Prospective, randomized, controlled comparison of the use of polyethylene glycol electrolyte lavage solution in four-liter versus two-liter volumes and pretreatment with either magnesium citrate or bisacodyl for colonoscopy preparation

Navigating Bowel Preparation for Colonoscopy: A Comprehensive Overview

Colorectal cancer (CRC) is the third most common cancer in the United States. Early detection through colonoscopy significantly improves survival rates. Detecting colon polyps depends on the quality of bowel preparation. However, inadequate bowel preparation remains a significant issue in clinical practice. Efforts to address this challenge have led to the development of bowel preparation regimens emphasizing efficacy, tolerability, and safety. Bowel preparation options can be categorized by their osmotic and volume properties. Isosmotic solutions based on polyethylene glycol-electrolyte lavage solutions (PEG-ELS) are available in both low-volume PEG-ELS with ascorbic acid (PEG-Asc) (e.g., MoviPrep, PLENVU) and high-volume formulations (e.g., GoLYTELY, CoLyte), as well as sulfate-free high-volume PEG-ELS formulations (SF-PEG-ELS). Hyperosmotic solutions include oral sulfate solution (OSS) (e.g., SUPREP), sodium phosphate tablets (NaP) (e.g., OsmoPrep), oral sulfate tablets (OST) (e.g., SUTAB), flavored PEG with sulfate salts (FPSS) (e.g., SUFLAVE), and magnesium citrate. Hypoosmotic solutions consist of PEG-sports drink (PEG-SD). In addition, combination solutions are available, such as sodium picosulfate with magnesium citrate (SPMC) with laxatives (e.g., CLENPIQ), and OSS with SF-PEG-ELS (Suclear). Each regimen differs in terms of cost, volume, taste, contraindications, and potential adverse effects. Therefore, clinicians must carefully evaluate each patient to determine the most suitable regimen for their patients.

High volume, low volume, or pills, which way should we go? a review of bowel preparation for colonoscopy

PURPOSE OF REVIEW

Colorectal cancer (CRC) is the second leading cause of adult cancer-related deaths in the United States. Colonoscopy is the gold standard for CRC screening. Adequate bowel preparation prior to colonoscopy is essential for good visualization, which results in higher polyp detection rates and shorter procedural times. Achieving adequate preparation prior to colonoscopy is accomplished approximately 75% of the time. This review covers current recommendations and recent updates in bowel preparation for colonoscopy.

RECENT FINDINGS

Split-dose bowel preparation is recommended, but recent studies show that same day, low-volume preparations are noninferior. Low-volume polyethylene glycol with electrolytes + ascorbic acid can achieve high-quality bowel preparation and 1-day, low-residue diets prior to colonoscopy, particularly prepackaged low-residue diets, can lead to better outcomes. Utilizing visual aids and artificial intelligence in the form of smartphone applications and quality prediction systems can also lead to higher rates of bowel preparation adequacy.

SUMMARY

An individualized approach should be used to decide on the best preparation option for patients. Lower volume, same day preparations are available and lead to better patient tolerability and compliance, along with less stringent precolonoscopy diets. Smartphone applications and artificial intelligence will allow us to better educate and guide patients with regards to following preparation instructions.

Ischemic Colitis Caused by Bowel Preparation for Colonoscopy

Background

Ischemic colitis is an adverse event which may occur during bowel preparation for colonoscopy. This study aims to clarify both the incidence and the risk factors of this complication.

Methods

This was a single-center, retrospective, observational study. All outpatients who were prescribed standardized preparation drugs for colonoscopy at the Kyoto Second Red Cross Hospital between November 2011 and March 2020 were included in the study. A split bowel preparation was carried out as follows; magnesium citrate with or without sodium picosulfate hydrate was/were used as a preparation drug on the day before the colonoscopy, and polyethylene glycol electrolyte solution or sodium phosphate was used on the morning of the endoscopic procedure. Patients were extracted from the electronic medical records and matched with the endoscopy database by examination date and hospital identification number. Following the endoscopic findings, both the incidence and risk factors for ischemic colitis arising after bowel preparation were examined.

Results

Among the 14,924 patients analyzed, ischemic colitis was observed in 14 patients (0.09%). Multivariate analysis revealed that old age (≥ 75 years old) and strong preparation (magnesium citrate with sodium picosulfate and polyethylene glycol electrolyte solution) for constipated patients were independent risk factors for ischemic colitis (odds ratio: 3.64 (95% confidence interval (CI): 1.36 - 9.77) and 4.27 (95% CI: 1.45 - 12.53), respectively).

Conclusions

The age 75 years and above and strong preparation for patients with constipation were independent risk factors for ischemic colitis prior to colonoscopy. Careful attention should be paid to bowel preparation before colonoscopy for patients aged ≥ 75 years and for those with constipation.

Combination of bisacodyl suppository and 1 L polyethylene glycol plus ascorbic acid is a non-inferior and comfortable regimen compared to 2 L polyethylene glycol plus ascorbic acid

BACKGROUND AND AIM

Appropriate bowel cleansing before colonoscopy is an important factor in increasing the detection rate of lesions. Low-volume polyethylene glycol (PEG) plus ascorbic acid (PEG-Asc) reduces the dosage of bowel preparation agent, but still presents discomfort to patients. The primary aim of the present study was to compare the efficacy of bowel cleansing between 2 L PEG-Asc (control) and 1 L PEG-Asc with bisacodyl suppository (suppository) groups, and the secondary aim was to investigate complications and tolerability between the two groups.

