This document is an update to the 2014 recommendations for optimizing the adequacy of bowel cleansing for colonoscopy from the US Multi-Society Task Force on Colorectal Cancer, which represents the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy. The US Multi-Society Task Force developed consensus statements and key clinical concepts addressing important aspects of bowel preparation for colonoscopy. The majority of consensus statements focus on individuals at average risk for inadequate bowel preparation. However, statements addressing individuals at risk for inadequate bowel preparation quality are also provided. The quality of a bowel preparation is defined as adequate when standard screening or surveillance intervals can be assigned based on the findings of the colonoscopy. We recommend the use of a split-dose bowel preparation regimen and suggest that a 2 L regimen may be sufficient. A same-day regimen is recommended as an acceptable alternative for individuals undergoing afternoon colonoscopy, but we suggest that a same-day regimen is an inferior alternative for individuals undergoing morning colonoscopy. We recommend limiting dietary restrictions to the day before a colonoscopy, relying on either clear liquids or low-fiber/low-residue diets for the early and midday meals. We suggest the adjunctive use of oral simethicone for bowel preparation before colonoscopy. Routine tracking of the rate of adequate bowel preparations at the level of individual endoscopists and at the level of the endoscopy unit is also recommended, with a target of >90% for both rates.

Bowel cleansing is a key element for a quality colonoscopy. Despite recent advances, not all predictors of successful cleansing are fully known. This post hoc analysis of an RCT aims to explore gender differences in bowel cleansing quality.

The "OVER" trial was a multicenter phase-4 RCT including 478 patients randomized 1:1 to receive split-dose 1L polyethylene glycol plus ascorbate (PEG+ASC) or 4L-PEG. In this post hoc analysis, multivariable logistic regression models were designed to assess predictors of cleansing success (CS) and adenoma detection rate (ADR) by gender.

Of the 478 randomized patients, 50.2% were males and 49.8% females.Overall, CS was comparable between females and males (87.1% vs 88.4, P = 0 .6), whereas CS in the right (95.7% vs 90.9, P = 0.049) and transverse colon (98.6% vs 93.9, P =0.011) was significantly higher in females.At multivariable regression analysis for CS outpatient setting (OR = 5.558) and higher withdrawal time (OR = 1.294) were independently associated with CS in females, whereas screening/surveillance indication (OR = 6.776) was independently associated with CS in males.At multivariable regression analysis for ADR, running time <5 hours (OR = 3.014) and higher withdrawal time (OR = 1.250) were independently associated with ADR in females, whereas older age (OR = 1.040) and higher withdrawal time (OR = 1.093) were independently associated with ADR in males.

This study showed different results in bowel preparation quality and different predictors of CS and ADR by gender. These findings suggest the need for further research to explore gender-specific approaches for bowel preparation.

This document is an update to the 2014 recommendations for optimizing the adequacy of bowel cleansing for colonoscopy from the US Multi-Society Task Force on Colorectal Cancer, which represents the American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy. The US Multi-Society Task Force developed consensus statements and key clinical concepts addressing important aspects of bowel preparation for colonoscopy. The majority of consensus statements focus on individuals at average risk for inadequate bowel preparation. However, statements addressing individuals at risk for inadequate bowel preparation quality are also provided. The quality of a bowel preparation is defined as adequate when standard screening or surveillance intervals can be assigned based on the findings of the colonoscopy. We recommend the use of a split-dose bowel preparation regimen and suggest that a 2 L regimen may be sufficient. A same-day regimen is recommended as an acceptable alternative for individuals undergoing afternoon colonoscopy, but we suggest that a same-day regimen is an inferior alternative for individuals undergoing morning colonoscopy. We recommend limiting dietary restrictions to the day before a colonoscopy, relying on either clear liquids or low-fiber/low-residue diets for the early and midday meals. We suggest the adjunctive use of oral simethicone for bowel preparation before colonoscopy. Routine tracking of the rate of adequate bowel preparations at the level of individual endoscopists and at the level of the endoscopy unit is also recommended, with a target of >90% for both rates.

Quality of gastrointestinal endoscopy is a major determinant of its effectiveness. Artificial intelligence (AI) has the potential to enhance quality monitoring and improve endoscopy outcomes. This article reviews the current literature on AI algorithms that have been developed for endoscopy quality assessment.

Colon hydrotherapy devices serve as a physiotherapeutic modality to manage colonic disorders by promoting intestinal peristalsis and enhancing gastrointestinal functionality. This study aims to assess and compare the effectiveness, safety, and tolerability of two remedial strategies for inadequate bowel preparation: colon hydrotherapy device enema and oral polyethylene glycol electrolyte powder.

A retrospective analysis was performed on 109 patients who failed to adequately prepare for colonoscopy. These patients received remedial bowel preparation on the same day as their procedure, with 55 undergoing colon hydrotherapy enema and 54 receiving oral polyethylene glycol electrolyte powder. Patient satisfaction and tolerance were evaluated through telephone follow-up. Key metrics included the Boston Bowel Preparation Scale scores, preparation time, incidence of adverse reactions, and patient tolerance and satisfaction.

No significant differences were observed in baseline characteristics between groups (P >  0.05). The Boston Bowel Preparation Scale scores for the entire colon were 7 (3) in the hydrotherapy group and 6.5 (1) in the oral group (z =  -2.075, P =  0.038). Notably, scores for the left colon were significantly higher in the hydrotherapy group [3 (1) vs. 2 (0), z =  -5.586, P <  0.001]. The hydrotherapy group also exhibited a shorter preparation time [80 (20) min vs. 92.5 (20) min, z =  -3.961, P <  0.001] and a lower incidence of adverse effects (36.4% vs. 88.9%, χ² =  32.035, P <  0.001). Patient satisfaction metrics, including re-selection rates and tolerance of side effects, were significantly higher in the hydrotherapy group.

The colon hydrotherapy device enema is an effective, efficient, and well-tolerated method for bowel cleansing, demonstrating a low incidence of adverse events. It is recommended as an effective and safe remedial therapy for patients with inadequate bowel preparation prior to colonoscopy.

Opinions about the impact of bowel preparation on the gut microbiota are divided. This study investigated the effects of different regimens on the gut microbiota post-bowel preparation and the differences in responses across different age groups.

