 4L split-dosed PEG-ELS. The adequacy of bowel preparation was evaluated using the Boston Bowel Preparation Score (BBPS). Adequate preparation was defined as a BBPS ≥ 6 with no individual segment less than a score of 2. Hunger and fatigue pre - and post-procedure were graded on a ten-point scale. Nausea, vomiting, bloating, abdominal cramping, overall discomfort, satisfaction with the diet, willingness to repeat the same preparation and overall experience were assessed.

RESULTS

A total of 195 subjects who underwent colonoscopy from October 2014 to October 2017 were included. The mean BBPS for the LRD and CLD groups was 8.38 and 7.93, respectively (p = 0.1). There was a significantly higher number of adequate preparations in the LRD group compared to CLD (p = 0.05). Evening hunger scores just before starting the bowel preparation were significantly lower in the LRD than the CLD group, 2.81 versus 5.97, respectively (p = 0.006). Subjects in the LRD group showed significantly less nausea (p = 0.047) and bloating (p = 0.04). Symptom scores for vomiting, abdominal cramping, and overall discomfort were similar between the groups. Satisfaction with diet was significantly higher in the LRD group than CLD, 72% versus 37.66%, respectively (p < 0.001). The overall colonoscopy experience and the satisfaction with the preparation itself were also better reported in the LRD group (p < 0.001 and p = 0.002, respectively).

CONCLUSIONS

This study, which included a diverse group of patients, demonstrated that patients using a LRD before colonoscopy achieve a bowel preparation quality that is superior to patients on a CLD restriction. This study shows that a low-residue diet improves patient satisfaction and results in significantly better tolerability of bowel preparation. As a less restrictive dietary regimen, the low-residue diet may help improve patient participation in colorectal cancer screening programs.

Novel frontiers of agents for bowel cleansing for colonoscopy

The incidence of colorectal cancer (CRC) is characterized by rapid declines in the wake of widespread screening. Colonoscopy is the gold standard for CRC screening, but its accuracy is related to high quality of bowel preparation (BP). In this review, we aimed to summarized the current strategy to increase bowel cleansing before colonoscopy. Newly bowel cleansing agents were developed with the same efficacy of previous agent but requiring less amount of liquid to improve patients’ acceptability. The role of the diet before colonoscopy was also changed, as well the contribution of educational intervention and the use of adjunctive drugs to improve patients’ tolerance and/or quality of BP. The review also described BP in special situations, as lower gastrointestinal bleeding, elderly people, patients with chronic kidney disease, patients with inflammatory bowel disease, patients with congestive heart failure, inpatient, patient with previous bowel resection, pregnant/lactating patients. The review underlined the quality of BP should be described using a validate scale in colonoscopy report and it explored the available scales. Finally, the review explored the possible contribution of bowel cleansing in post-colonoscopy syndrome that can be related by a transient alteration of gut microbiota. Moreover, the study underlined several points needed to further investigations.

Comparative Effectiveness of Enhanced Patient Instructions for Bowel Preparation Before Colonoscopy: Network Meta-analysis of 23 Randomized Controlled Trials

Background

Various enhanced patient instructions (EPIs) have been used for bowel preparation (BP) and our previous meta-analysis also demonstrated the efficacy of EPIs in increasing the colonic polyp and adenoma detection rates; however, the optimal method for adequate BP has not yet been developed.

Objective

We performed a network meta-analysis to determine the optimal instructions.

Methods

We searched for randomized controlled trials (RCTs) comparing the effectiveness of EPIs with each other or standard patient instructions (SPIs) for BP. We performed direct and Bayesian network meta-analyses for all instructions and used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria to appraise the quality of evidence.

Results

We included 23 RCTs (7969 patients) comparing 10 different instructions. In direct meta-analyses, most of the EPIs, except visual aids and mobile apps, increased the adequate preparation rate (APR). Network meta-analyses showed that additional explanations were superior to visual aids (odds ratio [OR] 0.35, 95% CI 0.19-0.59), telephone calls (OR 0.62, 95% CI 0.37-0.99), educational videos (OR 0.79, 95% CI 0.5-0.77), and mobile apps (OR 0.33, 95% CI 0.14-0.68) with low-to-high-quality evidence; newly designed booklets (OR 3.28, 95% CI 1.59-6.16), SMS text messaging (OR 2.33, 95% CI 1.28-3.91), telephone calls (OR 1.86, 95% CI 1.03-1.78), educational videos (OR 2.33, 95% CI 1.40-3.65), and social media applications (OR 2.42, 95% CI 1.4-3.93) were superior to visual aids and mobile apps with low-to-high-quality evidence. SMS text messaging, telephone calls, and social media applications increase adherence to and satisfaction with the BP regime. Social media applications reduce the risk of adverse events (AEs). Telephone calls and social media applications increase the polyp detection rate (PDR).