METHODS

This was a single-center prospective randomized controlled study. We identified 168 patients scheduled for colonoscopy between August 2017 and January 2018 and randomly assigned them to the control or to the suppository groups. Efficacy of bowel cleansing was assessed using the Boston Bowel Preparation Scale (BBPS), and side-effects were surveyed using questionnaires.

RESULTS

No significant difference was detected in baseline characteristics including insertion and withdrawal times, and adenoma detection rates between the two groups. Total BBPS score was 7.93 ± 1.06 and 7.74 ± 1.02 in the control and suppository groups, respectively (P = 0.22). Incidence of abdominal pain and nausea was not statistically different, whereas that of sleep disturbance and anal discomfort was higher in the control group. (P = 0.00).

CONCLUSIONS

One liter PEG-Asc with bisacodyl suppository resulted in an equivalent bowel-cleansing outcome with reduced patient discomfort compared to 2 L PEG-Asc. Therefore, PEG-Asc with bisacodyl suppository represents a potential alternative and increases patient compliance with bowel preparation.

Efficacy and Tolerability of Prucalopride in Bowel Preparation for Colonoscopy: A Systematic Review and Meta-Analysis

INTRODUCTION

Adequate bowel preparation is a vital determinant for the success of colonoscopy. However, individuals who undergo bowel preparation for colonoscopy can experience major discomfort. To solve this problem, adding prucalopride to the prepared solution may reduce intake volume, decreasing discomfort and side effects. We performed meta-analyses and systematic review of available randomized controlled trials.

METHODS

Meta-analyses were conducted to evaluate the overall relative risk and 95% confidence intervals in the combined studies for the assessment of primary outcome, which is the efficacy of bowel preparation with the addition of prucalopride.

RESULTS

Four randomized controlled trials involving 581 patients were included. When data were pooled for all patients in two non-inferiority studies, no significant difference in the quality of bowel preparation was observed between patients receiving prucalopride plus bowel preparation solution at a lower volume and those receiving the existing solution (relative risk: 0.94; 95% confidence interval: 0.86-1.03). The effects of prucalopride on acceptability, adverse events, adenoma detection rate, and polyp detection rate did not significantly differ from those of traditional solutions.

CONCLUSIONS

The combination of prucalopride and bowel preparation solution at a lower volume has similar effects on bowel preparation, and its use did not increase the occurrence of adverse effects.

Comparison of the effect of 1-day and 2-day low residue diets on the quality of bowel preparation before colonoscopy

BACKGROUND/AIM

Low residue diet (LRD) has a similar quality of bowel preparation with clear liquid diet before colonoscopy, but improved patient tolerance. However, the optimal LRD duration is still controversial. In this study, we have compared the effect of a 1-day LRD and 2-day LRD on the quality of bowel preparation and patient tolerance.

PATIENTS AND METHODS

Our prospective, randomized, single-blind trial, single-blind, trial compared two dietary regimens administered the day before colonoscopy. All patients were administered PEG-ES and simethicone for bowel preparation. The primary outcome measure was bowel preparation quality. The secondary outcome measures were insertion time, withdrawal time, polyp detection rate, patient tolerance, and willingness to use the same diet for bowel preparation again. Bowel preparation quality was evaluated using the Boston bowel preparation scale (BBPS). Patient tolerance was evaluated using a hunger-comfort scale.

RESULTS

There was no significant difference in bowel preparation quality between the 2 groups. The 1-day LRD group had a BBPS score of 6.48 ± 1.59 points, while the 2-day LRD group had a score of 6.42 ± 1.06 points (P > 0.05). The groups reported similar colonoscope insertion times, withdrawal times, polyp detection rates and patient tolerance scores (hunger-comfort scores). The numbers of patients who reported that compliance as easy or very easy were 126 (78.2%) in the 1-day group versus 88 (55.0%) in the 2 day group (P < 0.05) and the numbers who were willing to use the diet again in the future were 154 (95.7%) in the 1-day group versus 131 (81.9%) in the 2 day group (P < 0.05).

CONCLUSION

LRD duration (1 day or 2 days) had no significant effect on bowel preparation quality. Patients in the 1-day LRD group had higher tolerance and satisfaction levels than patients in the 2-day LRD group. However, overall satisfaction was higher with the 1-day LRD group than with the 2-day LRD group.

Quality measures improving endoscopic screening of colorectal cancer: a review of the literature

Colorectal cancer (CRC) is a major health-care problem all over the world and CRC screening is effective in reducing mortality and increasing the 5-year survival. Colonoscopy has a central role in CRC screening. It can be performed as a primary test, as a recall policy after a positive result of another screening test, and for surveillance. Since effectiveness of endoscopic screening depends on adequate detection and removal of colonic polyps, consistent quality measures, which are useful in enhancing the diagnostic yield of examination, are essential. Areas covered: The aim of this review is to analyze current evidence from literature supporting quality measures able to refine endoscopic screening of colorectal cancer. Expert commentary: Quality measures namely a) time slot allotted to colonoscopy, b) assessment of indication, c) bowel preparation, d) Cecal intubation, e) withdrawal time, f) adenoma detection rate, g) proper management of lesions (polypectomy technique, polyps retrieval rate and tattooing of resection sites), and h) adequate follow-up intervals play a key role in identifying malignant and at-risk lesions and improving the outcome of screening. Adherence to these quality measures is critical to maximize the effectiveness of CRC screening, as well as, a proper technique of colonoscopy and a quality report of the procedure. Among all recommended measures, adenoma detection rate is the most important and must be kept above the recommended quality threshold by all physicians practicing in the setting of screening.

