Association between body mass index and quality of split bowel preparation

Optimizing bowel preparation quality for colonoscopy: consensus recommendations by the US Multi-Society Task Force on Colorectal Cancer

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.

Optimizing Bowel Preparation Quality for Colonoscopy: Consensus Recommendations by the US Multi-Society Task Force on Colorectal Cancer

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.

Optimizing Bowel Preparation Quality for Colonoscopy: Consensus Recommendations by the US Multi-Society Task Force on Colorectal Cancer

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.

Mortality and rate of hospitalization stratified by patients' BMI in a colonoscopy screening - a cross sectional analysis of data from Polish Colonoscopy Screening Platform

BACKGROUND

Currently, it remains unknown whether there is an association between body mass index (BMI) and complications during screening colonoscopy; hence, it remains unclear whether BMI should be considered a risk factor in pre-procedural assessments. The aim of this study was to compare mortality and unplanned hospitalization rates before and after colonoscopy stratified by patients' BMI.

MATERIAL AND METHODS

This was a retrospective cohort study of individuals who underwent screening colonoscopy as part of the Polish Colonoscopy Screening Program (PCSP). The included individuals were followed up for mortality and hospitalization episodes from 42 days prior to colonoscopy to 30 days after the procedure. Rates for the endpoints were calculated, compared, and adjusted for available data. Weighted averages of stratum-specific rates were calculated. Additional subanalyses were performed for sex and procedure type (screening colonoscopy without biopsy, colonoscopy with biopsy, or colonoscopy with polypectomy).

RESULTS

A total of 55390 individuals who underwent colonoscopy between years 2012-2015 were included. Obese individuals had significantly more hospitalizations than non-obese patients (1.94% versus 0%, p = .038). Analysis of adjusted hospitalization rates stratified by sex revealed that obese males had significantly higher related hospitalizations' rates before or after and after colonoscopy. Unadjusted and adjusted mortality rates after screening colonoscopy did not reveal significant differences between BMI categories.

CONCLUSIONS

Overweight and obesity are not clinically relevant risk factors for mortality and hospitalization six weeks before or 30 days after screening colonoscopy. Obese males may be more likely to require hospital care after colonoscopy.

Shortening Oral Simethicone-to-Colonoscopy Interval Increases Bowel Preparation Quality

BACKGROUND Simethicone can improve bowel preparation quality, but the optimal timing of oral simethicone before colonoscopy has not been determined. This study aimed to explore the effect of the time interval between oral simethicone and the start of colonoscopy (S-C) on bowel preparation quality. MATERIAL AND METHODS A total of 364 patients undergoing colonoscopy at our department from August 1, 2021 to November 30, 2021 were included in the training cohort, and 420 consecutive patients from December 15, 2021 to January 31, 2022 comprised the validation cohort. They were classified into short and long S-C groups according to the median S-C. Bowel preparation quality evaluated by the Boston Bowel Preparation Scale was compared between the 2 groups. Logistic regression analyses were performed to explore the correlation between S-C and bowel preparation quality, and we explored the effect of run-way time and time of starting colonoscopy on bowel preparation quality. RESULTS In the training cohort, 182 and 182 patients were classified into the short and long S-C groups, respectively; in the validation cohort, 210 and 210 patients were classified into the 2 groups, respectively. In the 2 cohorts, the short S-C group had a significantly higher rate of adequate/excellent bowel preparation than the long S-C group. Logistic regression analyses showed that shorter S-C, shorter run-way time, and colonoscopy in the morning were all correlated with adequate/excellent bowel preparation. CONCLUSIONS Bowel preparation quality may be affected by S-C, run-way time, and time of starting colonoscopy. S-C shortening should be given equal importance as run-way time shortening.

Multi-kingdom microbial signatures in excess body weight colorectal cancer based on global metagenomic analysis

Excess body weight (EBW) increases the risk of colorectal cancer (CRC) and is linked to lower colonoscopy compliance. Here, we extensively analyzed 981 metagenome samples from multiple cohorts to pinpoint the specific microbial signatures and their potential capability distinguishing EBW patients with CRC. The gut microbiome displayed considerable variations between EBW and lean CRC. We identify 44 and 37 distinct multi-kingdom microbial species differentiating CRC and controls in EBW and lean populations, respectively. Unique bacterial-fungal associations are also observed between EBW-CRC and lean-CRC. Our analysis revealed specific microbial functions in EBW-CRC, including D-Arginine and D-ornithine metabolism, and lipopolysaccharide biosynthesis. The best-performing classifier for EBW-CRC, comprising 12 bacterial and three fungal species, achieved an AUROC of 0.90, which was robustly validated across three independent cohorts (AUROC = 0.96, 0.94, and 0.80). Pathogenic microbial species, Anaerobutyricum hallii, Clostridioides difficile and Fusobacterium nucleatum, are EBW-CRC specific signatures. This work unearths the specific multi-kingdom microbial signatures for EBW-CRC and lean CRC, which may contribute to precision diagnosis and treatment of CRC.

Could atmospheric temperature impact on adequate colon cleansing for colonoscopy? An observational, single-institution study

PURPOSE

Several risk factors affecting the adequacy of colon cleansing have been proposed during the last decades. However, less is known about the impact that atmospheric aspects could have on adequacy of the bowel cleansing. The study aimed to investigate if the atmospheric temperature could impact on the bowel cleansing during colonoscopy.

METHODS

A prospective maintained database of the colonoscopies performed since 1^st August 2017 to 31^st March 2020 was retrospective reviewed. The primary outcome of the study was to identify if the atmospheric temperature was associated with inadequate colon cleansing during colonoscopy. Secondary outcome was to identify the other factors associated with an inadequate colon cleansing.

RESULTS

One thousand two hundred twenty patients were enrolled. High atmospheric temperature (> 25 °C) significantly influenced the colon cleansing (p < 0.0001). Adequate colon cleansing was negatively influenced by gender (female patients were associated with higher colon cleansing rate, p = 0.013), diabetes (p < 0.0001), previous pelvic surgery (p = 0.001), use of Beta-Blocker (p = 0.001), anti-platelet (p = 0.017), angiotensin converting enzyme inhibitors (p = 0.001), the adoption of 4 L Poly Ethylene Glycol solution (p = 0.009), single-dose regimen (p < 0.0001) low patients' compliance (p < 0.0001), higher age and body mass index (p < 0.0001 and p = 0.025), lower education levels (p < 0.0001). On the contrary, admission to the ward to perform bowel preparation positively impacted on colon cleansing (p = 0.002).

CONCLUSION

Atmospheric temperature could play an important role in the colon cleansing during colonoscopy, being high temperature (> 25 °C) associated with lower rate of adequate bowel cleansing. However, being this relationship never studied before, these results must be confirmed by other studies.

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.

Factors Affecting the Quality of Bowel Preparation Before Colonoscopy in Outpatient: A Prospective Observational Study

Colonoscopy is an effective method for screening colorectal cancer and adenoma, but the adenoma detection rate depends on the quality of bowel preparation. Our study investigates the influencing factors of the quality of bowel preparation before colonoscopy in outpatients and the influence of the number of walking steps on the quality of bowel preparation. We prospectively collected the clinical data of 150 outpatients undergoing colonoscopy in our department in 2019. Ordinal logistic regression shows that the overweight, not drinking, the number of walking steps before colonoscopy, and the time interval between start PEG and colonoscopy (4-6 hours) were independent factors affecting bowel preparation quality. There was a curving relationship between the reciprocal of Ottawa score and the number of walking steps before colonoscopy, and the regression equation is 1/ Ottawa score = -0.198 + 0.062 × ln steps (p = .035), a minimum of 5,270 walking steps before a colonoscopy is required for a high quality of bowel preparation.

Colonic bowel prep and body mass index: does one size fit all? A multi-centre review

PURPOSE

To investigate whether body mass index (BMI) is a risk factor for inadequate bowel preparation in elective colonoscopy. The null hypothesis being BMI does not affect bowel preparation adequacy.

METHODS

A retrospective cohort study of all participants with complete medical records who had an elective colonoscopy was conducted across three tertiary teaching hospitals in Perth, Western Australia, from January 2016 to July 2019. Participants were separated into BMI subgroups of healthy weight, overweight and obese (≥ 30 kg/m²). Data were extracted from medical records, colonoscopy and histopathology reports and were analysed using SPSS v.27.