Conclusions

Newly designed booklets, telephone calls, educational videos, and social media applications can improve the quality of BP. Telephone calls and social media applications improve adherence to and satisfaction with the BP regime, reduce the risk of AEs, and increase the PDR.

Trial Registration

INPLASY (International Platform of Registered Systematic Review and Meta-analysis Protocols) INPLASY2020120103; https://inplasy.com/inplasy-2020-12-0103/

A Systematic Review and Meta-Analysis of Low-Residue Diet Versus Clear Liquid Diet: Which Is Better for Bowel Preparation Before Colonoscopy?

The goal of this systematic review was to compare the clear liquid diet and the low-residue diet to determine which is better for bowel preparation before colonoscopy. A literature search for randomized controlled trials on the effects of employing the clear liquid diet and low-residue diets before colonoscopy was conducted in major online English databases (PubMed, Web of Science, and Ovid EMBASE). After the systematic review of all 16 studies, the outcomes including quality of bowel preparation, tolerance, willingness to repeat, and adverse effects were analyzed through meta-analysis. The statistical analysis was performed by using RevMan 5.3 software. No statistically significant difference was observed between the low-residue diet and clear liquid diet groups (odds ratio [95% confidence interval] = 1.19 [0.79, 1.81]; p = .41). There was no statistically significant difference between the Boston Bowel Preparation Scale (standard mean difference [95% confidence interval] =-0.04 [-0.21, -0.14]; p = .68) Ottawa Bowel Preparation Scale (standard mean difference [95% confidence interval] =-0.04 [-0.19, 0.11]; p = .59) scores of the two groups. The quality indicators for colonoscopy of the two groups were not statistically significant. However, patient tolerance to the low-residue diet was higher (odds ratio [95% confidence interval] = 1.86 [1.47, 2.36]; p < .01). More patients in the low-residue diet group were willing to repeat the low-residue diet for bowel preparation (odds ratio [95% confidence interval] = 2.34 [1.72, 3.17]; p < .01). More patients in the clear liquid diet group experienced hunger, nausea, and vomiting. People who employed the low-residue diet before colonoscopy had the same quality of bowel preparation as those with clear liquid diet. Meanwhile, the tolerance of people with low-residue diet was better than people with clear liquid diet, and these people were more willing to repeat the colonoscopy with less adverse events.

Comparable quality of bowel preparation with single-day versus three-day low-residue diet: Randomized controlled trial

BACKGROUND AND AIMS

There is controversy about the length of low-residue diet (LRD) for colonoscopy preparation. The aim of the study was to compare one-day vs. three-day LRD associated to standard laxative treatment for achieving an adequate colonoscopy preparation in average risk subjects with positive fecal immunochemical test undergoing screening colonoscopy.

METHODS

A non-inferiority, randomized, controlled, parallel-group clinical trial was performed in the setting of average risk colorectal cancer screening program. Participants were randomized to receive 1-day vs. 3-day LRD in addition to standard polyethilenglicol treatment. Adequacy of preparation was evaluated using the Boston Bowel Preparation Scale (BBPS). Primary outcome was achieving a BBPS ≥ 2 in all colon segments. Analysis was performed for a non-inferiority margin of 5%, a 95% statistical power and one-sided 0.05 significance level.

RESULTS

A total of 855 patients were randomized. Adequate bowel preparation was similar between groups: 97.9% of patients in the 1-day LRD group vs 96.9% in the 3-day LRD group achieved the primary outcome (P-value for non-inferiority < 0.001). The percentage of patients with BBPS scores ≥ 8 was superior in the 1-day LRD group (254 vs 221 in the 3-day LRD group, P = 0.032). The 1-day regimen was better tolerated than the 3-day diet. 47.7% (vs 28.7%, P < 0.05) of patients rated the 1-day LRD as very easy to follow.

CONCLUSION

The 1-day LRD is non-inferior to 3-day LRD for achieving an adequate colon cleansing before average risk screening colonoscopy and it is better tolerated.