A randomized controlled trial comparing the efficacy of 1-L polyethylene glycol solution with ascorbic acid plus prucalopride versus 2-L polyethylene glycol solution with ascorbic acid for bowel preparation

OBJECTIVES

Bowel cleansing is a major patient complaint during colonoscopy. Adding laxatives to the bowel preparation is effective in replacing a portion of bowel preparation solution and reducing its volume. Prucalopride is a serotonin receptor agonist that stimulates gastrointestinal motility and provides propulsive force for defecation. This study aimed to compare 1 L polyethylene glycol (PEG) with ascorbic acid (Asc) plus 2 mg prucalopride (1LP/AP) and 2 L PEG with Asc (2LP/A) for colonoscopy preparation with respect to bowel-cleansing quality and side effects.

METHODS

A single-center, randomized, prospective study was conducted with 260 outpatients administered either 1LP/AP or 2LP/A. The primary endpoint was bowel preparation quality, which was evaluated using the Boston Bowel Preparation Scale and Aronchick Bowel Preparation Scale, and the secondary endpoints were patient tolerability and acceptability, assessed by a questionnaire-based survey.

RESULTS

The adequate bowel preparation rates were 88.5% and 83.1% in the 2LP/A and 1LP/AP groups, respectively, and the efficacy of 1LP/AP was equivalent to the control regimen (p=.216). Other colonoscopic variables including adenoma detection rate were similar in both groups. Patient tolerability and acceptability were not significantly different, but patients in the 1LP/AP group were more willing to repeat the same regimen (p=.039).

CONCLUSIONS

Bowel preparation quality with 1LP/AP was equivalent to that with 2LP/A, which did not increase the occurrence of side effects, but it reduced the volume of the solution ingested, and increased patient satisfaction.

Colonic transit time and pressure based on Bernoulli's principle

PURPOSE

Variations in the caliber of human large intestinal tract causes changes in pressure and the velocity of its contents, depending on flow volume, gravity, and density, which are all variables of Bernoulli's principle. Therefore, it was hypothesized that constipation and diarrhea can occur due to changes in the colonic transit time (CTT), according to Bernoulli's principle. In addition, it was hypothesized that high amplitude peristaltic contractions (HAPC), which are considered to be involved in defecation in healthy subjects, occur because of cecum pressure based on Bernoulli's principle.

METHODS

A virtual healthy model (VHM), a virtual constipation model and a virtual diarrhea model were set up. For each model, the CTT was decided according to the length of each part of the colon, and then calculating the velocity due to the cecum inflow volume. In the VHM, the pressure change was calculated, then its consistency with HAPC was verified.

RESULTS

The CTT changed according to the difference between the cecum inflow volume and the caliber of the intestinal tract, and was inversely proportional to the cecum inflow volume. Compared with VHM, the CTT was prolonged in the virtual constipation model, and shortened in the virtual diarrhea model. The calculated pressure of the VHM and the gradient of the interlocked graph were similar to that of HAPC.

CONCLUSION

The CTT and HAPC can be explained by Bernoulli's principle, and constipation and diarrhea may be fundamentally influenced by flow dynamics.

Optimal intake of clear liquids during preparation for afternoon colonoscopy with low-volume polyethylene glycol plus ascorbic acid

BACKGROUND AND STUDY AIMS

The standard colonoscopy preparation regimen in Japan for afternoon procedures is sequential intake of 1 L of polyethylene glycol electrolyte lavage solution containing ascorbic acid (PEG-ASC), 0.5 L of clear liquid, 0.5 L of PEG-ASC, and finally 0.25 L of clear fluids (all at a rate of 0.25 L every 15 min). However, this regimen seems poorly tolerated and complicated for many patients compared to previous regimen of polyethylene glycol electrolyte lavage solution. The aim of this study was to evaluate an alternate regimen of 0.5 L of PEG-ASC followed by 0.25 L clear liquids, repeated 3 times.

PATIENTS AND METHODS

This was a single-blinded, non-inferiority, randomized controlled study. Subjects were randomized to the standard regimen or the alternate regimen using a web-based registry system. All patients were instructed to eat a pre-packaged, low residue diet and to take sodium picosulfate hydrate the day before colonoscopy. The Boston Bowel Preparation Scale was used to evaluate bowel cleansing, and a 3-point scale was used to assess mucosal visibility. The primary endpoint was successful bowel cleansing. The acceptability, tolerability, safety, and endoscopic findings of these two regimens were secondary endpoints.

RESULTS

 A total of 409 patients were randomized to either the standard regimen (n = 204, males 54.0 %, mean age 65.5 years) or the alternate regimen (n = 205, 54.6 %, 65.0 years). The rates of successful bowel cleansing were 71.1 % (64.3 - 77.2 %) with the standard regimen vs. 75.1 % (68.6 - 80.9 %) with the alternate regimen (95 % lower confidence limit, for the difference = - 4.6, non-inferiority P  < 0.05). No significant differences were found in tolerability, safety, and endoscopic findings.

CONCLUSION

 The alternate regimen and standard regimen are clinically equivalent with respect to cleansing efficacy and acceptability, tolerability, safety, and endoscopic findings. These results are good news for patients with difficulty drinking the first liter of PEG-ASC.