RESULTS

Of the 1082 cases analysed, 52.7% (n = 570) were male. The median age was 61 (range 18-85 years). The median BMI was 27.8 (range 20-52). The median procedure time is 28 (range 2-69 min). Routine follow-up was the clinical indication for 65% of colonoscopy procedures undertaken during the study period. Multivariate logistic regression, controlled for statistically insignificant confounders of age, type of bowel preparation agent, grade of the endoscopist, the indication for procedure and year of procedure, showed that being obese was significantly and independently associated with inadequate bowel preparation (OR 2.0, 95% CI (1.4-2.9) p < 0.001). Another significant factor was male (OR 1.6, 95% CI (1.2-2.1) p = 0.002).

CONCLUSION

This study shows that obese patients are more likely to have inadequate bowel preparation at colonoscopy. Given the increased complication rates and health care costs associated with repeating colonoscopies and the increased risk of colorectal cancer in obese patients, it may be worth tailoring a more extensive bowel preparation regimen to ensure adequate visualisation of the colonic mucosa on the first attempt.

3 liters of polyethylene glycol vs. standard bowel preparation have equal efficacy in a Chinese population: a randomized, controlled trial

BACKGROUND

The European Society of Gastrointestinal Endoscopy recommends 4L Polyethylene Glycol (PEG) as the standard regimen for bowel preparation (BP). The current study compared 3L and 4L PEG with regard to their effectiveness, tolerability, and safety among Chinese patients to identify the best bowel cleansing method for this population.

METHODS

The study employed a prospective, observer-blinded, randomized and controlled design in a high-volume endoscopic center. Consecutive patients undergoing colonoscopy were randomly assigned (1:1) to the 3L-PEG or 4L-PEG group. The quality of bowel cleansing, procedure time, adenoma detection rate (ADR), patient tolerance, and adverse events were compared.

RESULTS

A total of 330 patients were included in the study. After exclusions, 160 cases in the 3L-PEG group and 158 cases in the 4L-PEG group were included in the final analysis. The quality of bowel cleansing (Boston Bowel Preparation Scale) for both the whole intestine and each segment had no significant differences between the groups (P > 0.05). No significant differences were found with regard to procedure time or ADR. The incidences of adverse events such as nausea (P = 0.001), vomiting (P = 0.002), and bloating (P < 0.001) were lower in the 3L-PEG group. Moreover, there was a higher rate of satisfaction in the 3L-PEG group than in the 4L-PEG group (P = 0.009).

CONCLUSIONS

3L-PEG bowel cleansing represents an optimal alternative to a 4L-PEG preparation, showing similar efficacy and superior levels of satisfaction, acceptability, and safety among users. We recommend 3L PEG as a routine regimen in the clinical setting for Chinese patients. (ClinicalTrials.gov registration number: NCT03356015, registered in 29 November, 2017, https://www.

CLINICALTRIALS

gov/ct2/show/NCT03356015).

Face-to-Face Instruction and Personalized Regimens Improve the Quality of Inpatient Bowel Preparation for Colonoscopy

BACKGROUND

Poor bowel preparation is commonly observed in inpatients undergoing colonoscopy, particularly those with higher risks for inadequate bowel preparation.

AIMS

The objective of this study was to determine whether personalized bowel preparation regimens combined with face-to-face instruction (FFI) could improve the quality of bowel preparation for inpatient.

METHODS

In this endoscopist-blinded, randomized controlled trial, 320 inpatients were enrolled and randomly allocated (1:1) to the control and intervention groups. The intervention group received FFI and personalized bowel preparation regimens, while the control group received the routine bowel preparation regimen and education. The primary outcome was adequate bowel preparation rate. Secondary outcomes included rates of procedure-related adverse events, incorrect diet restriction and laxative intake, etc. RESULTS: The adequate bowel preparation rate in the intervention group was significantly higher compared to control group [intention-to-treat (ITT) analysis: 70.0% vs 51.3%, P < 0.001; per-protocol (PP) analysis: 79.4% vs 58.6%, P < 0.001]. Bowel cleanliness was significantly improved in high-risk inpatients (ITT analysis: 65% vs 44.6%, P = 0.004; PP analysis: 73.0% vs 51.7%, P = 0.004) and in low-risk inpatients (ITT analysis: 80% vs 62.7%, P = 0.037; PP analysis: 92.3% vs 69.8%, P = 0.003). There were no significant differences between two groups regarding procedure-related adverse events.

CONCLUSIONS

Personalized bowel preparation regimens combined with FFI improve the rate of adequate bowel preparation, especially for patients with high-risk factors. As such, inpatients could benefit from this novel approach for better bowel preparation to ultimately improve the quality of colonoscopies.

Efficacy and tolerability of colonoscopies in overweight and obese patients: Results from a national database on gastrointestinal endoscopic outcomes

Background and study aims  Gastroenterologists are encountering a rising number of obese patients requiring colonoscopy. Existing literature regarding colonoscopy outcomes in this population is scant and conflicting. We analyzed a nationwide cohort of patients to identify the effects of body mass index (BMI) on colonoscopy success, efficacy, and tolerability. Patients and methods  The Clinical Outcomes Research Initiative (CORI) endoscopic database was queried for all colonoscopies in adults between 2008-2014. Patients were stratified into four cohorts based on BMI classification for comparison. Multivariable analysis was performed to identify the effect of BMI on procedure outcome, efficacy and tolerability. Results  Of 41,401 procedures, 27,696 met study inclusion criteria. Of these, 49.4 % were performed for colorectal cancer screening, most commonly under anesthesia directed sedation. Patient discomfort was the reason for an incomplete colonoscopy in 18.7 % of all cases, and more frequent among the overweight and obese cohorts. An inadequate bowel preparation was most common in the class III obesity cohort. Compared to the normal BMI group, a BMI ≥ 30 and < 40 kg/m 2 was associated with an increased odds of an incomplete colonoscopy ( P  = 0.001for overweight, P  = 0.0004 for class I/II obesity), longer procedure ( P  < 0.05 for all) and poorer tolerance ( P  < 0.0001 for class I/II obesity, P  = 0.016 for class III obesity). Anesthesia-administered sedation was more commonly used than endoscopist directed sedation amongst the obese cohort compared with the normal BMI cohort ( P  < 0.0001). Conclusions  Endoscopists should consider the increased odds of incomplete colonoscopy, longer procedures, and poorer tolerance when performing colonoscopy in obese patients to improve clinical management and procedural outcome.

Predictive factors of inadequate bowel preparation for elective colonoscopy

Aim

This study aimed to evaluate the effects of factors like demographic items, comorbidities, and drug history on the inadequacy of colonic preparation before colonoscopy.

Background

Inadequate bowel preparation can lead to lower polyp detection rates, longer procedure times, and lower cecal intubation rates.

Methods

This population-based study was conducted on 2476 Iranian adults who were referred to two tertiary centers for elective colonoscopy between 2017 and 2018. Bowel preparation quality was scored by the Boston bowel preparation scale (BBPS). Univariate and multivariate logistic regressions were used to find the independent predictors of bowel preparation inadequacy.

Results

The results showed that 31.8% of patients had inadequate bowel preparation before their colonoscopy. Higher age, BMI>25, abdominal circumference>95 cm, low fruit consumption, and history of smoking were independently correlated with bowel preparation inadequacy. Additionally, using NSAIDs and SSRIs were correlated with bowel preparation adequacy in multivariate regression analysis. Finally, age, gender, ethnicity, BMI, abdominal circumference, fruit consumption, smoking, NSAIDs, SSRIs, education, constipation, physical activity, and diabetes entered the predictive model of this study. The area under the curve (AUC) reached 0.70 in the final step.

Conclusion

The independent risk factors associated with colonic preparation inadequacy were identified, and herein, a predictive model is suggested for identifying patients with a high risk of bowel preparation inadequacy before a colonoscopy so that alternative preparation techniques can be employed among high-risk groups to yield optimal preparation quality.

Efficacy and Safety of TJP-008 Compared to 2 L PEG with Ascorbate in Colon Cleansing: A Randomized Phase 3 Trial

Background/Aims

Polyethylene glycol (PEG)-based bowel preparations are effective cleansing agents for colonoscopy. However, they require relatively large volumes to be used even with agents such as 2 L PEG with ascorbate (2LPEG). This phase 3, randomized, single-blinded, multicenter, parallel-group study compared the efficacy of 1 L PEG with high-dose ascorbate, TJP-008, to 2LPEG.

Methods

Patients undergoing colonoscopy were randomized (111) to receive TJP-008 as 1-day split dose (TJP-008-1) or 2-day split dose (TJP-008-2) regimen or to receive 2LPEG as a 2-day split dose regimen. Cleansing efficacy was evaluated using the Harefield Cleansing Scale. The primary endpoint was overall bowel cleansing success. Full analysis set (FAS) and per protocol set (PPS) analyses were performed.