This single-center, prospective, randomized, controlled clinical trial included 194 patients. Patients were categorized into two groups: one group receiving polyethylene glycol (n = 108) and one receiving sodium picosulfate (n = 86) for bowel preparation. Fecal samples were collected at baseline and on days 7 and 14 post-bowel preparation. The microbiota's diversity and composition were analyzed using 16S ribosomal RNA gene sequencing, followed by comparative analyses.

The gut microbiota's abundance and diversity in patients significantly decreased post-bowel preparation, which did not recover to the level of pre-bowel preparation on Day 14. When comparing different regimens, the polyethylene glycol and sodium picosulfate groups recovered faster in richness and diversity, respectively. Patients aged < 65 years had higher richness and diversity of the gut microbiota, whereas the microbiota structure in those aged ≥ 65 years returned to the baseline state faster. The structure of beta diversity is significantly altered and did not return in the short term. However, in the elderly population aged ≥ 65 years, it can rebound quickly. This study also identified a number of significantly altered bacterial genera.

Following the use of different bowel preparation regimens, the gut microbiota recovers in diverse ways, with older people over 65 experiencing a faster recovery of the microbial structure.

The quality of a colonoscopy is heavily reliant on the effectiveness of bowel cleansing. Various cleansing solutions are currently available, but their comparative efficacy remains uncertain. This systematic review and network meta-analysis aims to compare the performance of different bowel preparations for colonoscopy.

MEDLINE, Embase, Scopus, and the Cochrane Library were systematically searched for randomized controlled trials (RCTs) comparing the efficacy of different bowel preparations. The primary outcome was cleansing success (CS), and the secondary outcome was adenoma detection rate (ADR).

On network meta-analysis for CS (22 RCTs, 7179 patients, 14 bowel preparations), 2 L PEG + simethicone (RR = 1.25 [95 %CI = 1.13-1.37]), 2 L PEG + lactulose (RR = 1.22 [95 %CI = 1.10-1.38]) and 1 L PEG + ascorbate (ASC) (RR = 1.03 [95 %CI = 1.01-1.06]) were significantly superior to 2 L PEG + ASC. Overall, 2 L PEG + lactulose resulted as the best product (SUCRA 0.94), followed by 2 L PEG + simethicone (SUCRA 0.93). On network meta-analysis for ADR (17 RCTs, 6639 patients, 11 bowel preparations), only 2 L PEG + simethicone (RR = 1.60 [95 %CI = 1.05-2.43]) resulted significantly superior to 2 L PEG + ASC.

2 L PEG + simethicone, 2 L PEG + lactulose, and 1 L PEG + ASC seemed to provide high rates of CS, albeit only 2 L PEG + simethicone was associated with significantly higher ADR. Consequently, these products should be preferred for bowel preparation of colonoscopy. Further randomized studies with adequate sample sizes are needed for a more accurate comparison of these products on ADR.

Polyethylene glycol electrolyte solution (PEG-ELS) is the standard for bowel preparation but often suffers from poor patient compliance and tolerability due to its high-volume requirement. This prospective, single-blinded, non-inferiority, randomized control trial aims to investigate the efficacy and safety of a lactulose-based regimen as an alternative for bowel preparation.

Two hundred nine patients were randomly allocated to receive either a combination regimen consisting of 133.4 g lactulose in 200 mL, 800 mL carbohydrate-containing clear liquid, 2L additional water, and 5 g simethicone (n = 104) or 3L PEG-ELS with 5 g simethicone (n = 105), both administered in a split-dose format. The primary outcome was the rate of adequate bowel preparation, measured by the Boston bowel preparation score (BBPS). Adequate bowel preparation was defined as a BBPS score of 2 or 3 in all colon segments. Secondary outcomes included the percentage of high-quality bowel preparation (defining as a total BBPS score of 8 or 9), polyp detection rate (defining as the percentage of procedures where at least one polyp was detected), willingness to repeat the bowel preparation, adverse events, and changes in blood glucose and electrolyte levels.

The rate of adequate bowel preparation (96.2% vs. 97.1%, p = 0.691), the percentage of high-quality preparation (62.5% vs. 66.7%, p = 0.529), average total BBPS scores (p = 0.607), polyp detection rates (66.3% vs. 77.1%, p = 0.083), and tolerability and acceptability outcomes, including satisfaction (p = 0.729) and willingness to repeat preparation (p = 0.744), were not statistically different between the two arms. Adverse events and changes in blood glucose and electrolytes showed no significant differences (all p > 0.05).

The combination of oral lactulose and carbohydrate-containing clear fluids was non-inferior to 3L PEG-ELS for bowel preparation adequacy and polyp detection, without statistically significant differences in terms of tolerability and safety.

Bowel preparation represents a significant issue to high-quality colonoscopy. Oral mannitol requires a single dose, is of low volume, and has a pleasant taste and rapid action.

This SATISFACTION study compared single-dose (same day) oral mannitol 100 g/750 mL with standard split-dose PEG-ASC2 L (MoviPrep®).

The primary endpoint was the proportion of patients with adequate bowel cleansing. Secondary endpoints included efficacy (adenoma detection rate, caecal intubation rate, time of evacuation), safety (intestinal gases concentration, haemato-chemical parameters, adverse events), and patient satisfaction.

The study included 703 patients (352 treated with mannitol and 351 with PEG-ASC). Mannitol was not inferior to PEG-ASC for the primary endpoint (91.1 % and 95.5 %, respectively; p-value for the non-inferiority =0.0131). There was no significant difference for secondary efficacy endpoints. The acceptability profile was significantly better in the mannitol group for ease of use, taste, and willingness to reuse (p < 0.0001 for all). The concentration of intestinal gases (H2, CH4) was similar between groups and well below those potentially critical.

The SATISFACTION study indicated that low-volume, single-dose mannitol may satisfy an unmet clinical need since it was more acceptable to the patient and not inferior to the split-dose PEG-ASC for bowel cleansing efficacy.

There is robust evidence to indicate a strong correlation between the bowel preparation status and adenoma detection rate (ADR), which directly impacts the incidence and mortality rate of postcolonoscopy colorectal cancer. Therefore, improving bowel preparation has been of increasing interest. In Japan, commercially available bowel preparation agents include polyethylene glycol, oral sodium sulfate, sodium picosulfate-magnesium citrate, magnesium citrate, and oral sodium phosphate; each has its own strengths and limitations. The timing of administration can also influence the efficacy of bowel preparation and patient tolerability. Furthermore, meta-analyses have suggested predictive factors for inadequate bowel preparation. A detailed understanding of these factors could contribute to reducing the need for repeat colonoscopy within 1 year, as recommended for patients with inadequate bowel preparation. Recent advancements, such as oral sulfate tablets, present promising alternatives with higher patient satisfaction and ADRs than traditional methods. Achieving optimal bowel preparation requires enhanced instructions, individualized regimens, and a comprehensive understanding of patient backgrounds and the characteristics of various bowel preparation agents. This article provides a concise overview of the current status and advancements in bowel preparation for enhancing the quality and safety of colonoscopy.