Randomized controlled trial: Standard versus supplemental bowel preparation in patients with Bristol stool form 1 and 2

BACKGROUND

Bristol stool form 1 and 2 is an important predictor of inadequate bowel preparation.

AIM

To evaluate the efficacy of supplemental preparation in bowel cleansing quality among patients with Bristol stool form 1 and 2, as well as the feasibility of tailored bowel preparation guided by Bristol stool form scale.

METHODS

Patients with Bristol stool form 1 and 2 from 3 Chinese tertiary hospitals randomly received either 2 L PEG-ELP (group A) or 10 mg bisacodyl plus 2 L PEG-ELP (group B); patients with Bristol stool form 3 to 7 received 2 L PEG-ELP (group C) for bowel preparation. The primary endpoint is the rate of adequate bowel reparation for the whole colon. The adequate bowel preparation rate for separate colon segments, the polyp detection rate (PDR), tolerability, acceptability, sleeping quality and compliance were evaluated as secondary endpoints.

RESULTS

700 patients were randomized. In per-protocol analysis, patients in group B attained significantly higher successful preparation rate than group A (88.7% vs. 61.2%, p<0.001) and similar with group C (88.7% vs. 85.0%, p = 0.316). The PDR in group B was significantly higher than group A (43.2% vs. 25.7%, p<0.001). Acceptability was much higher in group B and C.

CONCLUSIONS

10 mg bisacodyl plus 2 L PEG-ELP can significantly improve both bowel preparation quality and PDR in patients with Bristol stool form 1 and 2. Bristol stool form scale may be an easy and efficient guide for tailored bowel preparation before colonoscopy.

Comparable Efficacy of a 1-L PEG and Ascorbic Acid Solution Administered with Bisacodyl versus a 2-L PEG and Ascorbic Acid Solution for Colonoscopy Preparation: A Prospective, Randomized and Investigator-Blinded Trial

BACKGROUND

Two liters of polyethylene glycol (PEG) solution administered with ascorbic acid (Asc) can provide efficacy similar to that of a 4-L PEG solution for colonoscopy preparation. In addition, oral bisacodyl (Bis) has been shown to reduce the volume of PEG needed for a bowel preparation with comparable efficacy. This study aimed to compare the efficacy, tolerability and safety of a 2-L PEG solution mixed with Asc versus the combination of Bis, Asc and a 1-L PEG solution.

METHODS

This was a prospective, randomized, multi-centre, single-blind, non-inferiority trial. Participants who were scheduled for colonoscopy were included and randomized to receive either 2-L PEG and Asc (2L PEG/Asc group) or 1-L PEG, Asc and 20 mg Bis (1L PEG/Asc + Bis group). The quality of bowel preparation was assessed using the Boston Bowel Preparation Scale. Data regarding tolerance, compliance and adverse events were also gathered.

RESULTS

A total of 187 participants were analyzed; 96 were allocated to the 2L PEG/Asc group and 91 to the 1L PEG/Asc + Bis group. Bowel preparation was adequate in 87.5% (84/96) of patients in the 2L PEG/Asc group and 94.5% of the 1L PEG/Asc + Bis group (86/91, p = 0.10). There was no significant difference between the two groups with respect to compliance, tolerability or safety. The patients allocated to the 1L PEG/Asc + Bis group expressed more willingness to repeat the procedure than patients in the 2L PEG/Asc group (p = 0.01).

CONCLUSIONS

Bowel preparation with Bis and a 1-L PEG/Asc solution is as effective, well-tolerated, and safe as a 2-L PEG/Asc solution.

TRIAL REGISTRATION

ClinicalTrials.gov NCT 01745835; Clinical Research Information Service (CRiS) KCT0000708.

A prospective randomized trial on the use of Coca-Cola Zero(®) vs water for polyethylene glycol bowel preparation before colonoscopy

AIM

The study aimed to determine whether Coca-Cola (Coke) Zero is a safe and effective solvent for polyethylene glycol (PEG).

METHOD

Between December 2013 and April 2014, 209 healthy adults (115 men, 95 women) scheduled for elective colonoscopy were randomized to use either Coke Zero (n = 100) or drinking water (n = 109) with PEG as bowel preparation. Each patient received two sachets of PEG to dissolve in 2 l of solvent, to be completed 6 h before colonoscopy. Serum electrolytes were measured before and after preparation. Bowel cleanliness and colonoscopy findings were recorded. Palatability of solution, adverse effects, time taken to complete and willingness to repeat the preparation were documented via questionnaire.

RESULTS

Mean palatability scores in the Coke Zero group were significantly better compared with the control group (2.31 ± 0.61 vs 2.51 ± 0.63, P = 0.019), with a higher proportion willing to use the same preparation again (55% vs 43%). The mean time taken to complete the PEG + Coke Zero solution was significantly faster (74 ± 29 min vs 86 ± 31 min, P = 0.0035). The quality of bowel cleansing was also significantly better in the Coke Zero group (P = 0.0297). There was no difference in the frequency of adverse events (P = 0.759) or the polyp detection rate (32% vs 31.2%). Consumption of either preparation did not significantly affect electrolyte levels or hydration status.

CONCLUSION

Coke Zero is a useful alternative solvent for PEG. It is well tolerated, more palatable, leads to quicker consumption of the bowel preparation and results in better quality cleansing.