Results

Of the 314 screened patients, efficacy was assessed in the following patient numbers (FAS/PPS) total (293/285), TJP-008-1 (98/94), TJP-008-2 (97/95), and 2LPEG (98/96). FAS revealed noninferiority between TJP-008 and 2LPEG with regard to overall success (TJP-008-2, 99.0%; TJP-008-1, 95.9%; 2LPEG, 94.9%; p=0.100 and p=0.733, respectively). PPS also showed noninferiority (p=0.721 and p=0.211, respectively). However, the PPS analyses showed a higher bowel cleansing score for TJP-008-2 for high-quality cleansing in the right colon (TJP-008-2 83.2% vs 2LPEG 62.5%; p=0.005).

Conclusions

TJP-008 is a new low-volume cleansing agent with a colon cleansing efficacy comparable to that of standard 2LPEG that exhibits significant safety and tolerability.

Inadequate Bowel Preparation in Pediatric Colonoscopy-Prospective Study of Potential Causes

OBJECTIVES

Inadequate bowel preparation (IBP) for colonoscopy leads to missed diagnosis, longer anesthesia time, higher chance of complications and increased costs. Adult studies have demonstrated that patient characteristics such as male gender and obesity are associated with IBP. Little is known about factors affecting bowel preparation in children. Our aim was to determine factors associated with IBP in children.

METHODS

We prospectively enrolled children undergoing outpatient colonoscopy. Quality of bowel preparation was assessed using Boston Bowel Preparation Scale (BBPS) score (range 0-9). Data collected included patient demographics, indication, and type of insurance. Patients were divided into two groups based on BBPS score-adequate (BBPS score > 5) and inadequate (BBPS score < 5) and groups were compared using Student t-test and chi-square test. Possible predictors were analyzed using multivariate logistic regression models.

RESULTS

A total of 334 children were prospectively enrolled of whom 321 were studied further (age range 2-18 years; mean age 12.4 years; 60.4% female; 85.9% Caucasian). The mean BBPS score was 6.8 (standard deviation of ±2). IBP was reported in 12.8% (41/321). Multivariable logistic regression analysis did not show statistical differences between the groups in studied patient factors including age, gender, obesity, race, insurance type, and indication for colonoscopy.

CONCLUSION

Contrary to several adult studies, the results of our prospective study did not show any relationship between examined patient factors and IBP in children. Interestingly, IBP was less prevalent in our pediatric study compared to published adult data (12.8% vs 20-40%).

A predictive score of inadequate bowel preparation based on a self-administered questionnaire: PREPA-CO

INTRODUCTION

Inadequate bowel preparation before colonoscopy has a 20-30% rate and impedes on the quality of the procedure. The aim of this study was to develop a predictive score of inadequate bowel preparation, using a patient questionnaire on potential risk factors.

METHODS

In this single center study, consecutive patients with colonoscopy indication were enrolled. The primary outcome was inadequate bowel preparation defined by Boston Bowel Preparation Scale (BBPS) score <7 or a score ≤1 in any of the 3 colonic segments.

RESULTS

A total of 561 patients were included. Inadequate bowel preparation was seen in 25.0% of cases. Seven risk factors were selected into the prediction model of inadequate bowel preparation: diabetes or obesity, irregular physical activity, cirrhosis, use of antidepressants or neuroleptics, use of opiate medication, history of surgery and history of inadequate bowel preparation. The risk score, named PREPA-CO, had an AUROC of 0.621, adequately predicted bowel cleanliness in 68.3% of cases, with a specificity of 75.8% and a negative predictive value of 80.8%.

CONCLUSION

We developed a predictive score named "Prepa-Co", allowing the identification of patients at high risk of inadequate bowel preparation. In clinical practice, this score could help tailor the prescription of the preparation to the patient.

Risk Factors of Inadequate Bowel Preparation for Screening Colonoscopy

The success of a colonoscopy in detecting and removing pre-cancerous and cancerous lesions depends heavily on the quality of bowel preparation. Despite efforts, 20–44% of colonoscopy participants have an inadequate bowel preparation. We aimed to assess and compare risk factors for inadequate bowel preparation and for the presence of advanced colorectal neoplasms in routine screening practice. In this cross-sectional study, among 8125 participants of screening colonoscopy in Germany with a comprehensive assessment of sociodemographic factors, lifestyle and medical history, we examined factors associated with inadequate bowel preparation and with findings of advanced neoplasms using adjusted log-binomial regression models. Among the identified risk factors assessed, three factors were identified that were significantly associated with inadequate bowel preparation: age ≥ 70 years (adjusted prevalence ratios, aPR, 1.50 95%CI 1.31–1.71), smoking (aPR 1.29 95%CI 1.11–1.50) and abdominal symptoms (aPR 1.14 95%CI 1.02–1.27). The same risk factors were also associated with the prevalence of advanced neoplasms in our study (aPR 1.72, 1.62 and 1.44, respectively). The risk factors associated with inadequate bowel preparation in this study were also associated with a higher risk for advanced neoplasms. Inadequate bowel preparation for colonoscopy might lead to missed colorectal cancer (CRC) precursors and the late diagnosis of CRC. People at high risk of advanced neoplasms are in particular need of enhanced bowel preparation.

Effect of Body Size on Quality of Bowel Preparation Among Patients Experiencing Colonoscopy

The body size of patients is considered to have an impact on the quality of bowel preparation. The aim of this study was to determine the effect of body mass index (BMI) on bowel preparation and prediction of unprepared patients who underwent colonoscopies. A retrospective study was undertaken with data retrieved from health records at the Center for Gastroenterology and Hepatology in Sulaymaniyah City of 12,527 colonoscopies carried out between February 2012 and December 2018. From the 12,527 records, a total of 9,659 colonoscopy examinations were included in this study. The results showed 21.3% unacceptable colon preparations: 15% poor and 6.3% inadequate. Patients with BMI of 25 and greater accounted for 36.1%. No significant association was found between increased BMI with inadequate preparation (odds ratio [OR]: 1.104, 95% confidence interval [CI]: 0.869-1.401, p value .418 and OR: 0.988, 95% CI: 0.813-1.201, p value .903). However, inadequate preparation could be associated with underweight females, who report constipation, and the elderly. Although there has been shown to be in practice an adverse bias toward patients with a high BMI, this study has shown that an increased body size does not interfere with the quality of bowel preparation or resultant colonoscopy.

An Evidence-based Approach Towards Targeted Patient Education to Improve Bowel Preparation for Colonoscopy

GOALS AND BACKGROUND

Quality of bowel preparation is an important factor influencing adenoma detection. Patient education is believed to improve the quality of bowel preparation but might be resource-intensive. We aimed to (a) identify risk factors for failed bowel preparations and (b) develop and test the efficacy of a screening tool that allows to prospectively identify and target patients at increased risk.

STUDY

Part 1: 76 consecutive outpatients with poor bowel preparation were compared with 76 age-matched and gender-matched outpatients with good preparation from the same procedure lists. Sociodemographic and clinical data were obtained from centralized databases. Univariate analysis and multivariate logistic regression was used to identify risk factors for poor bowel preparation. Part 2: on the basis of results of part 1, a screening tool for prospectively identifying patients at high risk was developed, and targeted education tested.

RESULTS

We identified the use of opioids or other constipating agents and low socioeconomic status as risk factors for poor bowel preparation [odds ratio (OR)=2.88; 95% confidence interval (CI): 1.22-6.80 and OR=2.43; 95% CI: 1.25-4.72]. Diabetes, hypothyroidism, age, and gender were found to have no effect on quality. When education was provided only to patients at increased risk, the targeted approach did not negatively affect the proportion of poor preparation (OR=6.12%; 95% CI: 4.79%-7.78% vs. OR=5.73%; 95% CI: 4.61%-7.10%).

CONCLUSIONS

Poor bowel preparation is associated with specific risk factors. Identifying and specifically targeting education at patients with these risk factors appears to facilitate more efficient use of education resources in endoscopy.