Impact of Prepackaged Low-Residue Diet on Bowel Preparation for Colonoscopy: A Meta-analysis

This meta-analysis aimed to evaluate the impact of prepackaged low-residue diet (PLRD) on bowel preparation for colonoscopy. We searched PubMed, Web of Science, EMBASE, and Cochrane Library databases from inception to August 2020. Randomized controlled trials (RCTs) comparing PLRD with clear liquid diet (CLD) or self-prepared LRD were considered for inclusion. The analysis calculated the odds ratio (OR) for the rate of adequate bowel preparation, patient tolerance, willingness to repeat bowel preparation, tolerability of bowel preparation, and overall adverse effects. Five RCTs published between 2006 and 2019 (N = 561) were included in our meta-analysis. Compared with the traditional CLD or self-prepared LRD, PLRD showed significantly higher rates of adequate bowel preparation (OR, 2.16; 95% confidence interval [CI], 1.18-3.98; p = .01), patient tolerance (OR, 1.99; 95% CI, 1.30-3.07; p = .002), and willingness to repeat the bowel preparation (OR, 1.68; 95% CI, 1.05-2.70; p = .03), with no differences in adverse events (OR, 0.93; 95% CI, 0.59-1.46; p = .75). Prepackaged low-residue diet improved bowel preparation quality, patient tolerance, and willingness to repeat bowel preparations. Importantly, PLRD does not increase the incidence of adverse events. This suggests that it is effective and safe to use PLRD for bowel preparation before colonoscopy.

Enhanced Patient Education for Colonic Polyp and Adenoma Detection: Meta-Analysis of Randomized Controlled Trials

Background

To improve patients’ comprehension of bowel preparation instructions before colonoscopy, enhanced patient education (EPE) such as cartoon pictures or other visual aids, phone calls, mobile apps, multimedia education and social media apps have been proposed. However, it is uncertain whether EPE can increase the detection rate of colonic polyps and adenomas.

Objective

This meta-analysis aimed to evaluate the efficacy of EPE in detecting colonic polyps and adenomas.

Methods

We searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials from their inception to June 2019 for the identification of trials comparing the EPE with standard patient education for outpatients undergoing colonoscopy. We used a random effects model to calculate summary estimates of the polyp detection rate (defined as the number of patients with at least one polyp divided by the total number of patients undergoing selective colonoscopy), adenoma detection rate (defined as the number of patients with at least one adenoma divided by the total number of patients undergoing selective colonoscopy), advanced adenoma detection rate (defined as the number of patients with at least one advanced adenoma divided by the total number of patients undergoing selective colonoscopy), sessile serrated adenoma detection rate (defined as the number of patients with at least one sessile serrated adenoma divided by the total number of patients undergoing selective colonoscopy), cancer detection rate (defined as the number of patients with at least one cancer divided by the total number of patients undergoing selective colonoscopy), or adenoma detection rate - plus (defined as the number of additional adenomas found after the first adenoma per colonoscopy). Moreover, we conducted trial sequential analysis (TSA) to determine the robustness of summary estimates of all primary outcomes.

Results

We included 10 randomized controlled trials enrolling 4560 participants for analysis. The meta-analysis suggested that EPE was associated with an increased polyp detection rate (9 trials; 3781 participants; risk ratio [RR] 1.19, 95% CI 1.05-1.35; P<.05; I²=42%) and adenoma detection rate (5 trials; 2133 participants; RR 1.37, 95% CI 1.15-1.64; P<.001; I2=0%), which were established by TSA. Pooled result from the inverse-variance model illustrated an increase in the sessile serrated adenoma detection rate (3 trials; 1248 participants; odds ratio 1.76, 95% CI 1.22-2.53; P<.05; I²=0%). One trial suggested an increase in the adenoma detection rate - plus (RR 4.39, 95% CI 2.91-6.61; P<.001). Pooled estimates from 3 (1649 participants) and 2 trials (1375 participants) generated no evidence of statistical difference for the advanced adenoma detection rate and cancer detection rate, respectively.

Conclusions

The current evidence indicates that EPE should be recommended to instruct bowel preparation in patients undergoing colonoscopy because it can increase the polyp detection rate, adenoma detection rate, and sessile serrated adenoma detection rate. However, further trials are warranted to determine the efficacy of EPE for advanced adenoma detection rate, adenoma detection rate - plus, and cancer detection rate because of limited data.

A Theory-based Educational Pamphlet With Low-residue Diet Improves Colonoscopy Attendance and Bowel Preparation Quality

GOALS/BACKGROUND

Patients who "no-show" for colonoscopy or present with poor bowel preparation waste endoscopic resources and do not receive adequate examinations for colorectal cancer (CRC) screening. Using the Health Belief Model, we modified an existing patient education pamphlet and evaluated its effect on nonattendance rates and bowel preparation quality.

STUDY

We implemented a color patient education pamphlet to target individual perceptions about CRC and changed bowel preparation instructions to include a low-residue diet instead of the previous clear liquid diet. We compared the nonattendance rate over a 2-month period before and after the introduction of the pamphlet, allowing for a washout period during which pamphlet use was inconsistent. We compared the Boston Bowel Preparation Scale (BBPS) in 100 consecutive patients who underwent colonoscopy during each of the 2 periods.