Optimizing bowel preparation for colonoscopy: a guide to enhance quality of visualization

Colonoscopy is an important screening and therapeutic modality for colorectal cancer. Unlike other screening tests, colonoscopy is dependent on pre-procedure bowel preparation. If the bowel preparation is poor, significant pathology may be missed. Many factors are known to improve bowel preparation. This review will highlight those factors that may optimize the bowel preparation, including choice of bowel preparation, grading or scoring of the bowel preparation, special factors that influence preparation, and diet prior to colonoscopy that affects bowel preparation. The aim of the review is to offer suggestions and guide endoscopists on how to optimize the bowel preparation for the patients undergoing colonoscopy.

Does Polyethylene Glycol (PEG) Plus Ascorbic Acid Induce More Mucosal Injuries than Split-Dose 4-L PEG during Bowel Preparation?

BACKGROUND/AIMS

The aims of this study were to compare the bowel-cleansing efficacy, patient affinity for the preparation solution, and mucosal injury between a split dose of polyethylene glycol (SD-PEG) and low-volume PEG plus ascorbic acid (LV-PEG+Asc) in outpatient scheduled colonoscopies.

METHODS

Of the 319 patients, 160 were enrolled for SDPEG, and 159 for LV-PEG+Asc. The bowel-cleansing efficacy was rated according to the Ottawa bowel preparation scale. Patient affinity for the preparation solution was assessed using a questionnaire. All mucosal injuries observed during colonoscopy were biopsied and histopathologically reviewed.

RESULTS

There was no significant difference in bowel cleansing between the groups. The LV-PEG+Asc group reported better patient acceptance and preference. There were no significant differences in the incidence or characteristics of the mucosal injuries between the two groups.

CONCLUSIONS

Compared with SD-PEG, LV-PEG+Asc exhibited equivalent bowel-cleansing efficacy and resulted in improved patient acceptance and preference. There was no significant difference in mucosal injury between SD-PEG and LV-PEG+Asc. Thus, the LV-PEG+Asc preparation could be used more effectively and easily for routine colonoscopies without risking significant mucosal injury.

Bowel cleansing before colonoscopy: Balancing efficacy, safety, cost and patient tolerance

Effective colorectal cancer screening relies on reliable colonoscopy findings which are themselves dependent on adequate bowel cleansing. Research has consistently demonstrated that inadequate bowel preparation adversely affects the adenoma detection rate and leads gastroenterologists to recommend earlier follow up than is consistent with published guidelines. Poor preparation affects as many as 30% of colonoscopies and contributes to an increased cost of colonoscopies. Patient tolerability is strongly affected by the preparation chosen and manner in which it is administered. Poor tolerability is, in turn, associated with lower quality bowel preparations. Recently, several new developments in both agents being used for bowel preparation and in the timing of administration have brought endoscopists closer to achieving the goal of effective, reliable, safe, and tolerable regimens. Historically, large volume preparations given in a single dose were administered to patients in order to achieve adequate bowel cleansing. These were poorly tolerated, and the unpleasant taste of and significant side effects produced by these large volume regimens contributed significantly to patients’ inability to reliably complete the preparation and to a reluctance to repeat the procedure. Smaller volumes, including preparations that are administered as tablets to be consumed with water, given as split doses have significantly improved both the patient experience and efficacy, and an appreciation of the importance of the preparation to colonoscopy interval have produced additional cleansing.

A Randomized Controlled Trial Evaluating a Low-Volume PEG Solution Plus Ascorbic Acid versus Standard PEG Solution in Bowel Preparation for Colonoscopy

Evaluation of polyethylene glycol electrolyte lavage solution containing ascorbic acid (PEG-ASC) has been controversial in the point of its hyperosmolarity, especially in old population. So we therefore designed the present study to compare the efficacy, acceptability, tolerability, and safety of 1.5 L PEG+ASC and 2 L standard PEG electrolyte solution (PEG-ELS), not only in the general population, but also in patients of advanced age. Randomization was stratified by age (<70 years or 70> years), and hematological and biochemical parameters were compared in each age group, especially with respect to the safety profile of each regimen. As a result, the 1.5-L PEG-ASC regimen had higher patient acceptability than the 2-L PEG-ELS regimen. Tolerability, bowel cleansing, and safety were similar between regimens. However, we demonstrated significant statistical changes in the hematological and biochemical parameters after taking bowel preparation solutions, not only in the PEG+ASC group, but also in the PEG-ELS group. No significant differences in the safety profile were found between subjects aged less than 70 years and those aged 70 years or more; nevertheless, regardless of age, proper hydration is needed throughout the bowel preparation process.

Colon Cleansing for Colonoscopy in Patients with Ulcerative Colitis: Efficacy and Acceptability of a 2-L PEG Plus Bisacodyl Versus 4-L PEG

BACKGROUND

Low-volume preparations are gaining attention for higher acceptability but have been never evaluated in IBD. We compare the efficacy, safety, and tolerability of a 2-L PEG with a 4-L PEG solution in patients with ulcerative colitis.

METHODS

This is a multicenter, randomized, single-blind study. Adult outpatients with ulcerative colitis undergoing colonoscopy received either 2-L PEG plus bisacodyl or 4-L PEG. Bowel cleansing was assessed using the Ottawa Scale and rated as adequate if the score was ≤2 in each colon segment. Patient acceptance, satisfaction, and related symptoms were recorded.