Low-residue diet for colonoscopy in veterans: Risk factors for inadequate bowel preparation and patient satisfaction and compliance

Bowel preparation with low-residue diet (LRD) has resulted in higher patient satisfaction and similar polyp detection rates compared to conventional clear liquid diet. However, there is limited experience with LRD in veterans, in whom conditions associated with poor bowel preparation are more prevalent than the general population. To examine risk factors associated with inadequate bowel preparation, we conducted a chart review of outpatient colonoscopies at the Manhattan VA Medical Center from February 2017 to April 2018. To examine patient satisfaction and compliance, we administered an anonymous questionnaire to patients undergoing outpatient colonoscopy from March to August 2018. Patients assessed by chart review (n = 660) were 92% male with a mean age of 64 years. An adequate Boston Bowel Preparation Scale score ≥2 in each colonic segment was achieved in 94% of procedures. Higher BMI, diabetes, prior inadequate bowel preparation, bowel preparation duration of two days, and opioid use were associated with inadequate bowel preparation on univariable analysis. On multiple logistic regression, only higher BMI remained a predictor, with every one-unit increase associated with a 6% increased odds of poor bowel preparation. Questionnaire responses showed 84% of patients were willing to repeat LRD bowel preparation, 85% found the process easy or acceptable, and 78% reported full adherence to LRD. These findings demonstrate that bowel preparation quality, patient satisfaction, and compliance were all high among veterans using LRD.

Efficacy, safety, and tolerability of a ready-to-drink bowel preparation in overweight and obese adults: subanalysis by body mass index from a phase III, assessor-blinded study

BACKGROUND

We performed a post hoc secondary analysis for the effect of body mass index (BMI) on the efficacy, tolerability, and safety of ready-to-drink sodium picosulfate, magnesium oxide, and citric acid (SPMC oral solution) bowel preparation.

METHODS

A phase III, randomized, assessor-blinded, multicenter, noninferiority study was conducted comparing split-dose, low-volume SPMC oral solution with a powder formulation for oral solution. A post hoc secondary analysis assessed efficacy, safety, and tolerability of SPMC oral solution stratified by BMI. BMI was classified by Centers for Disease Control and Prevention definitions (underweight and normal weight: BMI < 25 kg/m²; overweight: BMI 25-29.9 kg/m²; class I obesity: BMI 30-34.9 kg/m²; class II obesity: BMI 35-39.9 kg/m²; class III/severe obesity: BMI ⩾40 kg/m²). Prespecified primary efficacy endpoint ('responders') was the proportion of participants with 'excellent' or 'good' ratings on a modified Aronchick Scale (AS). Secondary efficacy outcomes were the quality of cleansing of the right colon as assessed by the Boston Bowel Preparation Scale (BBPS); as well as selected findings from the Mayo Clinic Bowel Prep Tolerability Questionnaire. Safety assessments included adverse events (AEs) and laboratory evaluations.

RESULTS

Between 82.8% and 92.5% of participants in any BMI group were responders by AS, and between 91.3% and 100% were responders by BBPS in the right colon. Efficacy was consistent across BMI groups, with no clear trends. Greater than 83% of participants in any BMI group found the preparation 'easy' or 'acceptable' to ingest, and the majority (>58%) rated SPMC oral solution as 'better' than a prior bowel preparation. In all BMI groups, safety data were similar to the overall cohort. Commonly reported, drug-related, treatment-emergent AEs were, by ascending BMI group, nausea (1.1%, 5.3%, 1.0%, 5.7%, and 0%) and headache (1.1%, 4.1%, 1.0%, 5.7%, and 0%).

CONCLUSIONS

Ready-to-drink SPMC oral solution had consistent, good quality colon cleansing, and favorable tolerability among participants of all BMI groups.

CLINICALTRIALSGOV REGISTRATION

NCT03017235.

Open Access Colonoscopy for Colorectal Cancer Prevention: An Evaluation of Appropriateness and Quality

BACKGROUND

Open access colonoscopy (OAC) has gained widespread acceptance and has the potential to increase colorectal cancer (CRC) screening. However, there is little data evaluating its appropriateness for CRC prevention.

AIMS

The aim of this study is to evaluate the appropriateness of OAC in CRC screening and polyp surveillance by comparing to procedures ordered by gastroenterologists (NOAC). As secondary outcomes, we compared the quality of bowel preparation and adenoma detection rate (ADR) between OAC and NOAC.

METHODS

It is retrospective single-center study. Inclusion criteria included patients > 50 years of age undergoing a colonoscopy for CRC screening and surveillance. Appropriateness was defined as those colonoscopies performed within 12 months of the recommended 2012 consensus guidelines. Secondary outcomes included the quality of bowel preparation and ADR.

RESULTS

5211 colonoscopies met inclusion criteria, and 64.9% were OAC. Screening OAC was appropriately 91.6% and NOAC 92.9% of the time (p = 0.179). Surveillance NOAC were inappropriate in 26.4% of cases, and surveillance OAC was 32.6% (p = 0.008). Multivariate analysis demonstrated that OAC did not influence ADR (OR for NOAC 0.97; 95% CI 0.86-1.1; p = 0.644) or an adequate bowel preparation (OR for NOAC 1.11; 95% CI 0.91-1.36; p = 0.306).

CONCLUSION

OAC performed similarly to NOAC for screening indications, quality of bowel preparation, and ADR. However, more surveillance procedures were inappropriate in the OAC group although both groups had a high number of inappropriate indications. Although OAC can be efficiently performed for screening indications, measures to decrease inappropriate surveillance colonoscopies are needed.

Clinical stages of colorectal cancer diagnosed in obese and overweight individuals in the Polish Colonoscopy Screening Program

Background

Obesity is a known risk factor of colorectal cancer (CRC). However, precise interconnections between excessive body fat and CRC are still vague. Therefore, the aim of this study was to assess whether stage of CRC detected in overweight and obese individuals differs from individuals with normal body mass index (BMI). A secondary aim of this study was to elucidate whether overweight and obesity influence the overall survival in CRC.

Methods

This study was a cross-sectional analysis of 163,129 individuals who underwent screening colonoscopy performed on data from a prospectively maintained database of the Polish Colonoscopy Screening Program.

Results

Overweight and obese individuals present with a less advanced CRC in screening setting (p = 0.014). This trend is the most pronounced in males (p = 0.001). Univariable and multivariable analyses revealed that obesity was a negative predictor of detection of advanced CRC with odds ratio 0.72 (95% confidence interval 0.52-1.00; p = 0.047). Furthermore, overweight and obesity were not statistically significant predictors of risk of death (p = 0.614 and p = 0.446, respectively).

Conclusions

Obese screenees present with a less advanced disease in comparison to non-obese. Moreover, survival stratified by clinical stage seems to not be influenced by BMI category. Therefore, a higher proportion of early diagnosed cancers can potentially create a survival benefit in this group.

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).

The Effect of Obesity on the Quality of Bowel Preparation for Colonoscopy: Results From a Large Observational Study

BACKGROUND

Obesity has been linked to suboptimal bowel preparation but this association has not been conclusively investigated in prospective studies.

GOALS

Our objective was to determine whether any relationship exists between obesity as measured by body mass index (BMI) and quality of bowel preparation.

STUDY

Adult patients who presented for outpatient colonoscopy at a single urban ambulatory surgery center within a 6-month period and fulfilled inclusion criteria were prospectively enrolled for the study. Patients were divided by BMI into subcategories based on the World Health Organization international classification of obesity. The Modified Aronchick scale was used to assess bowel preparation for colonoscopy. A univariate and multivariate analysis was used to determine a possible association between BMI and poor preparation.

RESULTS

A total of 1429 patients were evaluated. On the basis of inclusion criteria, 1314 subjects were analyzed, out of which 73% were overweight or obese. Inadequate bowel preparation was noted in 21.1% of patients. There was no correlation between obesity and the quality of the bowel preparation. Male gender (P=0.002), diabetes mellitus (P<0.0001), liver cirrhosis (P=0.001), coronary artery disease (P=0.003), refractory constipation (P<0.0001), and current smoking (P=0.01) were found to be independently predictive of poor bowel preparation.

CONCLUSIONS

Increased BMI is not predictive of suboptimal bowel preparation for colonoscopy. The results of our study are pivotal given the increased risk of colorectal cancer in obese patients and their known lower rate of colorectal cancer screening in certain populations. It is important to avoid subjecting these patients to an intensive bowel preparation that may further discourage screening in a patient population that requires it.

Comparing the Real-World Effectiveness of Competing Colonoscopy Preparations: Results of a Prospective Trial

OBJECTIVES

National societies provide little guidance regarding which colonoscopy bowel preps are best tolerated and most effective; this reflects a lack of comparative effectiveness studies that directly evaluate the available preps in a "real-world" setting. To address this gap, we conducted a prospective, commercially unfunded comparative effectiveness study of currently available bowel preps and measured their impact on bowel cleansing.

METHODS

We included patients aged ≥18 years, who presented for an outpatient colonoscopy at a large medical center serving more than 70 academic and community-based endoscopists who are free to prescribe the bowel prep of their choice. The primary outcome was bowel cleansing quality as measured by the Boston Bowel Preparation Scale. We performed regression models with random effects on the outcomes to adjust for confounding.