The quality of bowel preparation is an important factor in the success of colonoscopy. However, multiple influencing factors that function together can lead to inadequate bowel preparation. The main objective of this study was to explore the specific factors that affect the quality of bowel preparation, with the goal of deriving and validating a predictive model for inadequate bowel preparation in Chinese outpatients. A prospective observational study. We conducted a prospective study in a tertiary hospital in Zhejiang Province that included elective colonoscopy outpatients treated between December 15, 2022 and August 12, 2023. Clinical data related to the patient characteristics and patient bowel preparation were collected to analyze the risk factors of inadequate bowel preparation in outpatients. The quality of bowel preparation was assessed by using the Boston bowel preparation scale (BBPS). Inadequate bowel preparation was defined as a total BBPS score of < 6 or any segment score of < 2. The predictive model was constructed based on multivariate logistic regression, and the discrimination and calibration of the prediction model were evaluated via internal and external validation; additionally, a clinical decision curve was drawn to evaluate the clinical utility of the model. A total of 1314 patients were included from December 15, 2022 through May 31, 2023 (derivation cohort, n = 1035) and from June 1 through August 12, 2023 (external validation cohort, n = 279). Inadequate bowel preparation occurred in 260 of 1035 patients in the derivation cohort (25.1%). Multivariate analysis identified that male sex (OR = 1.690, 95% CI: 1.242-2.300), diabetes (OR = 1.769, 95% CI: 1.059-2.954), constipation (OR = 2.375, 95% CI: 1.560-3.617), history of colorectal surgery (OR = 2.915, 95% CI: 1.455-5.840), a high fiber diet used at 24 h before examination (OR = 2.662, 95% CI: 1.636-4.334) and the time interval from the end of the bowel preparation to the start of the colonoscopy (PC) >5 h (OR = 2.471, 95% CI: 1.814-3.366) were independent risk factors. We derived a model to identify patients with inadequate cleansing by using data from patients in the derivation cohort and tested it in the validation cohort. The area under the curve (AUC) was 0.704 (95% CI: 0.667-0.741), with a calibration value of p = 0.632 in the derivation cohort. Bootstrap cross-validation showed a good model calibration condition. For the validation cohort, the AUC was 0.704 (95% CI: 0.628-0.779), and the calibration value was p = 0.376. We identified the influencing factors of outpatient bowel cleansing that are associated with patient clinical characteristics and bowel preparation-related behaviors. A model was constructed and validated to identify patients who were at high risk of inadequate bowel preparation by using six simple variables, which included male sex, diabetes, constipation, history of colorectal surgery, a high fiber diet used at 24 h prior to examination, and PC > 5 h. The clinical decision curve showed that the constructed prediction model has some clinical utility based on results from the derivation cohort and validation cohort.

Colonoscopy is widely used as a diagnostic and preventive procedure for colorectal diseases. The most recent guidelines advocate the use of a low-residue diet (LRD) for bowel preparation before colonoscopy. LRD duration varies considerably, with recommended 1-day and multiple-day regimens in clinical practice.

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched multiple databases for randomized controlled trials (RCTs) and analyzed the outcomes using a fixed-effects model.

Six RCTs with 2,469 subjects were included in this study. The rates of adequate bowel preparation for 1-day and >1-day were 87.2% and 87.1%, respectively. No statistically significant differences were observed between the 1-day and >1-day LRD in adequate bowel preparation (odds ratio [OR], 1.03; 95% confidence interval [CI], 0.76-1.41; p=0.84; I2=0%), polyp detection rate (OR, 0.91; 95% CI, 0.76-1.09; p=0.29; I2=16%), adenoma detection rate (OR, 0.87; 95% CI, 0.71-1.08; p=0.21; I2=0%), and withdrawal time (mean difference, -0.01; 95% CI, -0.25 to 0.24; p=0.97; I2=63%).

The efficacy of 1-day and multiple-day LRD is comparable in achieving satisfactory bowel preparation, highlighting their similar impact on the detection of polyps and adenomas during colonoscopy.

Suboptimal bowel preparation adversely affects colonoscopy quality, increases healthcare costs, and prolongs waiting time. The primary contributing factors include poor tolerance to the preparation solutions, noncompliance with prescribed instructions, and suboptimal efficacy of the bowel cleansing solution itself.

This review examined the predictive factors associated with suboptimal bowel preparation and discussed interventions aimed at improving bowel cleansing. It also provides evidence-based practical algorithms supplemented by insights from our own clinical experience. Relevant topics were reviewed using resources from the PubMed database.

Although current bowel preparation protocols are effective for the majority of patients, a significant proportion still present challenges for optimal preparation. These patients may benefit from personalized strategies tailored to the specific causes of preparation failure. Conducting a thorough interview is crucial for identifying the reasons for failure, particularly in patients who have previously experienced suboptimal preparation during colonoscopy. In colonoscopy-naïve patients, it is essential to assess the risk of suboptimal preparation. In both cases, interventions should be customized to either address the identified causes in the former group or employ preventive strategies to reduce the likelihood of failure in the latter.

Three liters of polyethylene glycol administered in a split dose is a commonly recommended regimen for bowel preparation before colonoscopy.

The aim of this study was to compare the quality and tolerability of low-dose (2 L) polyethylene glycol combined with linaclotide (2 L+L) versus the 3 L polyethylene glycol (PEG) bowel preparation regimen.

A noninferiority, prospective, multicenter, randomized controlled trial.

In this noninferiority, prospective, multicenter, randomized controlled study, patients scheduled for colonoscopy were enrolled and randomized to receive a 3 L PEG or 2L PEG+L regimen. The quality of bowel preparation and patients' discomfort was assessed.