RESULTS

Preparation was adequate in 80% of the 211 patients without any differences between groups. Mean Ottawa scores for whole and right colon were similar in the 2 groups. As concern tolerability, 83% patients in 2-L PEG arm and 44.8% in 4-L PEG arm reported no or mild discomfort (P < 0.0001) and 94.3% and 61.9% expressed their willingness to repeat the preparation (P < 0.001). Palatability was better with 2-L PEG, whereas related symptoms occurred more frequently with 4-L PEG. Regardless of preparation, split dosage was associated with better cleansing. Further predictors of poor cleansing were moderate/severe discomfort during preparation and more than 6 hours between end of preparation and colonoscopy. Extension and severity of colitis did not influence quality of preparation.

CONCLUSIONS

Low-volume PEG is not inferior to 4-L PEG for bowel cleansing in ulcerative colitis, but it is better tolerated and accepted. The time interval from solution intake and colonoscopy is the most important factor affecting quality of cleansing in ulcerative colitis.

Split-dose vs same-day reduced-volume polyethylene glycol electrolyte lavage solution for morning colonoscopy

AIM: To compare same-day whole-dose vs split-dose of 2-litre polyethylene glycol electrolyte lavage solution (PEG-ELS) plus bisacodyl for colon cleansing for morning colonoscopy.

METHODS: Consecutive adult patients undergoing morning colonoscopy were allocated into two groups i.e., same-day whole-dose or split-dose of 2-litre PEG-ELS. Investigators and endoscopists were blinded to the allocation. All patients completed a questionnaire that was designed by Aronchick and colleagues to assess the tolerability of the bowel preparation regime used. In addition, patients answered an ordinal five-value Likert scale question on comfort level during bowel preparation. Endoscopists graded the quality of bowel preparation using the Boston bowel preparation scale (BBPS). In addition, endoscopists gave an overall grading of the quality of bowel preparation. Cecal intubation time, withdrawal time, total colonoscopy time, adenoma detection rate and number of adenomas detected for each patient were recorded. Sample size was calculated using an online calculator for binary outcome non-inferiority trial. Analyses was based upon intent-to-treat. Significance was assumed at P-value < 0.05.

RESULTS: Data for 295 patients were analysed. Mean age was 62.0 ± 14.4 years old and consisted of 50.2 % male. There were 143 and 152 patients in the split-dose and whole-dose group, respectively. Split-dose was as good as whole-dose for quality of bowel preparation. The total BBPS score was as good in the split-dose group compared to the whole-dose group [6 (6-8) vs 6 (6-7), P = 0.038]. There was no difference in cecal intubation rate, cecal intubation time, withdrawal time, total colonoscopy time and adenoma detection rate. Median number of adenoma detected was marginally higher in the split-dose group [2 (1-3) vs 1 (1-2), P = 0.010]. Patients in the whole-dose group had more nausea (37.5% vs 25.2%, P = 0.023) and vomiting (16.4% vs 8.4%, P = 0.037), and were less likely to complete the bowel preparation (94.1% vs 99.3%, P = 0.020). Patients in the split-dose group were less likely to refuse the same bowel preparation regime (6.3% vs 13.8%, P = 0.033) and less likely to want to try another bowel preparation regime (53.8% vs 78.9%, P < 0.001).

CONCLUSION: Splitting reduced-volume PEG-ELS for morning colonoscopy is as effective as taking the whole dose on the same morning but is better tolerated and preferred by patients.

Miralax with gatorade for bowel preparation: a meta-analysis of randomized controlled trials

OBJECTIVES

Polyethylene glycol (PEG) is a very popular bowel preparation for colonoscopy. However, its large volume may reduce patient compliance, resulting in suboptimal preparation. Recently, a combination of Miralax and Gatorade has been studied in various randomized controlled trials (RCTs) as a lower volume and more palatable bowel preparation. However, results have varied. Therefore, we conducted a meta-analysis assessing the use of Miralax-Gatorade (M-G) vs. PEG for bowel preparation before colonoscopy.

METHODS

Multiple databases were searched (January 2014). RCTs on adults comparing M-G (238-255 g in 1.9 l that is 64 fl oz) vs. PEG (3.8-4 l) for bowel preparation before colonoscopy were included. The effects were analyzed by calculating pooled estimates of quality of bowel preparation (satisfactory, unsatisfactory, excellent), patient tolerance (nausea, cramping, bloating), and polyp detection by using odds ratio (OR) with fixed- and random-effects models.

RESULTS

Five studies met inclusion criteria (N=1,418), with mean age ranging from 53.8 to 61.3 years. M-G demonstrated statistically significantly fewer satisfactory bowel preparations as compared with PEG (OR 0.65; 95% confidence interval (CI): 0.43-0.98, P=0.04) but more willingness to repeat preparation (OR 7.32; 95% CI: 4.88-10.98, P<0.01). Furthermore, no statistically significant differences in polyp detection (P=0.65) or side effects were apparent between the two preparations for nausea (P=0.71), cramping (P=0.84), or bloating (P=0.50). Subgroup analysis revealed similar results for split-dose M-G vs. split-dose PEG.

CONCLUSIONS

M-G for bowel preparation before colonoscopy was inferior to PEG in bowel preparation quality while demonstrating no significant improvements in adverse effects or polyp detection. Therefore, PEG appears superior to M-G for bowel preparation before colonoscopy.