RESULTS

Approximately 4,339 colonoscopies were performed by 75 endoscopists. Magnesium citrate, MiraLAX with Gatorade, MoviPrep, OsmoPrep, Prepopik/Clenpiq, and Suprep all had significantly higher prep tolerability compared with GoLYTELY (all P < 0.05). For bowel cleansing, Suprep (7.28 ± 1.66; P < 0.001), MoviPrep (7.11 ± 1.62; P = 0.004), and MiraLAX with Gatorade (7.09 ± 1.64; P < 0.001) had higher total Boston Bowel Preparation Scale scores compared with GoLYTELY (6.67 ± 1.87); there were no significant differences among the remaining preps. Split-prep dosing was associated with better cleansing; however, men, opioid and tricyclic antidepressent users, and patients with diabetes and cirrhosis had worse cleansing (all P < 0.05).

CONCLUSIONS

In this prospective, real-world comparative effectiveness study of available bowel preps, we found that MiraLAX with Gatorade, MoviPrep, and Suprep were prospectively associated with superior tolerability and bowel cleansing.

Bowel preparation for colonoscopy: what is best and necessary for quality?

PURPOSE OF REVIEW

Colonoscopy is recognizably, the best colon cancer prevention test, provided the quality of the preparation is adequate for detection of precancerous polyps but also allowing for accurate identification of margins, thereby facilitating complete endoscopic resection. As there are many aspects effecting colon prep outcomes, it is timely to review new standards for optimizing outcomes, including product selection based on patient demographics.

RECENT FINDINGS

New national guidelines have set a minimum quality threshold for adequacy and also defined a split day delivery for oral options as the "standard of care". Several new prep options have been recently released and these data are discussed.

SUMMARY

Optimizing the quality of colon preps has major implications for clinical practice. Clinicians must recognize new targets for standard of care, providing the best approach for each individual patient, considering variable factors which may otherwise compromise success.

Which Patient-Related Factors Determine Optimal Bowel Preparation?

PURPOSE OF REVIEW

Adequate bowel cleansing before colonoscopy is a simple concept but the high rate of inadequate or incomplete bowel cleanliness and its consequences have been the subject of many studies, guidelines, and meta-analysis. The complexity resides in all the factors surrounding preparation intake such as type and regimen of bowel preparation, diets, compliance, and also patient-related factors that all influence quality of the bowel preparation. The purpose of this review is to focus specifically on patient-related factors and their challenges. Patients with lower GI bleeding are excluded from this review.

RECENT FINDINGS

Patient factors that may be associated with a poor bowel preparation were searched for in the literature. With regard to patient's characteristics, higher age, male gender, and socio-economic status (lower income, Medicaid, and lower education) were all associated with higher rates of inadequate bowel preparation. Comorbidities such as inflammatory bowel disease (IBD), in-patients, body mass index (BMI), cirrhosis, constipation, and neurological condition as well as some pharmacotherapy were also associated with inadequate bowel preparation. Studies identifying predictive patient factors as well as those studying these patients in particular showed variability in the strength of the patient factor associations. Patients taking tricyclic antidepressant, narcotics, and those with neurological conditions were identified to have a stronger association with worse bowel cleanliness. Those can be implemented with the current recommendations of split-dosing. Identifying individual factors that can impact the quality of bowel cleanliness can be challenging. Some have been well-studied in the literature such as age, in-patient status, or constipation and others such as male gender or higher BMI have required more studies to clearly conclude on any possible association. In many studies, simple recommendations like walking 30 min during the preparation, and additional instructions or support have also been added to instructions to improve motility and compliance.

Efficacy and tolerability of various bowel preparations in diabetic patients: a randomized controlled trial

Background and study aims  Diabetes mellitus (DM) is an independent risk factor for poor bowel preparation prior to colonoscopy. Bisacodyl is a stimulant laxative that may mitigate colonic dysmotility associated with diabetes. We hypothesized that adding bisacodyl to split-dose bowel preparation (SDBP) would improve the quality of bowel preparation among patients with diabetes. Patients and methods  Adult outpatients aged 18 to 80 years undergoing colonoscopy were recruited. One hundred and eighty-six patients with diabetes were randomly assigned to 1 of 3 treatment arms: 1) conventional 4 L of polyethylene glycol electrolyte lavage solution (PEG-ELS; conventional bowel preparation [CBP]); 2) split-dose of 4 L PEG-ELS (split-dose bowel preparation [SDBP]); or 3) split-dose of 4 L PEG-ELS preceded by 10 mg of oral bisacodyl 10 (SDBP-B). The primary outcome measure was bowel cleansing as indicated by Boston Bowel Preparation Scale (BBPS) score. Endoscopists were blinded to the preparation used. Secondary outcome measures were safety and patient tolerability. Results  Of the 212 patients randomized, only 186 received assigned bowel preparation. There were no differences among the three study groups with regard to age, indication, duration of DM, insulin use, narcotic use, or presence of end-organ diabetic complications. There was a trend toward better bowel preparation quality among those receiving SDBP and SDBP-B compared to those receiving CBP, but the trend was not statistically significant  ≥ 6 BBPS; 67 % vs. 83 % vs. 75 %, P  = 0.1). In terms of safety and tolerability, there were no differences among the three groups. Conclusion  Adding bisacodyl to SDBP does not improve the quality of bowel preparation in patients with DM. Further efforts are needed to optimize colonoscopy bowel preparation in this population.

Association of obesity with colonic findings in screening colonoscopy in a large population-based study

Background and aims

Obesity is associated with an increased incidence of and mortality from colorectal cancer (CRC). Screening colonoscopy seems particularly important for individuals with obesity. The aim of this study is to analyse the characteristics of screening colonoscopy in individuals with obesity.

Methods

We performed a cross-sectional analysis of records of 75,278 patients from a national colonoscopy screening programme in Poland. The database contained demographic data, colonoscopy results, self-reported data on weight and height, a standardized screenees' experience questionnaire and colorectal findings.

Results

Adenoma detection rate and advanced neoplasia detection rate increased significantly in groups of increasing body mass index (BMI). In subjects with morbid obesity, odds ratios for proximal adenoma and proximal advanced neoplasia were 1.69 (95% confidence interval (CI) 1.28-2.21) and 1.66 (95% CI 1.01-2.72), respectively, despite the fact that with BMI increasing over 30 the preparation for colonoscopy was worse. Moreover, caecal intubation increased with increasing BMI. Tolerance of colonoscopy was better and preparation for colonoscopy was less inconvenient in individuals with obesity.

Conclusions

Obesity and morbid obesity are associated with increased detection of colorectal precursor lesions and better performance of screening colonoscopy. Participation in screening colonoscopy should be emphasized among individuals with obesity, taking into account the burden of CRC in this population.

Lifestyle Factors and Bowel Preparation for Screening Colonoscopy

Purpose

The quality of bowel preparation is a major determinant of the quality of colonoscopy. This study evaluated lifestyle factors, including usual dietary style, associated with bowel preparation.

Methods

This retrospective study evaluated 1,079 consecutive subjects who underwent complete colonoscopy from December 2012 to April 2014 at National Cancer Center of Korea. Questionnaires on bowel preparation were completed by the subjects, with the quality of bowel preparation categorized as optimal (excellent or good) or suboptimal (fair, poor or inadequate). Lifestyle factors associated with bowel preparation were analyzed.

Results

The 1,079 subjects included 680 male (63.0%) and 399 female patietns (37.0%), with a mean age of 49.6 ± 8.32 years. Bowel preparation was categorized as optimal in 657 subjects (60.9%) and as suboptimal in 422 (39.1%). Univariate analyses showed no differences between groups in lifestyle factors, such as regular exercise, alcohol intake, smoking, and dietary factor. Body mass index (BMI) > 25 kg/m² was the only factor associated with suboptimal bowel preparation on both the univariate (P = 0.007) and the multivariate (odds ratio, 1.437; 95% confidence interval, 1.104–1.871; P = 0.007) analyses.

Conclusion

Most lifestyle factors, including dietary patterns, exercise, alcohol intake and smoking, were not associated with suboptimal bowel preparation in Koreans. However, BMI > 25 kg/m² was independently associated with suboptimal bowel preparation. More intense preparation regimens before colonoscopy can be helpful in subjects with BMI > 25 kg/m².