RESULTS

Baseline characteristics between the 2 groups were similar, although patients who received the pamphlet were younger (P=0.03). The nonattendance rate was significantly lower in patients who received the pamphlet (13% vs. 21%, P=0.01). The percentage of patients with adequate bowel preparation increased from 82% to 86% after introduction of the pamphlet, although this was not statistically significant (P=0.44). The proportion of patients with a BBPS score of 9 was significantly higher in the pamphlet group (41% vs. 27%, P=0.03). There was no difference in adenoma and sessile serrated adenoma detection rates before and after pamphlet implementation.

CONCLUSIONS

After implementing a theory-based patient education intervention with a low-residue diet, our absolute rate for colonoscopy nonattendance decreased by 8% and the proportion of patients with a BBPS score of 9 increased by 14%. The Health Belief Model appears to be a useful construct for CRC screening interventions.

A 3-day low-fibre diet does not improve colonoscopy preparation results compared to a 1-day diet: A randomized, single-blind, controlled trial

Background

Although a 1-day low-fibre diet before colonoscopy is currently recommended, some endoscopists prescribe a 3-day diet.

Objective

The objective of this study was to compare the influence of a 3-day versus a 1-day low-fibre diet on bowel preparation quality, patient tolerability and adherence.

Methods

Outpatients scheduled for total colonoscopy were randomized in two groups, 3-day versus 1-day low-fibre diet, performing a 4-litre polyethylene glycol split-dose. The primary outcome was a reduction of inappropriate preparations in the 3-day low-fibre diet arm from 15% to 5% (bowel preparation was assessed by the Boston Bowel Preparation Scale). Secondary outcomes were adherence to, difficulty to perform, difficulty to obtain and willingness to repeat the diet. Intention-to-treat (ITT) and per-protocol (PP) analyses were conducted for the primary outcome.

Results

A total of 412 patients were randomized (206 per group). Bowel preparation quality was similar between groups. On ITT analysis (n = 412), adequate bowel preparation was 91.7% (3-day diet) versus 94.7% (1-day diet), p = 0.24 and on PP analysis (n = 400) 93.5% versus 96.5%, respectively, p = 0.16. Difficulty to perform the diet was significantly higher on the 3-day diet, p = 0.04. No differences were found on difficulty to obtain the diet, willingness to repeat the diet, adverse events and intra-colonoscopy findings.

Conclusion

A 3-day low-fibre diet does not bring benefit to the bowel preparation quality and is harder to perform than a 1-day diet.

Strategies to Improve Inadequate Bowel Preparation for Colonoscopy

Bowel cleansing is one of the most important parameters included in the evaluation of colonoscopy quality. The available evidence suggests that inadequate bowel preparation reduces the diagnostic yield of colorectal neoplasia and increases post-colonoscopy colorectal cancer risk. Nowadays, up to 30% of patients referred for colonoscopy have a poor bowel cleansing. Recently, several studies have analyzed the risk factors for inadequate bowel cleansing as well as the strategies to optimize bowel preparation. In this review, we have focused on summarizing the available evidence in this field.

Randomized Controlled Trial: Split-dose and Same-day Large Volume Bowel Preparation for Afternoon Colonoscopy Have Similar Quality of Preparation

GOALS

We compare bowel cleanliness in patients taking same-day versus split-dose 4-L polyethylene glycol laxative for afternoon colonoscopy. Secondary objectives included patient satisfaction, adverse effects and patient tolerability.

BACKGROUND

Afternoon colonoscopies have been associated with inadequate bowel preparation and lower adenoma detection rates. Same-day (morning) or split-dosing of the laxative have improved preparation quality but differences between these options are unclear.

MATERIALS AND METHODS

Single-center prospective randomized endoscopist blinded trial. Patients aged 18 years and above prescribed 4-L polyethylene glycol for colonoscopy were randomized into same-day or split-dose preparation. Preparation quality was assessed using the Ottawa Bowel Preparation Scale. Patient satisfaction and side effects was collected using a questionnaire. Intention-to-treat and per-protocol analysis were performed.

RESULTS

A total of 300 patients (158 split-dose, 142 same-day) were evaluated. No statistically significant difference was seen on total Ottawa score among the groups (P=0.47) or by individual colonic segments in intent-to-treat and per-protocol analysis. Patients in split-dose group were more likely to complete the entire preparation (P=0.01) but reported more sleep loss (P=0.001). The same-day preparation group reported higher incidence of vomiting (P=0.036). Patients ingesting bowel preparation ≥7 hours before colonoscopy had higher total Ottawa scores (P=0.001).