Optimal bowel preparation--a practical guide for clinicians

High-quality bowel preparation is essential for effective colonoscopy. Bowel preparations are judged by their safety, efficacy and tolerability. Between efficacy and tolerability, efficacy is the clinical priority because inadequate preparations are disruptive and costly. Achieving high rates of adequate preparation depends first on using split-dose or same-day dosing. Patients who have medical predictors of inadequate preparation quality (for example chronic constipation) should be prescribed more aggressive preparations and patients who have factors that predict they are less likely to follow the instructions (such as English not being their first language) should receive intensified education. On the day of the procedure, patients with persistent brown effluent should be considered for large-volume enemas or additional oral preparation before proceeding with colonoscopy. During the procedure, preparation quality should be graded after the clean-up has been completed.

A meta-analysis of randomized controlled trials of low-volume polyethylene glycol plus ascorbic acid versus standard-volume polyethylene glycol solution as bowel preparations for colonoscopy

BACKGROUND

Standard-volume polyethylene glycol (PEG) gut lavage solutions are safe and effective, but they require the consumption of large volumes of fluid. A new lower-volume solution of PEG plus ascorbic acid has been used recently as a preparation for colonoscopy.

AIM

A meta-analysis was performed to compare the performance of low-volume PEG plus ascorbic acid with standard-volume PEG as bowel preparation for colonoscopy.

STUDY

Electronic and manual searches were performed to identify randomized controlled trials (RCTs) that compared the performance of low-volume PEG plus ascorbic acid with standard-volume PEG as bowel preparation for colonoscopy. After a methodological quality assessment and data extraction, the pooled estimates of bowel preparation efficacy during bowel cleansing, compliance with preparation, willingness to repeat the same preparation, and the side effects were calculated. We calculated pooled estimates of odds ratios (OR) by fixed- and/or random-effects models. We also assessed heterogeneity among studies and the publication bias.

RESULTS

Eleven RCTs were identified for analysis. The pooled OR for preparation efficacy during bowel cleansing and for compliance with preparation for low-volume PEG plus ascorbic acid were 1.08 (95% CI = 0.98-1.28, P = 0.34) and 2.23 (95% CI = 1.67-2.98, P<0.00001), respectively, compared with those for standard-volume PEG. The side effects of vomiting and nausea for low-volume PEG plus ascorbic acid were reduced relative to standard-volume PEG. There was no significant publication bias, according to a funnel plot.

CONCLUSIONS

Low-volume PEG plus ascorbic acid gut lavage achieved non-inferior efficacy for bowel cleansing, is more acceptable to patients, and has fewer side effects than standard-volume PEG as a bowel preparation method for colonoscopy.

Adjuncts to colonic cleansing before colonoscopy

Pre-procedural cleansing of the bowel can maximize the effectiveness and efficiency of colonoscopy. Yet, efficacy of the current gold standard colonic preparation method - high-volume oral administration of purgative agents 12-24 h prior to the procedure - is limited by several factors, such as patient compliance (due to poor palatability and inconvenience of the dosing regimen) and risks of complications (due to drug interactions or intolerance). Attempts to resolve these limitations have included providing adjunctive agents and methods to promote the colonic cleansing ability of the principal purgative agent, with the aim of lessening unpleasant side effects (such as bloating) and reducing the large ingested volume requirement. Several promising adjunctive agents are bisacodyl, magnesium citrate, senna, simethicone, metoclopramide, and prokinetics, and each are being investigated for their potential. This review provides an up to date summary of the reported investigations into the potencies and weaknesses of the key adjuncts currently being applied in clinic as supplements to the traditional bowel preparation agents. While the comparative analysis of these adjuncts showed that no single agent or method has yet achieved the goal of completely overcoming the limitations of the current gold standard preparation method, they at least provide endoscopists with an array of alternatives to help improve the suboptimal efficacy of the main cleansing solutions when used alone. To aid in this clinical endeavor, a subjective grade was assigned to each adjunct to indicate its practical value. In addition, the systematic review of the currently available agents and methods provides insight into the features of each that may be overcome or exploited to create novel drugs and strategies that may become adopted as effective bowel cleansing adjuncts or alternatives.

Same-day 2-L PEG-citrate-simethicone plus bisacodyl vs split 4-L PEG: Bowel cleansing for late-morning colonoscopy

AIM

To evaluate the efficacy, tolerability, acceptability and feasibility of bisacodyl plus low volume polyethyleneglycol-citrate-simeticone (2-L PEG-CS) taken the same day as compared with conventional split-dose 4-L PEG for late morning colonoscopy.

METHODS

Randomised, observer-blind, parallel group, comparative trial carried out in 2 centres. Out patients of both sexes, aged between 18 and 85 years, undergoing colonoscopy for diagnostic investigation, colorectal cancer screening or follow-up were eligible. The PEG-CS group received 3 bisacodyl tablets (4 tablets for patients with constipation) at bedtime and 2-L PEG-CS in the morning starting 5 h before colonoscopy. The control group received a conventional 4-L PEG formulation given as split regimen; the morning dose was taken with the same schedule of the low volume preparation. The Ottawa Bowel Preparation Scale (OBPS) score was used as the main outcome measure.