Over 12 months, 458 patients were randomized into 3 L PEG and 2 L+L groups. The primary endpoints showed that the 2 L+L regimen was superior to the 3L PEG regimen in overall bowel cleansing scores (Ottawa Bowel Preparation Scale: 3.3 ± 2.1 vs 3.7 ± 2.1, p = 0.021), but no significant difference in adequate bowel preparation rate between the two groups according to the OBPS score (97% vs 97.4%, p = 0.791). Before colonoscopy, patients in the 2 L +L regimen group had lower bloating scores (0.5 (0, 2) vs 1 (0, 3), p = 0.013), discomfort scores (1 (0, 2) vs 1 (0, 3), p = 0.006), and intolerability scores (1 (0, 3) vs 2 (0, 4), p = 0.016) than did those in the 3L PEG group.

Two liters of polyethylene glycol combined with linaclotide may be an alternative regimen to 3 L of PEG taken in split doses for bowel preparation before colonoscopy.

ChiCTR2100041992.

The performance of bowel preparation (BP) in patients with Crohn's disease (CD) is unknown.

To evaluate the operating properties of instruments used to assess BP quality in patients with CD.

We used the Boston Bowel Preparation Scale, modified Boston Bowel Preparation Scale, Harefield Cleansing Scale, Food and Drug Administration Bowel Cleansing Assessment Scale (BCAS), and a 100-mm visual analogue scale of bowel cleanliness to assess BP quality in 50 videos from 40 patients with CD. We assessed endoscopic activity with the Simple Endoscopic Score for CD (SES-CD). Assessments were on endoscope insertion and withdrawal. Reliability was quantified using the intraclass correlation coefficient (ICC). We assessed validity by within-patient correlation between instruments and the visual analogue scale using mixed-effect models. The correlation between BP quality and SES-SD scores was assessed using Spearman's rho.

Inter- and intra-rater reliability for all BP quality instruments was substantial (ICC ≥0.61) except for the Food and Drug Administration BCAS on insertion (inter-rater reliability ICC ≥0.41). The visual analogue scale had substantial inter- and almost perfect (ICC ≥0.81) intra-rater reliability. Correlation coefficients for the validity of the instruments exceeded 0.58. BP quality and endoscopic disease activity scores in the colon were negatively correlated.

Most existing instruments reliably assess BP quality in patients with CD. These results support the use of these instruments in clinical practice, provide a framework for scoring BP quality in CD clinical trials, and support evaluation of novel BP agents in patients with CD.

Artificial intelligence (AI) has emerged as a promising tool for detecting and characterizing colorectal polyps during colonoscopy, offering potential enhancements in traditional colonoscopy procedures to improve outcomes in patients with inadequate bowel preparation.

This study aimed to assess the impact of an AI tool on computer-aided detection (CADe) assistance during colonoscopy in this population.

This case-control study utilized propensity score matching (PSM) for age, sex, race, and colonoscopy indication to analyze a database of patients who underwent colonoscopy at a single tertiary referral center between 2017 and 2023. Patients were excluded if the procedure was incomplete or aborted owing to poor preparation. The patients were categorized based on the use of AI during colonoscopy. Data on patient demographics and colonoscopy performance metrics were collected. Univariate and multivariate logistic regression models were used to compare the groups.

After PSM patients with adequately prepped colonoscopies (n = 1466), the likelihood of detecting hyperplastic polyps (OR = 2.0, 95%CI 1.7-2.5, p < 0.001), adenomas (OR = 1.47, 95%CI 1.19-1.81, p < 0.001), and sessile serrated polyps (OR = 1.90, 95%CI 1.20-3.03, p = 0.007) significantly increased with the inclusion of CADe. In inadequately prepped patients (n = 160), CADe exhibited a more pronounced impact on the polyp detection rate (OR = 4.34, 95%CI 1.6-6.16, p = 0.049) and adenomas (OR = 2.9, 95%CI 2.20-8.57, p < 0.001), with a marginal increase in withdrawal and procedure times.

This study highlights the significant improvement in detecting diminutive polyps (< 5 mm) and sessile polyps using CADe, although notably, this benefit was only seen in patients with adequate bowel preparation. In conclusion, the integration of AI in colonoscopy, driven by artificial intelligence, promises to significantly enhance lesion detection and diagnosis, revolutionize the procedure's effectiveness, and improve patient outcomes.

Background Colorectal cancer (CRC) remains a significant public health challenge. Patients having abnormal faecal immunochemical test (FIT) results are offered a colonoscopy. The effectiveness of colonoscopies can, however, often be challenged by the occurrence of missed polyps. This study aims to assess the rate of significant missed polyps in the Bowel Cancer Screening Programme (BCSP) in the UK. Methods A retrospective analysis of BSCP screening data in the Cheshire region in the UK from 2020 to March 2023 was conducted. A significant polyp was defined as a polyp ≥ 10mm. The inclusion criteria included patients (age range: 54-74 years) who had had an index colonoscopy followed by site checks, repeats, or planned polypectomies. Results Out of 2,759 index colonoscopies, 261 (9.5%) met our criteria, and 23 (8.8%) of these had significant polyps. Of the 261, the missed polyp rate was 30% (453/1531 polyps). The overall significant missed polyp rate was 1.6% (24/1531). Of the missed polyps, 5% (24/453) were significant polyps. The majority (71%) of the significant polyps were found on the left of the colon. Men had a higher missed polyp rate (22%) compared to women (7%) (relative risk (RR) = 2.56, 95% CI: 2.1-3.13, p<0.0001). They also had a higher significant missed polyp rate (1.1%) compared to women (0.4%) (RR = 2.41, 95% CI: 1-5.8, p<0.05). A total of 50% of the bowel prep at index colonoscopy was rated as 'adequate/fair' and 79% of the bowel prep at the discovery of the significant polyp was rated as either 'excellent' or 'good' (odds ratio (OR) = 3.8, 95% CI: 1.07-13.5, p<0.05); 92% (22/24) of the significant polyps found were either tubular adenoma (TA) low-grade dysplasia (LGD) or tubular villous adenoma (TVA) LGD, and none were found to be cancerous. Conclusions Almost a third of all polyps detected were missed, and one in 20 of these were significant polyps, putting these patients in the high-risk group for CRC. Improving bowel preparation and monitoring patients with multiple polyps could reduce the rate of missed polyps.

Information on effective bowel preparation (BP) methods for patients with constipation is limited. We recently reported the efficacy of 1 L polyethylene glycol plus ascorbic acid (PEG-Asc) combined with senna for BP; however, this regimen was insufficient in patients with constipation. We hypothesized that the addition of linaclotide, which is approved for the treatment of chronic constipation, to 1 L PEG-Asc would yield results superior to those of senna in patients with constipation.