CONCLUSIONS

There were no differences in quality of preparation in patients taking same-day versus split-dose preparation for afternoon colonoscopy. Those receiving same-day preparation were less likely to lose sleep but more likely to have emesis. These differences should be considered when selecting a bowel preparation regimen.

Efficacy, Tolerability, and Safety of Low-Volume Bowel Preparations for Patients with Inflammatory Bowel Diseases: The French Multicentre CLEAN Study

BACKGROUND

Standard high-volume polyethylene glycol [PEG] bowel preparations [PEG-4L] are recommended for patients with inflammatory bowel disease [IBD] undergoing colonoscopy. However, low-volume preparations [≤2 L of active volume] are often used in clinical practice. The aim of this study was to evaluate the efficacy, tolerability, and safety of the various bowel preparations for patients with IBD, including low-volume preparations.

METHODS

We conducted a French prospective multicentre observational study over a period of 1 month. Patients aged 18-75 years with IBD with an indication of colonoscopy independent of the study were enrolled. The choice of the preparation was left to the investigators, as per their usual protocol. The patients' characteristics, disease, and colonoscopy characteristics were recorded, and they were given self-reported questionnaires.

RESULTS

Twenty-five public and private hospitals enrolled 278 patients. Among them, 46 had a disease flare and 41 had bowel stenoses. Bowel preparations for colonoscopy were as follows: 42% received PEG-2L, 29% received sodium picosulfate [Pico], 15% received PEG-4L, and 14% had other preparations. The preparation did not reach the Boston's score efficacy outcome in the PEG-4L group in 51.2% of the patients [p = 0.0011]. The preparation intake was complete for 59.5% in the PEG-4L group, compared with 82.9% in the PEG-2L group and 93.8% in the Pico group [p < 0.0001]. Tolerability, as assessed by the patients' VAS, was significantly better for both Pico and PEG-2L compared with PEG-4L, and better for Pico compared with PEG-2L [p = 0.008; p = 0.0003]. In multivariate analyses, low-volume preparations were independent factors of efficacy and tolerability. Adverse events occurred in 4.3% of the patients.

CONCLUSIONS

Preparations with PEG-2L and Pico were equally safe, with better efficacy and tolerability outcomes compared with PEG-4L preparations. The best efficacy/tolerance/safety profile was achieved with the Pico preparation.

A Randomized Trial of Split Dose 3 L Polyethylene Glycol Lavage Solution, 2 L Polyethylene Glycol Lavage Combined With Castor Oil, and 1 L of Polyethylene Glycol Lavage Solution Combined With Castor Oil and Ascorbic Acid for Preparation for Colonoscopy

Background: Castor oil (CaO) has the potential of halving the required volume of bowel preparation solution; however, no clinical trial investigated the efficacy of CaO on bowel preparation for colonoscopy in addition to polyethylene glycol (PEG).

Objectives: Our aim was to evaluate efficacy and safety of lower dose PEG together with 30 mL CaO alone or plus ascorbic acid (Asc) in bowel preparation before colonoscopy.

Methods: Two hundred and forty-six patients were allocated randomly to ingest 2 L PEG with 30 mL CaO, 1 L PEG with 30 mL CaO plus 5 g Asc, or 3 L PEG. We used Boston Bowel Preparation Scale (BBPS) to evaluate bowel preparation efficacy. We also determined other outcomes such as procedure time, polyp or adenoma detection rate, and adverse events (AEs).

Results: Of 282 patients recruited, 36 were excluded. Groups were matched for baseline characteristics except weight (P = 0.020) and body mass index (BMI) (P = 0.003). Patient's satisfaction was higher in 2 L PEG-CaO (P = 0.016) and 1 L PEG-CaO-Asc groups (P = 0·017). Patients' compliance was 67.5, 71.4, and 80.5% in 3 L PEG, 2 L PEG-CaO, and 1 L PEG-CaO-Asc groups (P = 0.014). Adequate bowel preparation rate was 75, 78.57, and 53.66% in 3 L PEG, 2 L PEG-CaO, and 1 L PEG-CaO-Asc groups (P = 0.021). There were no differences in terms of remaining outcomes.

Conclusions: Despite an increase in patients' satisfaction and compliance, 1 L PEG-CaO-Asc significantly decreased adequate bowel preparation rate. However, 2 L PEG-CaO improved the patients' satisfaction and compliance and increased adequate bowel preparation rate (Registration number, ChiCTR-IIR-17012418).

Can a 1-day clear liquid diet with a split -dose polyethylene glycol overcome conventional practice patterns during the preparation for screening colonoscopy?