Impact of Colonoscopy Bowel Preparation Quality on Follow-up Interval Recommendations for Average-risk Patients With Normal Screening Colonoscopies: Data From the New Hampshire Colonoscopy Registry

BACKGROUND AND AIMS

National guidelines for colonoscopy screening and surveillance assume adequate bowel preparation. We used New Hampshire Colonoscopy Registry (NHCR) data to investigate the influence of bowel preparation quality on endoscopist recommendations for follow-up intervals in average-risk patients following normal screening colonoscopies.

METHODS

The analysis included 9170 normal screening colonoscopies performed on average risk individuals aged 50 and above between February 2005 and September 2013. The NHCR Procedure Form instructs endoscopists to score based on the worst prepped segment after clearing all colon segments, using the following categories: excellent (essentially 100% visualization), good (very unlikely to impair visualization), fair (possibly impairing visualization), and poor (definitely impairing visualization). We categorized examinations into 3 preparation groups: optimal (excellent/good) (n=8453), fair (n=598), and poor (n=119). Recommendations other than 10 years for examinations with optimal preparation, and >1 year for examinations with poor preparation, were considered nonadherent.

RESULTS

Of all examinations, 6.2% overall received nonadherent recommendations, including 5% of examinations with optimal preparation and 89.9% of examinations with poor preparation. Of normal examinations with fair preparation, 20.7% of recommendations were for an interval <10 years. Among those examinations with fair preparation, shorter-interval recommendations were associated with female sex, former/nonsmokers, and endoscopists with adenoma detection rate ≥20%.

CONCLUSIONS

In 8453 colonoscopies with optimal preparations, most recommendations (95%) were guideline-adherent. No guideline recommendation currently exists for fair preparation, but in this investigation into community practice, the majority of the fair preparation group received 10-year follow-up recommendations. A strikingly high proportion of examinations with poor preparation received a follow-up recommendation greater than the 1-year guideline recommendation. Provider education is needed to ensure that patients with poor bowel preparation are followed appropriately to reduce the risk of missing important lesions.

Predictors of inadequate bowel preparation for colonoscopy: a systematic review and meta-analysis

The aim of this study was to investigate factors contributing to poor bowel preparation in patients undergoing colonoscopy procedures. We used a reproducible search strategy to identify studies, searching 10 medical databases, including PubMed, Ovid, Medline, and Cochrane Library Database for reports published between 2000 and 2016. Fully published studies, evaluating risk factors for inadequate bowel preparation, were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. Pooling was conducted with both fixed-effects and random-effects models; results were presented from the random effects model when heterogeneity was significant. Odds ratios (OR) estimates with 95% confidence interval were calculated. Heterogeneity was assessed by I statistics. Twenty-four studies with a total of 49 868 patients met the inclusion criteria. Age (OR: -1.20), male sex (OR: 0.85), inpatient status (OR: 0.57), diabetes mellitus (OR: 0.58), hypertension (OR: 0.58), cirrhosis (OR: 0.49), narcotic use (OR: 0.59), constipation (OR: 0.61), stroke (OR; 0.51), and tricyclic antidepressant (TCA) use (0.51), were associated with inadequate bowel preparation. In our sensitivity analysis comparing Western and Asian countries, we found that diabetes, cirrhosis, male sex, history of stroke and TCA use were stronger risk factors for inadequate bowel preparation in Western countries than in Asian countries. We also found that history of stroke, TCA use, and race were risk factors for inadequate bowel preparation in patients receiving conventional bowel preparation compared with those receiving split-dose bowel preparation. Multiple risk factors affect the quality of bowel preparation and specific risk factors can be intervened upon, in different populations, to optimize preparation.

Efficacy and tolerability of 2-L polyethylene glycol with ascorbic acid versus sodium picosulfate with magnesium citrate: a randomized controlled trial

BACKGROUND/AIM

Previous studies comparing 2-L polyethylene glycol (PEG)-based solution with ascorbic acid (PEG/Asc) with sodium picosulfate/magnesium citrate (SP/MC) drew inconclusive results. This study aimed to compare a 2-L-PEG/Asc with SP/MC by split method in bowel cleansing efficacy, tolerability, and safety and to identify factors influencing inadequate bowel preparation.

METHOD

We performed a prospective randomized, endoscopist-blinded, single-center, controlled trial. The Aronchick scale and Ottawa bowel preparation scale (OBPS) were used to evaluate the bowel cleansing efficacy, and patients' tolerability and preferences were assessed by questionnaire.

RESULTS

In total, 223 patients were randomized to receive 2-L-PEG/Asc (n = 109) or SP/MC (n = 114). There was no significant difference in overall bowel cleansing efficacy between the two groups; however, when analyzing by individual segment, mean bowel cleansing efficacy of right colon showed a trend in favor of SP/MC group than in PEG/Asc group (OBPS; 1.55 ± 0.66 vs. 1.74 ± 0.88, P = 0.08). Furthermore, SP/MC was better tolerated than PEG/Asc based on ease of consumption and preference to receive the agents again in the future. Total adverse events were significantly lower in SP/MC group than PEG/Asc group (47.4 vs. 62.4%, P = 0.031). In multivariate analysis, later colonoscopic starting time was the only independent factor predicting inadequate bowel preparation (OR 1.39, 95% CI 1.156-1.692, P = 0.001).

CONCLUSIONS

There was no significant difference in overall bowel cleansing efficacy between PEG/Asc and SP/MC; however, SP/MC showed better tolerability and safety profile than PEG/Asc. The independent factor for inadequate bowel preparation was later colonoscopic starting time when applied split method.

Same-Day Single Dose of 2 Liter Polyethylene Glycol is Not Inferior to The Standard Bowel Preparation Regimen in Low-Risk Patients: A Randomized, Controlled Trial

OBJECTIVES

Split dose of 4 l polyethylene glycol (PEG) is currently the standard regimen for bowel preparation (BP). However, it may be unnecessary for patients without high risks (e.g., old age, constipation, and diabetes, and so on) for inadequate BP. The study aimed to compare the efficacy of bowel cleansing between low-risk patients receiving same-day, single dose of low-volume (SSL) PEG vs. standard regimen.

METHODS

This prospective, randomized, observer-blinded, non-inferiority study enrolled low-risk patients in three centers. Patients undergoing colonoscopy were randomized (1:1) to the SSL or standard group. The primary outcome was adequate BP, defined by Boston Bowel Preparation Score (BBPS) ≥6 and each segmental score ≥2. Secondary outcomes included adverse events, cecal intubation rate, and patient willingness to repeat BP, and so on.

RESULTS

Among 2,532 patients eligible for the study, 940 (37.1%) were at low risk and 792 (31.3%) at high risk for inadequate BP. The low-risk patients were randomly allocated to the SSL (n=470) or standard group (n=470). The baseline characteristics of the two groups were similar. Intention-to-treat analysis showed that adequate BP was achieved in 88.1% in the SSL group and 87.0% in the standard group (relative risk (RR) 1.10, 95% confidence interval (CI): 0.75-1.63, P=0.621). The overall BBPS was 7.3±1.2 and 7.3±1.3, respectively (P=0.948). No significant differences were found between the two groups with regards to the right, transverse, and left-segmental colon BBPS (all P>0.05). However, in terms of adverse events, patients in the SSL group reported less nausea (19.6% vs. 29.9%), vomiting (5.3% vs. 11.4%), and abdominal discomfort (2.2% vs. 6.0%) compared with those in the standard group. More patients in the SSL group were willing to repeat BP (94.0% vs. 89.5%, P=0.015).

CONCLUSIONS

For low-risk patients, the SSL regimen was not inferior to the split dose of 4 l PEG for adequacy of BP. Single dose of low-volume regimen had significantly fewer adverse events. This simplified regimen may be preferable in the "easy-to prepare" population.

Patient Characteristics Associated With Quality of Colonoscopy Preparation: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Some features of patients are associated with inadequate bowel preparation, which reduces the effectiveness of colonoscopy examination. We performed a systematic review and meta-analysis of the association between patients' sociodemographic characteristics, health conditions, and medications with inadequate bowel preparation.

METHODS

We searched the PubMed, Scopus, and Cochrane Review databases for randomized controlled trials cohort (prospective and retrospective), case-control, and cross-sectional studies published through March 2016. We collected information on study design, study population, and bowel preparation. For each factor, we obtained the odds ratio (OR) for inadequate bowel preparation. We conducted the meta-analyses using the random-effects approach and investigated any identified heterogeneity and publication bias via graphical methods, stratification, and meta-regression.