This was a retrospective, single-center study that included outpatients with constipation who underwent BP prior to colonoscopy between March and December 2019 (receiving 1 L PEG-Asc with 24 mg senna) and between January and October 2020 (receiving 1 L PEG-Asc with 500 mg linaclotide).

A total of 543 patients with constipation were included, of whom 269 received linaclotide and 274 received senna. The rate of inadequate BP was significantly lower (11% vs 20%, p < 0.01) and the adenoma detection rate was significantly higher (54% vs 45%, p = 0.04) in the linaclotide group than in the senna group. Multivariate analysis revealed that the linaclotide regimen significantly reduced the risk of inadequate BP (odds ratio = 0.36, 95% confidence interval = 0.21-0.60, p < 0.01).

The linaclotide regimen significantly increased BP efficacy and the adenoma detection rate compared with the senna regimen without reducing tolerability and is therefore a promising new option for BP in patients with constipation.

Accurate bowel preparation assessment is essential for determining colonoscopy screening intervals. Patients with suboptimal bowel preparation are at a high risk of missing >5 mm adenomas and should undergo an early repeat colonoscopy. In this study, we used artificial intelligence (AI) to evaluate bowel preparation and validated the ability of the system to accurately identify patients who are at high risk of having >5 mm adenomas missed due to inadequate bowel preparation.

This prospective, single-center, observational study was conducted at the Eighth Affiliated Hospital, Sun Yat-sen University, from October 8, 2021, to November 9, 2022. Eligible patients who underwent screening colonoscopy were consecutively enrolled. The AI assessed bowel preparation using the e-Boston Bowel Preparation Scale (e-BBPS) while endoscopists made evaluations using BBPS. If both BBPS and e-BBPS deemed preparation adequate, the patient immediately underwent a second colonoscopy; otherwise, the patient underwent bowel re-cleansing before the second colonoscopy.

Among the 393 patients, 72 adenomas >5 mm in size were detected; 27 adenomas >5 mm in size were missed. In unqualified-AI patients, the >5 mm adenoma miss rate (AMR) was significantly higher than in qualified-AI patients (35.71% vs 13.19% [P = .0056]; odds ratio [OR], .2734 [95% CI, .1139-.6565]), as were the AMR (50.89% vs 20.79% [P < .001]; OR, .2532 [95% CI, .1583-.4052]) and >5 mm polyp miss rate (35.82% vs 19.48% [P = .0152]; OR, .4335 [95% CI, .2288-.8213]).

This study confirmed that patients classified as inadequate by AI exhibited an unacceptable >5 mm AMR, providing key evidence for implementing AI in guiding bowel re-cleansing and potentially standardizing future colonoscopy screening. (Clinical trial registration number: NCT05145712.).

This study aimed to elucidate the effects of propofol plus adjuvants on postoperative cognitive dysfunction (POCD) and patient satisfaction.

Studies published up to September 2023 on the Chinese National Knowledge Infrastructure (CNKI), Wanfang Data, Sinomed, PubMed, Embase, Cochrane Library, Web of Science, and Clinictrials.gov websites were searched. Binary summary of results was used for meta-analyses.

We included 18 studies (2691 patients). The combined sedation did not affect the processing speed (ES = 0.02, 95%CI: -0.01, 0.04; I2 = 79.3%, p < 0.001), attention (ES = 0.02, 95%CI: -0.02, 0.05; I2 = 95.0%, p < 0.001), nor working memory (ES = 0.02, 95%CI: -0.03, 0.06; I2 = 94.4%, p < 0.001) in CogState brief battery tool. A significant effect of combined sedation was observed in the domain of visual learning in CogState tool (ES = -0.03, 95%CI: -0.04, -0.02; I2 = 15.8%, p = 0.306). The TDT (ES = 4.96, 95%CI: 2.92, 7.00) indicates that combined sedation would increase error rates in the tests of cognitive function. The DSST (ES = 0.16, 95% CI: -0.44, 0.75) shown that combined sedation does not affect cognitive function. In addition, an insignificant difference in patient satisfaction between combined sedation and propofol alone was observed (ES = -0.03, 95%CI: -0.09, 0.02).

The available evidence suggests that propofol combined with adjuvants may affect POCD but not patient satisfaction.

INPLASY2023110092.

The incidence and mortality of colorectal cancer (CRC) have decreased through regular screening colonoscopy, surveillance, and endoscopic treatment. However, CRC can still be diagnosed after negative colonoscopy. Such CRC is called interval CRC and accounts for 1.8-9.0% of all CRC cases. Most cases of interval CRC originate from missed lesions and incompletely resected lesions. Interval CRC can be minimized by improving the quality of colonoscopy. This has led to a growing interest in and demand for high-quality colonoscopy. It is important to reduce the risk of CRC and its associated mortality by improving the quality of colonoscopy. In this review article, we provide an overview of colonoscopy quality indicators, including bowel preparation adequacy, the cecal intubation rate, the adenoma detection rate, the colonoscopy withdrawal time, appropriate polypectomy, and complication of the procedure. Because colonoscopy is a highly endoscopist-dependent procedure, colonoscopists should be well-acquainted with quality indicators and strive to apply them in daily clinical practice for the prevention of CRC.

The effectiveness of colonoscopy is limited by the adequacy of bowel preparation. Nurses are essential in providing bowel cleansing agents and instructions for hospitalized patients before colonoscopy. This study aims to assess and improve the knowledge of nurses on bowel preparation for inpatient colonoscopy. Participants were asked to complete the survey before and after completing an educational module. The module and survey questions were placed in the NetLearning environment of the hospital intranet. A minimum post-test score of 80% was required to pass the course. A total of 1,107 nurses participated in the survey. Overall, the average score improved from 87% to 93% after the module (p < .0495). Knowledge of the different ways of consuming bowel cleansing agents improved from 54.3% to 83.6% (p = .0001). Only 56.2% of nurses knew how to carry out a split-dose bowel preparation regimen, which increased to 80.1% after the educational module (p = .0001). Nurses' knowledge about the different ways of consuming bowel cleansing agents before colonoscopy and the split-dose regimen is inadequate. A simple online educational module significantly improved the knowledge of nurses on bowel preparation for colonoscopy.

The present research was carried out to determine the impact of informing patients who would undergo a colonoscopy via short messaging service (SMS) on the procedure quality and satisfaction.

The study was designed as a randomized controlled experimental and single-blind.