BACKGROUND/AIMS

A successful screening colonoscopy is closely linked to the quality of a bowel preparation. In this study, we aimed to determine the impact of a 1-day clear liquid diet (CLD) compared to a 3-day combined diet (CMD) accompanied by a split-dose regimen of polyethylene glycol and electrolyte lavage solution (PEG-ELS) for screening colonoscopy.

MATERIALS AND METHODS

This was a prospective, randomized, endoscopist-blinded study. Patients referred for screening colonoscopy were randomized to four groups as a 1-day CLD+PEG-ELS vs. a 1-day CLD+sulfate free (SF)-PEG-ELS and a 3-day CMD+PEG-ELS vs. a 3-day CMD+SF-PEG-ELS. An assessment of the quality of colon cleaning, tolerability to the preparation, and symptoms related to the preparation were recorded.

RESULTS

A total of 506 patients were enrolled in this study. The quality of bowel preparation was significantly inferior in the CMD+PEG-ELS group than CLD+PEG-ELS (p=0.004) and CMD+SF-PEG-ELS groups (p=0.007). There were no statistical differences among the groups in terms of the polyp detection rate. With respect to an easy rating of diet following and the consumption of laxative, there were no significant differences among the four groups. Gastric fullness and nausea/vomiting were pointed out much more, especially in the SF-PEG-ELS users (p=0.008 and p=0.004, respectively).

CONCLUSION

A 1-day CLD was not inferior to a 3-day CMD for colonoscopy preparation in terms of bowel cleaning, the polyp detection rate, and patient tolerance.

Favorable outcomes of prepackaged low-residue diet on bowel preparation for colonoscopy: Endoscopist-blinded randomized controlled trial

BACKGROUND AND AIM

2 L polyethylene glycol plus an ascorbic acid (PEGA) is known to be as effective. However, 2 L polyethylene glycol-based regimens are often still difficult for patients to tolerate. Therefore, we conducted this study to evaluate the potential of 1 L PEGA with prepackaged low-residue diet (PLD) as an alternative to 2 L PEGA before colonoscopy.

METHODS

The subjects were randomly assigned to either of the two groups. The 2 L PEGA group received 2 L PEGA split regimen. The 1 L PEGA with PLD group received PLD on the day preceding colonoscopy and 1 L PEGA. All endoscopic procedures were performed by one physician who did not know patients allocation. Bowel preparation status were graded using Boston Bowel Preparation Score (BBPS). A questionnaire regarding tolerability and safety was administered. This trial is registered at ClinicalTrials.gov (NCT03329339).

RESULTS

A total of 173 patients completed the study (86 in the 2 L PEGA group and 87 in the 1 L PEGA with PLD group). Bowel preparation was adequate in 88.4% (76/86) of patients in the 2 L PEGA group and 93.1% of patients in the 1 L PEGA with PLD group (81/87, P = 0.28). The patients in the 1 L PEGA with PLD group had higher whole Boston Bowel Preparation Scale score (P = 0.02) and expressed more satisfaction and willingness to repeat the procedure (P < 0.01). There was no significant difference with respect to compliance or safety.

CONCLUSION

1 L PEGA with PLD showed equivalent efficacy, greater satisfaction, and more willingness to repeat compared with 2 L PEGA for bowel preparation.

Evaluation of the combined effect of factors influencing bowel preparation and adenoma detection rates in patients undergoing colonoscopy

Background

Colonoscopy is a commonly used modality for screening and surveillance of colorectal cancer (CRC). Therefore, it is essential to have adequate bowel preparation (prep) for the procedure which depends on type of bowel regimens, diet before colonoscopy and timing of the procedure.

Aims

The purpose of this study is to analyse the effect of multiple factors on adenoma detection rate (ADR) and prep quality of colonoscopy. This is the also the first study determining outcomes based on various combinations of diet, timing of the procedure and bowel prep regimens.

Methods

This is a retrospective single-centre observational study. Data about diet before procedure, bowel prepprep regimen and timing of the procedure was collected for patients coming for screening colonoscopy.

Results

Patients with split prep had higher good prep rates (73.8% vs 56.2%) and higher ADRs (34.2 % vs 29.9%) as compared with non-split prep. The good prep quality (65.8% vs 62.1%) and ADRs (31.9% vs 31.5%) were comparable in patients who received clear liquid diet as compared with low residue diet. The good results of bowel prep were obtained with split prep with either clear liquids or low residue diet irrespective of the timing of procedure. The poor prep was noticed in patients who underwent procedure in afternoon, with a low restrictive diet and non-split bowel regimen.

Conclusions

The current study adds to our knowledge about the combined effect of multiple variables affecting the bowel prep quality and ADR. It is imperative to opt for the best combination required for colonoscopy, as this will influence the effectiveness of colonoscopies regarding timely cancer detection and prevention.