RESULTS

We performed a meta-analysis of 67 studies, comprising 75,818 patients. The estimated pooled OR for inadequate bowel preparation was small for sociodemographic characteristics: 1.14 for age, and 1.23 for male sex (excluding studies in Asia, which had substantial heterogeneity and publication bias), and 1.49 for low education. The effect of high body mass index differed significantly in studies with mostly female patients (OR, 1.05) vs those with mostly male patients (OR, 1.30) (P = .013 for the difference). ORs for constipation and cirrhosis were heterogeneous; adjusted ORs were larger than unadjusted ORs (1.97 vs 1.29 for constipation and 3.41 vs 1.36 for cirrhosis). Diabetes (OR, 1.79), hypertension (OR, 1.25), stroke or dementia (OR, 2.09), and opioid use (OR, 1.70) were associated with inadequate bowel preparation. History of abdominal surgery (OR, 0.99) did not associate with inadequate bowel preparation. Use of tricyclic antidepressants had a larger effect on risk of inadequate bowel preparation in studies of mostly female patients (OR, 2.62) than studies of mostly male patients (OR, 1.42) (P = .085 for the difference).

CONCLUSIONS

In a systematic review and meta-analysis, we found no single patient-related factor to be solely associated with inadequate bowel preparation. Health conditions and use of some medications appear to be stronger predictors than sociodemographic characteristics.

Optimal Bowel Cleansing for Colonoscopy in the Elderly Patient

Colonoscopy is an important diagnostic and screening tool for colorectal cancer detection and prevention, and adequate bowel preparation is critical for successful colonoscopy. Complications related to colonoscopy, either directly or indirectly related to the procedure, are increased in elderly patients, and the risks and benefits of colonoscopy procedures need to be carefully considered in these patients. Recent studies have shown that 4 L polyethylene glycol with a split preparation is safe and effective for elderly patients, and is the preferred preparation for patients with medical comorbidities. Preparations containing sodium phosphate are generally not recommended for the elderly because of increased renal complications. In addition, a low-residue diet may aid in tolerance and willingness to undergo the procedure compared with a clear liquid diet, with comparable bowel preparation adequacy. Risk factors for inadequate bowel preparations include poor adherence to split preparation instructions or volume of solution ingested, and certain patient-related medications and comorbidities, such as diabetes, elevated body mass index, and antidepressant or narcotic use. Methods for achieving safe and adequate bowel preparations in the elderly include clear instructions, reminder calls, and case management for potential confounding patient-related factors.

Diabetics on Narcotics Are Less Likely to Achieve Excellent Bowel Preparation Than Are Patients with Either Condition

BACKGROUND

Diabetes and chronic narcotic use negatively affect the quality of bowel preparation before colonoscopy.

AIM

To investigate whether narcotic use and diabetes have an additive negative impact on bowel preparation.

PATIENTS AND METHODS

We performed a retrospective study of 2841 patients (mean age 61 ± 10.2; 94% male) who received outpatient colonoscopies at our Veterans Affairs Medical Center between June 2012 and December 2014. We collected information related to demographics, body mass index, indications, and medical/surgical history (diabetes mellitus, stroke, cirrhosis, dementia, constipation, hypothyroidism, and use of narcotics or antidepressants/anxiolytics for more than three months). Patients were classified into four groups: (1) diabetics on narcotics, (2) diabetics only, (3) on narcotics only, and (4) neither diabetic nor using narcotics. Quality of the bowel preparation was scored using the Boston Bowel Preparation Scale (BBPS) and categorized as either excellent (BBPS ≥7, with no individual segment scoring <2) or not excellent (BBPS <7). Multivariate logistic regression analysis was performed to identify the combined impact of narcotic use and diabetes on bowel preparation.

RESULTS

Bowel preparation quality was excellent in 49%. Thirty-eight percent of patients with diabetes who were using narcotics (adjusted OR 0.6, CI [0.4, 0.8]) achieved excellent bowel preparation compared with 44% (adjusted OR 0.7, CI [0.6, 0.9]) of patients on narcotics only, 48% (adjusted OR 0.8, CI [0.7, 0.9]) of diabetics only, and 54% of patients with neither condition.

CONCLUSION

Concomitant narcotic use and diabetes have a compounding effect on the quality of bowel preparation prior to colonoscopy.

Predictors of Suboptimal Bowel Preparation Using 3-l of Polyethylene Glycol for an Outpatient Colonoscopy: A Prospective Observational Study

BACKGROUND

A 3-l polyethylene glycol (PEG) solution provided better bowel cleansing quality than a 2-l solution for outpatient colonoscopy. Predictors of suboptimal preparation using a 3-l PEG have not been previously reported.

AIMS

To investigate the possible predictors of suboptimal bowel preparation using 3-l of PEG.

METHODS

We analyzed a database of 1404 consecutive colonoscopies during a 27-month period at a community hospital. A split-dose PEG regimen was provided for morning colonoscopies, and a same-day PEG regimen was provided for afternoon colonoscopies. The level of bowel cleansing was prospectively scored according to the Boston Bowel Preparation Scale (BBPS). Possible predictors of suboptimal colon preparation, defined as a BBPS score <7, were analyzed using univariate statistics and multivariate logistic regression models.

RESULTS

The mean age of the study population (46.7 % men) was 52.5 years (range 20-80 years, SD 11.1 years), and the majority of patients (77.6 %) underwent morning colonoscopies. A suboptimal bowel preparation was reported in 17.2 % of the observed colonoscopies. In the multivariate regression analysis, constipation (odds ratio [OR] 1.60, 95 % confidence interval [CI] 1.15-2.22), male gender (OR 1.68, 95 % CI 1.25-2.25), obesity (OR 1.76, 95 % CI 1.29-2.41), and inadequate (<80 %) PEG consumption (OR 5.4, 95 % CI 2.67-10.89) were independent predictors of a suboptimal colon preparation.

CONCLUSIONS

This prospective study identified that constipation, male gender, obesity, and inadequate intake of PEG were significant risk factors for suboptimal bowel preparation using a 3-l PEG solution for outpatient colonoscopy. Interventions of optimized colonoscopy preparation should be targeted at these patient populations.

Meta-Analysis of the Effect of Bowel Preparation on Adenoma Detection: Early Adenomas Affected Stronger than Advanced Adenomas

Background and Aims

Low-quality bowel preparation reduces efficacy of colonoscopy. We aimed to summarize effects of bowel preparation on detection of adenomas, advanced adenomas and colorectal cancer.

Methods

A systematic literature search was performed regarding detection of colonic lesions after normal and low-quality bowel preparation. Reported bowel preparation quality was transformed to the Aronchick scale with its qualities “excellent”, “good”, “fair”, “poor”, and “insufficient” or “optimal” (good/excellent), “suboptimal” (fair/poor/insufficient), “adequate” (good/excellent/fair) and “inadequate” (poor/insufficient). We identified two types of studies: i) Comparative studies, directly comparing lesion detection according to bowel preparation quality, and ii) repeat colonoscopy studies, reporting results of a second colonoscopy after previous low-quality preparation.

Results

The detection of early adenomas was reduced with inadequate vs. adequate bowel preparation (Odds Ratio (OR) 0.53, CI: 0.46–0.62, p<0.001). The advanced adenomas were affected less in comparison (0.74, CI: 0.62–0.87, p<0.001). The large number of subjects considered in the present meta-analysis resulted in smaller confidence intervals compared to earlier studies. Classifying the bowel-preparation quality as suboptimal vs. optimal led to the same qualitative conclusion (OR: 0.81, CI: 0.74–0.89, p<0.001 for early adenomas, OR: 0.94, CI: 0.87–1.01, n.s. for advanced adenomas). Bowel preparation was equally important for right-sided/ flat/ serrated vs. other lesions in most observational studies but more relevant in some repeat colonoscopy studies; data regarding carcinoma detection were insufficient.

Conclusion

Inadequate bowel preparation affects detection of early colonic lesions stronger than advanced lesions.

Body mass index and quality of bowel preparation: Real life vs. clinical trials

BACKGROUND AND STUDY AIMS

Obesity is a recognised risk factor for poor bowel preparation in retrospective studies whilst corresponding data in prospective trials are marginally reported. Aims are to evaluate the relation between body mass index (BMI) and preparation quality in retrospective and interventional prospective settings and within a single centre.

PATIENTS AND METHODS

Data from a recent colorectal cancer screening registry were retrospectively analysed for the relation between BMI and adequacy of preparation. Patients were categorised as underweight (BMI<20kg/m(2)), normal (20-25kg/m(2)), overweight (25-30kg/m(2)), and obese (>30kg/m(2)). Data from a recent prospective colon preparation trial were similarly analysed.