The study was completed with 170 patients (87 in the control group and 83 in the intervention group). Verbal and written information about bowel preparation was provided to all patients at the first appointment. Additionally, a total of nine informative SMS, including the time of colonoscopy, dietary restrictions to be followed, purgative drugs to be used, and the time of taking the drugs, were sent to the patients in the intervention group starting 2 days before the procedure. Data were collected using a patient questionnaire, Boston Bowel Preparation Scale (BBPS), and postcolonoscopy follow-up form.

The mean score of each colon segment and the total BBPS mean score of the patients in the intervention group were higher compared to the control group, and the difference between them was statistically significant. The percentage of patients with adequate bowel preparation was significantly higher in the intervention group (84.3%) in comparison with the control group (71.3%). The intervention group had high compliance with a clear diet, enema application, and oral medication intake (P < .05). The cecum was reached in 85.5% of the intervention group. The majority of the patients (89.2%) in the intervention group reported that the information provided via SMS was adequate, and 91.6% were satisfied with the information provided by SMS.

The study shows that, in addition to written and verbal information provided before colonoscopy, SMS information positively impacts the quality of patients' bowel preparation, increases their compliance with the preparation instructions, the rate of reaching the cecum, and their satisfaction. Patient education with this practice can help ensure adequate bowel preparation quality and increase patient comfort in the colonoscopy procedure.

Adenoma detection rate (ADR) is challenging to measure, given its dependency on pathology reporting. Polyp detection rate (PDR) (percentage of screening colonoscopies detecting a polyp) is a proposed alternative to overcome this issue. Overall PDR from all colonoscopies is a relatively novel concept, with no large-scale studies comparing overall PDR with screening-only PDR. The aim of the study was to compare PDR from screening, surveillance, and diagnostic indications with overall PDR and evaluate any correlation between individual endoscopist PDR by indication to determine if overall PDR can be a valuable surrogate for screening PDR. Our study analyzed a prospectively collected national endoscopy database maintained by the National Institute of Health from 2009 to 2014. Out of 354,505 colonoscopies performed between 2009-2014, 298,920 (n = 110,794 average-risk screening, n = 83,556 average-risk surveillance, n = 104,770 diagnostic) met inclusion criteria. The median screening PDR was 25.45 (IQR 13.15-39.60), comparable with the median overall PDR of 24.01 (IQR 11.46-35.86, p = 0.21). Median surveillance PDR was higher at 33.73 (IQR 16.92-47.01), and median diagnostic PDR was lower at 19.35 (IQR 9.66-29.17), compared with median overall PDR 24.01 (IQR 11.46-35.86; p < 0.01). The overall PDR showed excellent concordance with screening, surveillance, and diagnostic PDR (r > 0.85, p < 0.01, 2-tailed). The overall PDR is a reliable and pragmatic surrogate for screening PDR and can be measured in real time, irrespective of colonoscopy indication.

Patients' perception of their bowel cleansing quality may guide rescue cleansing strategies before colonoscopy. The main aim of this study was to train and validate a convolutional neural network (CNN) for classifying rectal effluent during bowel preparation intake as "adequate" or "inadequate" cleansing before colonoscopy.

Patients referred for outpatient colonoscopy were asked to provide images of their rectal effluent during the bowel preparation process. The images were categorized as adequate or inadequate cleansing based on a predefined 4-picture quality scale. A total of 1203 images were collected from 660 patients. The initial dataset (799 images), was split into a training set (80%) and a validation set (20%). The second dataset (404 images) was used to develop a second test of the CNN accuracy. Afterward, CNN prediction was prospectively compared with the Boston Bowel Preparation Scale (BBPS) in 200 additional patients who provided a picture of their last rectal effluent.

On the initial dataset, a global accuracy of 97.49%, a sensitivity of 98.17% and a specificity of 96.66% were obtained using the CNN model. On the second dataset, an accuracy of 95%, a sensitivity of 99.60% and a specificity of 87.41% were obtained. The results from the CNN model were significantly associated with those from the BBPS (P<0.001), and 77.78% of the patients with poor bowel preparation were correctly classified.

The designed CNN is capable of classifying "adequate cleansing" and "inadequate cleansing" images with high accuracy.

Although studies have shown that the quality of bowel preparation with low-residue diet (LRD) is as effective as that of clear fluid diet (CLD), there is currently no consensus on how long an LRD should last. The aim of this study was to compare a 1-day versus 3-day LRD on bowel preparation before colonoscopy.

A systematic review search was conducted in MEDLINE/PubMed, EMBASE, Web of Science, and Cochrane database from inception to April 2023. We identified randomized controlled trials (RCTs) that compared 1-day with 3-day LRD bowel cleansing regiments for patients undergoing colonoscopy. The rate of adequate bowel preparation, polyp detection rate, adenoma detection rate, tolerability, willingness to repeat preparation, and adverse events were estimated using odds ratios (OR) and 95% confidence interval (CI). We also performed meta-analysis to identify risk factors and predictors of inadequate preparation.

Four studies published between 2019 and 2023 with 1927 participants were included. The present meta-analysis suggested that 1-day LRD was comparable with 3-day LRD for adequate bowel preparation (OR 0.89; 95% CI, 0.65-1.21; P = 0.45; I2 = 0%; P = 0.52). The polyp detection rate (OR 0.94; 95% CI, 0.77-1.14; P = 0.52; I2 = 23%; P = 0.27) and adenoma detection rate (OR 0.87; 95% CI, 0.71-1.08; P = 0.21; I2 = 0%; P = 0.52) were similar between the groups. There were significantly higher odds of tolerability in patients consuming 1-day LRD compared with 3-day LRD (OR 1.64; 95% CI, 1.13-2.39; P < 0.01; I2 = 47%; P = 0.15). In addition, constipation was identified as the independent predictor of inadequate preparation (OR 1.98; 95% CI, 1.27-3.11; P < 0.01; I2 = 0%; P = 0.46).

The present study demonstrated that a 1-day LRD was as effective as a 3-day CLD in the quality of bowel preparation before colonoscopy and significantly improved tolerability of patients. In addition, constipation is an independent risk factor of poor bowel preparation, and the duration of LRD in patients with constipation still needs further clinical trials.

We investigated the clinical practice patterns of post-polypectomy colonoscopic surveillance among Korean endoscopists.