Results of a Community-based, Randomized Study Comparing a Clear Liquid Diet With a Low-residue Diet Using a Magnesium Citrate Preparation for Screening and Surveillance Colonoscopies

BACKGROUND

Current bowel preparations for colonoscopy include a clear liquid diet (CLD) along with consumption of a laxative. This dietary restriction along with large volume bowel preparations are barriers to compliance and willingness among patients in scheduling screening examinations. The aim of our study was to compare the efficacy and tolerability of a low-volume split dose magnesium citrate bowel preparation in patients on a low-residue diet (LRD) with those on a CLD.

METHODS

In this single center, single blinded, randomized controlled trial, patients scheduled for outpatient colonoscopies were assigned to either a CLD or a LRD 1 day before the examination. Both groups received a split dose magnesium citrate preparation. The quality of the preparation was rated using the Boston Bowel Preparation Scale (BBPS). Patient satisfaction and side effects were evaluated using a questionnaire.

RESULTS

We were unable to detect a significant difference in the BBPS scores between the LRD and CLD groups (P=0.581). A significantly higher percentage of patients in the LRD group rated the diet as easy compared with the CLD group (P<0.001). Satisfaction scores were significantly higher in the LRD group, compared with the CLD group (P<0.001). The side effect profiles of both arms were similar.

CONCLUSIONS

There was no significant difference between LRD and CLD in patients using a magnesium citrate bowel preparation for screening and surveillance colonoscopies. Patient satisfaction scores were higher with a LRD compared with a CLD. We believe the LRD should be the recommended diet in patients using a standard bowel preparation for screening and surveillance colonoscopy.

Impact of diet restriction on bowel preparation for colonoscopy

Diet restriction is one of the difficult parts of bowel preparation for colonoscopy, and many patients do not follow instructions properly. Few studies have evaluated the impact of dietary restriction in real clinical setting. The aim of this study was to study the effect of diet control on bowel preparation with detailed investigation of unacceptable food list in order to reveal what kind of foods are most problematic in clinical practice.Prospective observational study was carried out at a university-affiliated hospital. Around 4 L polyethylene glycol solution was used for bowel preparation on the day of colonoscopy. Patients were allowed to have regular diet until lunch the day before colonoscopy and educated to control diet from 3 days before colonoscopy with information regarding an unacceptable foods list. Factors associated with inadequate bowel preparation were analyzed using univariate statistics and multivariate logistic regression analysis.Of the 245 patients included in the study, 68 patients (27.8%) followed the diet instructions. Fiber-rich vegetables were the most commonly taken unacceptable foods (N = 143, 58.4%). Inadequate bowel preparation (fair and poor by Aronchick scale) was 47.3%. In multivariate analysis, diabetes [odds ratio (OR) 2.878, 95% confidence interval (CI) 1.242-6.671], preparation to colonoscopy interval (OR 1.003, 95% CI 1.000-1.005) and consumption of foods disturbing bowel preparation (OR 2.142, 95% CI 1.108-4.140) were independent predictors of inadequate bowel preparation.We could identify substantially low compliance to diet instructions in real clinical practice. Consumption of any foods disturbing bowel preparation was significant factor predicting inadequate bowel preparation, even though we could not select specific food list compromising preparation significantly. Favorable bowel preparation was achieved in the subgroup compliant to diet restriction, suggesting that regular diet avoiding specific kinds of foods can be possible option for diet restriction before colonoscopy.

Research progress on patient comfort during bowel preparation

Bowel preparation is one of the key and necessary steps for preoperative preparations of multiple operations such as electronic colonoscopy, capsule endoscopy, barium X-ray, colorectal surgery, gynecology surgery, and urology surgery. Although better methods for bowel preparation have been explored continuously, patient intolerance still exists during the current bowel preparation process. Adverse reactions such as nausea and vomiting often occur, leading to poor comfort experience and affecting the patient's compliance and bowel preparation results. This article reviews the factors influencing patient comfort during bowel preparation and the corresponding interventions.

Clear Liquid Versus Low-fibre Diet in Bowel Cleansing for Colonoscopy in Children: A Randomized Trial

OBJECTIVES

In light of a paucity of data on the role of diet in colonoscopy preparation in paediatric population, the present study was designed to compare the effectiveness of clear liquid and low-fibre diets for breakfast and lunch on the day preceding colonoscopy in children.