RESULTS

541 registry patients were included. Multivariate analysis showed BMI to be an independent risk factor for inadequate preparation. Obesity was associated with odds ratio (OR) of 5.3 [95% confidence interval (CI) 1.4-19.8; p=0.01] compared to normal BMI. A significant difference was also noted in underweight but otherwise healthy individuals (OR=11.1, 95% CI 2-60; p=0.005). In the prospective study of 195 patients, obese patients had comparable rates of inadequate preparation to normal-weight individuals (OR=0.7, 95% CI 1.1-3.96; p=0.68). Underweight patients had a significantly worse preparation compared to normal BMI individuals (OR=8, 95% CI 1.1-58; p=0.04).

CONCLUSIONS

In real life, bowel preparations in obese individuals have a lower quality in comparison to normal individuals. This finding is not replicated in clinical trials. This discrepancy is likely the result of focused patient education suggesting that this is primarily a dietary compliance phenomenon. Underweight individuals appear to have worse quality of preparation independent of study design or setting.

Quality of bowel cleansing in hospitalized patients undergoing colonoscopy: A multicentre prospective regional study

BACKGROUND

Quality of bowel cleansing in hospitalized patients undergoing colonoscopy is often unsatisfactory. No study has investigated the inpatient or outpatient setting as cause of inadequate cleansing.

AIMS

To assess degree of bowel cleansing in inpatients and outpatients and to identify possible predictors of poor bowel preparation in the two populations.

METHODS

Prospective multicentre study on consecutive colonoscopies in 25 regional endoscopy units. Univariate and multivariate analysis with odds ratio estimation were performed.

RESULTS

Data from 3276 colonoscopies were analyzed (2178 outpatients, 1098 inpatients). Incomplete colonoscopy due to inadequate cleansing was recorded in 369 patients (11.2%). There was no significant difference in bowel cleansing rates between in- and outpatients in both colonic segments. In the overall population, independent predictors of inadequate cleansing both at the level of right and left colon were: male gender (odds ratio, 1.20 [1.02-1.43] and 1.27 [1.05-1.53]), diabetes mellitus (odds ratio, 2.35 [1.68-3.29] and 2.12 [1.47-3.05]), chronic constipation (odds ratio, 1.60 [1.30-1.97] and 1.55 [1.23-1.94]), incomplete purge intake (odds ratio, 2.36 [1.90-2.94] and 2.11 [1.68-2.65]) and a runway time >12h (odds ratio, 3.36 [2.40-4.72] and 2.53 [1.74-3.67]).

CONCLUSIONS

We found no difference in the rate of inadequate bowel preparation between hospitalized patients and outpatients.

Standard bowel cleansing is highly ineffective in cirrhotic patients undergoing screening colonoscopy

BACKGROUND

Few data are available on tolerability and quality of standard bowel cleansing for colonoscopy in patients with chronic disease.

AIM

We seek to evaluate the tolerability and results of lavage solution for colonoscopy in cirrhotic patients in comparison with controls.

METHODS

Fifty-three cirrhotic and fifty-two normal subjects undergoing colonoscopy were prospectively enrolled in the study. Data regarding tolerability of lavage solution were harvested at the pre-procedure visit. Data on level of bowel cleansing and other endoscopic variables were recorded after the procedure.

RESULTS

Rate of failure to complete the prescribed bowel preparation and incidence of side effects during its administration were similar between cirrhotic and normal subjects. Despite this, cirrhotic patients exhibited an insufficient level of bowel preparation with approximately half exhibiting bad colon cleansing level (49% versus 5% control, p<0.001).

CONCLUSION

Alternative bowel cleansing protocols are needed for cirrhotic subjects to better match their colonoscopic screening needs.

Predicting inadequate bowel preparation for colonoscopy in participants receiving split-dose bowel preparation: development and validation of a prediction score

BACKGROUND

Adequate bowel preparation is important for optimal colonoscopy. It is important to identify patients at risk for inadequate bowel preparation because this allows taking precautions in this specific group.

OBJECTIVE

To develop a prediction score to identify patients at risk for inadequate bowel preparation who may benefit from an intensified bowel cleansing regimen.

DESIGN

Patient and colonoscopy data were prospectively collected, whereas clinical data were retrospectively collected for a total of 1996 colonoscopies in participants who received split-dose bowel preparation. Multivariate logistic regression analyses were conducted in a random two-thirds of the cohort to develop a prediction model. Validation and evaluation of the discriminative power of the prediction model were performed within the remaining one-third of the cohort.

SETTING

Four centers, including one academic and three medium-to-large size nonacademic centers.

PATIENTS

Consecutive colonoscopies in November and December 2012. Mean age was 57.3 ± 15.9 years, 45.8% were male and indications for colonoscopy were screening and/or surveillance (27%), abdominal symptoms and/or blood loss and/or anemia (60%), inflammatory bowel disease (9%), and others (4%).

INTERVENTIONS

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Inadequate bowel preparation defined as Boston Bowel Preparation Scale score <6.

RESULTS

A total of 1331 colonoscopies were included in the development cohort, of which 172 (12.9%) had an inadequate bowel preparation. Independent factors included in the prediction model were American Society of Anesthesiologists Physical Status Classification System score ≥3, use of tricyclic antidepressants, use of opioids, diabetes, chronic constipation, history of abdominal and/or pelvic surgery, history of inadequate bowel preparation, and current hospitalization. The discriminative ability of the scale was good, with an area under the curve of 0.77 in the validation cohort.

LIMITATIONS

Study design partially retrospective, no data on patient compliance.

CONCLUSION

We developed a validated, easy-to-use prediction scale that can be used to identify subjects with an increased risk of inadequate bowel preparation with good accuracy.

Optimizing bowel preparation for colonoscopy: what are the predictors of an inadequate preparation?

BACKGROUND

This retrospective study evaluates factors that are associated with an inadequate bowel preparation.

METHODS

A chart review was performed on 2,101 patients who underwent colonoscopy. The quality of preparation was classified as adequate or inadequate. Univariate and multivariate regression analyses identified factors associated with inadequate preparations.

RESULTS

A total of 91.5% of preparations were adequate. Standard preparations using polyethylene glycol-electrolyte solution and sodium picosulfate alone were 91.1% adequate. Regimens with adjuncts were 91.9% adequate. Factors that predicted an inadequate preparation include the following: stroke/dementia (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.6 to 7.7, P = .002), opioids (OR 2.3, 95% CI 1.1 to 4.6, P = .02), male sex (OR 2.0, 95% CI 1.4 to 2.9, P = .000), calcium channel blockers (OR 1.9, 95% CI 1.1 to 3.3, P = .03), and antidepressants (OR 1.7, 95% CI 1.1 to 2.7, P = .02).

CONCLUSIONS

Several factors are associated with inadequate preparations. Adjuncts do not improve preparation quality. The effect of patient education on preparation quality is an area for further research.

3-L split-dose is superior to 2-L polyethylene glycol in bowel cleansing in Chinese population: a multicenter randomized, controlled trial

Large volume (4 L) of polyethylene glycol (PEG) solution would ensure a better quality of bowel cleansing but might be poorly tolerated. Due to the smaller body size, lower body weight, and different diet habits, the large volume of 4-L PEG might be poorly tolerated by the Chinese population. In view of this, a balance should be made between the volume and effectiveness. This study aimed to compare the effectiveness, compliance, and safety between 3-L split-dose and 2-L PEG in Chinese population. Consecutive patients scheduled for colonoscopy were recruited from 5 tertiary medical centers in South China between April and July, 2014. Patients were prospectively randomized into 2 groups: 3-L split-dose PEG (3L-group) and 2 L PEG (2L-group). The primary endpoint was bowel cleansing and was defined according to Ottawa Bowel Preparation Scale (OBPS). The safety and compliance were also evaluated. A total of 318 patients were included in the analysis. The mean total OBPS score was significantly higher in 2L-group than in 3L-group (4.4 ± 2.7 vs 2.9 ± 2.4, P < 0.001). Both the intention-to-treat and per-protocol analysis found that rates of successful and excellent bowel preparation were much higher in 3L-group (89.9% and 78.0%) than 2L-group (79.2% and 48.4%), respectively (P < 0.001). The average cecum intubation time was significantly shorter in 3L-group (8.2 ± 3.7 min) than in 2L-group (10.3 ± 4.2 min) (P = 0.04). Adenoma detection rate in right colon was slightly higher in 3L-group than in 2L-group (17.6% vs 12.6%, P = 0.21). The safety and compliance including the taste, smell, and dosage of PEG were similar between 2 groups (P > 0.05). 3-L split-dose PEG is superior to 2-L PEG by better bowel cleansing, improved safety and compliance, shorter cecum intubation time, and potentially higher adenoma detection rate in rightward colon in Chinese population.