In a web-based survey conducted between September and November 2021, participants were asked about their preferred surveillance intervals and the patient age at which surveillance was discontinued. Adherence to the recent guidelines of the U.S. Multi-Society Task Force on Colorectal Cancer (USMSTF) was also analyzed.

In total, 196 endoscopists completed the survey. The most preferred first surveillance intervals were: a 5-year interval after the removal of 1-2 tubular adenomas < 10 mm; a 3-year interval after the removal of 3-10 tubular adenomas < 10 mm, adenomas ≥ 10 mm, tubulovillous or villous adenomas, ≤ 20 hyperplastic polyps < 10 mm, 1-4 sessile serrated lesions (SSLs) < 10 mm, hyperplastic polyps or SSLs ≥ 10 mm, and traditional serrated adenomas; and a 1-year interval after the removal of adenomas with highgrade dysplasia, >10 adenomas, 5-10 SSLs, and SSLs with dysplasia. In piecemeal resections of large polyps ( > 20 mm), surveillance colonoscopy was mostly preferred after 1 year for adenomas and 6 months for SSLs. The mean USMSTF guideline adherence rate was 30.7%. The largest proportion of respondents (40.8%-55.1%) discontinued the surveillance at the patient age of 80-84 years.

A significant discrepancy was observed between the preferred post-polypectomy surveillance intervals and recent international guidelines. Individualized measures are required to increase adherence to the guidelines.

Colorectal cancer (CRC) is the second leading cause of cancer death. Screening has been proven to reduce both cancer incidence and cancer-related mortality. Various screening tests are available, each with their own advantages and disadvantages and varying levels of evidence to support their use. Clinicians should offer CRC screening to average-risk persons aged 50 to 75 years; starting screening at age 45 years remains controversial. Screening may be beneficial in select persons aged 76 to 85 years, based on their overall health and screening history. Offering a choice of screening tests or sequentially offering an alternate test for those who do not complete screening can significantly increase participation.

An easy-to-use preparation-related model (PRM) predicting inadequate bowel preparation (BP) was developed and proved superior to traditional models in our previous study. Here we aimed to investigate whether PRM-based individualized intervention can improve BP adequacy.

Patients undergoing morning colonoscopy were prospectively enrolled in 5 endoscopic centers in China. After standard BP of split-dose polyethylene glycol (PEG) was completed, patients were randomized (1:1) to the individualized group or standard group. High-risk patients predicted by PRM score ≥3 were instructed to drink an additional 1.5 L PEG in the individualized group while not in standard group. The primary endpoint was the rate of adequate BP, defined by segmental Boston bowel preparation scale ≥2. Secondary outcomes included adenoma detection rate (ADR) and adverse events.

900 patients were randomly allocated to the individualized group (n = 449) and the control (n = 451). Baseline characteristics were similar between the two groups. The rates of high-risk patients were 19.6 % in individualized group and 19.7 % in standard group. In intention-to-treat analysis, adequate BP was 91.8 % in individualized group and 84.7 % in the standard group (p = 0.001). Among high-risk patients, adequate BP rate was 94.3 % in individualized group and 49.3 % in standard group (p < 0.001), and ADR were 40.9 % vs 16.9 %, respectively (p < 0.001). No significant differences were found regarding the adverse events and willingness to repeat BP (all p >0.05).

The individualized intervention using an additional dose of PEG to high-risk patients predicted by PRM, significantly improved BP quality. The intervention significantly improved ADR in high-risk patients. (ClinicalTrials.gov number: NCT04434625).

Sodium picosulfate (SP)/magnesium citrate (MC) and polyethylene glycol (PEG) plus ascorbic acid are recommended by Western guidelines as laxative solutions for bowel preparation. Clinically, SP/MC has a slower post-dose defaecation response than PEG and is perceived as less cleansing; therefore, it is not currently used for major bowel cancer screening preparation. The standard formulation for bowel preparation is PEG; however, a large dose is required, and it has a distinctive flavour that is considered unpleasant. SP/MC requires a small dose and ensures fluid intake because it is administered in another beverage. Therefore, clinical trials have shown that SP/MC is superior to PEG in terms of acceptability. We aim to compare the novel bowel cleansing method (test group) comprising SP/MC with elobixibat hydrate and the standard bowel cleansing method comprising PEG plus ascorbic acid (standard group) for patients preparing for outpatient colonoscopy.

This phase III, multicentre, single-blind, noninferiority, randomised, controlled, trial has not yet been completed. Patients aged 40-69 years will be included as participants. Patients with a history of abdominal or pelvic surgery, constipation, inflammatory bowel disease, or severe organ dysfunction will be excluded. The target number of research participants is 540 (standard group, 270 cases; test group, 270 cases). The primary endpoint is the degree of bowel cleansing (Boston Bowel Preparation Scale [BBPS] score ≥ 6). The secondary endpoints are patient acceptability, adverse events, polyp/adenoma detection rate, number of polyps/adenomas detected, degree of bowel cleansing according to the BBPS (BBPS score ≥ 8), degree of bowel cleansing according to the Aronchik scale, and bowel cleansing time.

This trial aims to develop a "patient-first" colon cleansing regimen without the risk of inadequate bowel preparation by using both elobixibat hydrate and SP/MC.

Japan Registry of Clinical Trials (jRCT; no. s041210067; 9 September 2021; https://jrct.niph.go.jp/ ), protocol version 1.5 (May 1, 2023).

Adequate bowel preparation is an important factor in high-quality colonoscopy. It is generally accepted that a Boston Bowel Preparation Scale (BBPS) score ≥ 6 is adequate, but some reports suggest ≥ 7. Subjects who underwent colonoscopy at least twice within 3 years from August 2015 to December 2019 were included. Polyp detection rates (PDRs), adenoma detection rates (ADRs), and number of polyps including adenomas were compared stratified by baseline colonoscopy (C1) BBPS score. Among 2352 subjects, 529 had BBPS 6 (group 1) and 1823 had BBPS 7-9 (group 2) at C1. There was no significant difference in PDR or ADR at C1 and follow-up colonoscopy (C2) between the two groups. However, the numbers of polyps (1.84 vs. 1.56, P = 0.001) and adenomas (1.02 vs. 0.88, P = 0.034) at C2 were significantly higher in group 1 than group 2, respectively. Segmental BBPS score 2 in group 1 compared to group 2, especially, showed higher PDR (P = 0.001) and ADR (P = 0.007) at C2. BBPS 6 is associated with a higher number of polyps and adenomas in short-term follow-up colonoscopy than BBPS 7-9. To reduce the risk of missed polyps, a thorough examination is necessary for BBPS 6.