METHODS

This prospective, randomised trial was conducted at the Department of Paediatric Gastroenterology and Nutrition in Warsaw, Poland. Eligible patients, referred for colonoscopies, were 6 to 18 years old. Patients were randomly divided into 2 groups: the first received a clear liquid diet and the second a low-fibre diet on the day before colonoscopy. In the afternoon, all participants were asked to drink polyethylene glycol with electrolytes at a dose of 66 mL/kg to a maximum of 4 L. The effectiveness of bowel cleansing was measured using the Boston Bowel Preparation Scale (BBPS). The preparation tolerance was assessed by parents and children using a visual analogue scale. Adverse effects were reported.

RESULTS

In total, 184 patients were enrolled. Of those, 96 received the clear liquid diet and 88-the low-fibre diet. The mean age of both groups was 15 years. There were no differences between the 2 study groups in age, weight, and sex, as well as in total BBPS score (BBPS ≥ 5 96.6% vs 95.1%, P = 0.5). The frequency of adverse effects was similar in both groups; nausea was the most common (P = 0.8).

CONCLUSIONS

Clear liquid and low-fibre diets administered to children the day before colonoscopy demonstrated similar bowel cleansing effectiveness.

Comparative efficacy of combination of 1 L polyethylene glycol, castor oil and ascorbic acid versus 2 L polyethylene glycol plus castor oil versus 3 L polyethylene glycol for colon cleansing before colonoscopy: Study protocol of a randomized, double-blind, single-center study

Colonoscopy has been regarded as an important method of early diagnosing and treating gastrointestinal lesions; however adequate bowel preparation is critical one of many factors needed for successful colonoscopy. Although several modified or novel regimes have been developed, desired quality of bowel preparation has not yet been generated. Scattered evidences revealed that castor oil may have potential of effectively cleansing colon. It is noted that, however, prospective trial of exploring the value of castor oil in preparing bowel before colonoscopy is lacking. The aims of this study are to test the hypotheses that low dose castor oil (30 mL) may enhance potential of polyethylene glycol (PEG) and combination of low castor oil and ascorbic acid may halve the volume of PEG.This is a randomized, double-blind (endoscopist and assessor), single center trial with three-arm design. We will randomly assign 282 adult patients (≥18 years but < 75 years), who are scheduled to undergo colonoscopy, to receive either 3 L PEG alone, 2 L PEG plus 30 mL castor oil or combination of 1 L PEG, 30 mL castor oil and 5 g ascorbic acid. The bowel preparation quality based on Boston Bowel Preparation Scale (BBPS) is the primary outcome. The secondary outcomes include the first defecation time, total number of defecation, time of cecal intubation, detection rate of polyp and adenoma, willing to repeat the same regime, tolerance to regime, and adverse events.The study protocol has been approved by the Clinical Research Ethics Committees of Chongqing University Cancer Hospital & Chongqing Cancer Institute & Chongqing Cancer Hospital & Chongqing Cancer Center (2017[107]). The results from this trial will be submitted for publication in peer-reviewed journals, and will be presented at national and international conferences.

A Customized Mobile Application in Colonoscopy Preparation: A Randomized Controlled Trial

OBJECTIVES

Adherence with diet and prescribed purgative is essential for proper cleansing with low-volume bowel preparations. The aim of this work was to assess the effect of a customized mobile application (App) on adherence and quality of bowel preparation.

METHODS

One hundred and sixty (160) eligible patients scheduled for elective colonoscopy were randomly assigned to paper (control) or App-based instructions. The preparation consisted of low-fiber diet for 2 days, clear fluids for one day and split-dose sodium picosulfate/magnesium citrate (SPS). Before colonoscopy, information was collected regarding adherence with, and utility of the provided instructions. The colonoscopists, blinded to assignment, graded bowel preparation using the Aronchick, Ottawa, and Chicago preparation scales. The primary endpoint was adherence with instructions. Quality of preparation was a secondary endpoint.

RESULTS

No difference in overall adherence or bowel cleanliness was observed between the study arms. Adherence was reported in 82.4% of App vs. 73.4% of controls (P=0.40). An adequate bowel preparation on the Aronchick scale was noted in 77.2 vs. 82.5%, respectively (P=0.68). Mean scores on the Ottawa and Chicago scales were also similar. Gender, age, time of colonoscopy, and BMI did not influence preparation or adherence. Compliance with the clear fluid diet component was noted in 94% of patients with BMI<30 vs. 77% with BMI≥30 (P<0.01). SPS was well tolerated by 81.9% of patients. The App was user-friendly and received higher overall rating in this respect than paper instructions (P<0.01).

CONCLUSIONS

SPS is well tolerated and effective for bowel cleansing regardless of instruction method. Customized smartphone applications are effective, well-accepted and could replace standard paper instructions for bowel preparation.ClinicalTrials.gov: NCT02410720.