Background: Various predictive models have been published to identify outpatients with inadequate colonic cleansing who may benefit from intensified preparations to improve colonoscopy quality. The main objective of this study was to compare the accuracy of three predictive models for identifying poor bowel preparation in outpatients undergoing colonoscopy. Methods: This cross-sectional study included patients scheduled for outpatient colonoscopy over a 3-month period. We evaluated and compared three predictive models (Models 1-3). The quality of colonic cleansing was assessed using the Boston Bowel Preparation Scale. We calculated the area under the curve (AUC) and the corresponding 95% confidence interval for each model. Additionally, we performed simple and multiple logistic regression analyses to identify variables associated with inadequate colonic cleansing and developed a new model. Results: A total of 649 consecutive patients were included in the study, of whom 84.3% had adequate colonic cleansing quality. The AUCs of Model 1 (AUC = 0.67, 95% CI [0.63-0.70]) and Model 2 (AUC = 0.62, 95% CI [0.58-0.66]) were significantly higher than that of Model 3 (AUC = 0.54, 95% CI [0.50-0.58]; p < 0.001). Moreover, Model 1 outperformed Model 2 (p = 0.013). However, the new model did not demonstrate improved accuracy compared to the older models (AUC = 0.671). Conclusions: Among the three compared models, Model 1 showed the highest accuracy for predicting poor bowel preparation in outpatients undergoing colonoscopy and could be useful in clinical practice to decrease the percentage of inadequately prepared patients.

Colonoscopy is widely used as a colorectal cancer (CRC) screening tool. The effectiveness of a screening colonoscopy is associated with a decreased risk of CRC. However, colonoscopy is an operator-dependent procedure, and endoscopists' quality performance varies widely. This article reviewed the priority metrics and practices that contribute to high-quality screening colonoscopy in real-world clinical practice. With growing evidence, quality indicators have been subject to intense research and associated with reducing postcolonoscopy CRC incidence and mortality. Some quality metrics can reflect an endoscopy unit-based practice (i.e. quality of bowel preparation and withdrawal time). Other quality indicators primarily reflect individuals' skill and knowledge (i.e. cecal intubation rate, adenoma detection rate, and appropriately assigned follow-up colonoscopy interval). Measurement and improvement of priority quality indicators for colonoscopy should be made at both the endoscopist and unit levels. Substantial evidence supports the impact of high-quality colonoscopy in reducing the incidence of postcolonoscopy CRC.

Whether body mass index (BMI) is a risk factor for poor bowel preparation is controversial, and the optimal bowel preparation regimen for people with a high BMI is unclear.

We prospectively included 710 individuals with high BMIs (≥ 24 kg/m2) who were scheduled to undergo colonoscopy from January to November 2021 at 7 hospitals. Participants were randomly allocated into 3 L split-dose polyethylene glycol (PEG) group (n=353) and 2 L PEG group (n=357). The primary outcome was the rate of adequate bowel preparation, and the secondary outcomes included Boston Bowel Preparation Scale (BBPS) score, polyp detection rate, cecal intubation rate, and adverse reactions during bowel preparation. Furthermore, we did exploratory subgroup analyses for adequate bowel preparation.

After enrollment, 15 individuals didn't undergo colonoscopy, finally 345 participants took 3 L split-dose PEG regimen, and 350 participants took 2 L PEG regimen for colonoscopic bowel preparation. 3 L split-dose PEG regimen was superior to 2 L PEG regimen in the rate of adequate bowel preparation (81.2% vs. 74.9%, P = 0.045), BBPS score (6.71±1.15 vs. 6.37±1.31, P < 0.001), and the rate of polyp detection (62.0% vs. 52.9%, P = 0.015). The cecal intubation rate was similar in both groups (99.7%). Regarding adverse reactions, individuals were more likely to feel nausea in the 3 L PEG group (30.9% vs. 19.3%; P = 0.001); however, the degree was mild. In the subgroup analysis for adequate bowel preparation, 3 L split-dose PEG regimen performed better than 2 L PEG regimen in the overweight (BMI 25-29.9 kg/m2 ) (P = 0.006) and individuals with constipation (P = 0.044), while no significant differences were observed in relatively normal (BMI 24-24.9 kg/m2) (P = 0.593) and obese individuals (BMI ≥ 30 kg/m2) (P = 0.715).

3 L split-dose PEG regimen is superior to 2 L PEG regimen for colonoscopic Bowel Preparation in relatively high-BMI individuals, especially overweight individuals (BMI 25-29.9 kg/m2 ).

This trial was registered in the Chinese Clinical Trials Registry (ChiCTR2000039068). The date of first registration, 15/10/2020, http://www.chictr.org.cn.

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.

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.

A hyperosmolar ascorbic acid-enriched polyethylene glycol-electrolyte (ASC-PEG) lavage solution ensures excellent bowel preparation before colonoscopy; however, no study has demonstrated the efficacy of this lavage solution before surgery. This study aimed to establish the non-inferiority of ASC-PEG to the standard polyethylene glycol-electrolyte solution (PEG-ELS) in patients undergoing laparoscopic resection for colorectal cancer.

This was a prospective, single-blind, multicenter, randomized, controlled, non-inferiority clinical trial. Overall, 188 patients scheduled for laparoscopic colorectal resection for single colorectal adenocarcinomas were randomly assigned to undergo preparation with different PEG solutions between August 2017 and April 2020 at four hospitals in Japan. Participants received ASC-PEG (Group A) or PEG-ELS (Group B) preoperatively. The primary endpoint was the ratio of successful bowel preparations using the modified Aronchick scale, defined as "excellent" or "good."

After exclusion, 86 and 87 patients in Groups A and B, respectively, completed the study, and their data were analyzed. ASC-PEG was not inferior to PEG-ELS in terms of effective bowel preparation prior to laparoscopic colorectal resection (0.93 vs. 0.92; 95% confidence interval, - 0.078 to 0.099, p = 0.007). The total volume of cleansing solution intake was lower in Group A than in Group B (1757.0 vs. 1970.1 mL). Two and three severe postoperative adverse events occurred in Groups A and B, respectively. Patient tolerance of the two solutions was almost equal.

ASC-PEG is effective for preoperative bowel preparation in patients undergoing laparoscopic resection for colorectal cancer and is non-inferior to PEG-ELS.