RESULTS

A total of 164 subjects were enrolled and 154 completed the study; 78 in the PEG-CS group and 76 in the split 4-L PEG group. The two groups were comparable at baseline. The OBPS score in the PEG-CS group (3.09 ± 2.40) and in the PEG group (2.39 ± 2.55) were equivalent (difference +0.70; 95%CI: -0.09-1.48). This was confirmed by the rate of successful bowel cleansing in the PEG-CS group (89.7%) and in the PEG group (92.1%) (difference -2.4%; 95%CI: -11.40- 6.70). PEG-CS was superior in terms of mucosa visibility compared to PEG (85.7% vs 72.4%, P = 0.042). There were no significant differences in caecum intubation rate, time to reach the caecum and withdrawal time between the two groups. The adenoma detection rate was similar (PEG-CS 43.6% vs PEG 44.7%). No serious adverse events occurred. No difference was found in tolerability of the bowel preparations. Compliance was equal in both groups: more than 90% of subjects drunk the whole solution. Willingness to repeat the same bowel preparations was about 90% for both regimes.

CONCLUSION

Same-day PEG-CS is feasible, effective as split-dose 4-L PEG for late morning colonoscopy and does not interfere with work and daily activities the day before colonoscopy.

Efficacy and acceptability of sodium picosulphate/magnesium citrate vs low-volume polyethylene glycol plus ascorbic acid for colon cleansing: a randomized controlled trial

AIM

The study compared the efficacy, safety and tolerability of a low-volume picosulphate/magnesium citrate preparation with that of polyethylene glycol plus ascorbic acid (PEG + ASC) in a randomized clinical trial (RCT).

METHOD

A multicentre randomized, single-blinded study was designed. Adult outpatients undergoing colonoscopy received either picosulphate/magnesium citrate (Group 1) or PEG + ASC (Group 2). Bowel cleansing was assessed using the Boston Bowel Preparation Scale (BBPS) and rated as adequate if ≥ 2 in each segment. Patient acceptance, satisfaction and related symptoms were recorded.

RESULTS

Two-hundred and eighty-five patients were included. Preparation was adequate in 75.7% of patients in Group 1 and in 76.5% of patients in Group 2. The mean BBPS scores for the entire colon and for the right colon were comparable between groups. In addition, 97.1% patients in Group 1 and 84.8% in Group 2 reported no or mild discomfort (P < 0.0003) and 97.8% and 83.4% expressed their willingness to repeat the preparation (P < 0.0001). Palatability was better in Group 1, whereas related symptoms occurred more frequently in Group 2. Regardless of which preparation was used, the split regimen was associated with better cleansing compared with the same-day method (OR = 3.39; 95% CI: 1.1-10.4; P = 0.03). Other predictors of poor cleansing were comorbidity, discomfort during preparation and incomplete (< 75%) preparation.

CONCLUSION

Both picosulphate/magnesium citrate and PEG + ASC are effective for bowel preparation. Tolerability and palatability are better for picosulphate/magnesium citrate. A split schedule is associated with higher cleansing quality also for low-volume regimens.

The modern bowel preparation in colonoscopy

Adequate bowel preparation is essential for optimal colonoscopy. Suboptimal bowel preparation occurs in 25% to 40% of cases and is associated with canceled procedures, prolonged procedure time, incomplete examination, increased cost, and missed pathology. There are several effective formulations for colon cleansing with a good safety profile. Split dosing should be implemented whenever possible in an effort to enhance tolerance and adherence, and improve mucosal visibility and overall quality of the examination. In this review, modern bowel preparations are discussed including their mechanism of action, mode of use, safety, and how to optimize outcomes.

Adding pineapple juice to a polyethylene glycol-based bowel cleansing regime improved the quality of colon cleaning

BACKGROUND/AIMS

An unsuccessful colonoscopy procedure is often related to inadequate bowel cleansing. It is difficult for patients to finish the whole 4 liters of polyethylene glycol-electrolyte lavage (PEG-EL) because of its salty taste and the large quantity. Pineapple juice has been shown to be an effective agent in the dissolution of undigested food in the stomach. This study assessed the effectiveness of both 2 and 4 liters of PEG-EL in precolonoscopic bowel cleansing and the quality of colonoscopic cleaning by adding 1 liter of pineapple juice to a reduced-volume PEG-based regime.

METHODS

The patients were chosen from those undergoing a colonoscopic procedure. A total of 126 patients were randomized into 3 groups receiving 3 different PEG-EL (Golytely®) regimes, i.e. 4 liters of PEG-EL (group 1, n = 44), 2 liters of PEG-EL (group 2, n = 39) or 2 liters of PEG-EL with 1 liter of pineapple juice (Dimes® 100%; group 3, n = 43).

RESULTS

Both the 4- and 2-liter PEG-EL regimes resulted in similar bowel cleansing scores in all parts of the colonic segments. However, adding 1 liter of pineapple juice to the reduced-volume PEG-EL regime improved the quality of the cleansing on the right side of the colon and in the transverse colon. Adequate bowel cleansing was achieved in 68.1% of the patients in group 1, 63.9% in group 2 and 80% in group 3 (the lowest score in one of the segments). On the other hand, the tolerability of the regimes was similar in all 3 groups (p = 0.509).

CONCLUSIONS

Reduced PEG-EL (2 rather than 4 liters) may be sufficient for precolonoscopic bowel cleansing in the Turkish population. Administration of pineapple juice in the reduced-dose preparation regime may improve the quality of the bowel cleaning.

A clear liquid diet is not mandatory for polyethylene glycol-based bowel preparation for afternoon colonoscopy in healthy outpatients

Background/Aims

A dietary regimen consisting of a clear liquid diet (CLD) for at least 24 hours is recommended for colonoscopy preparation. However, this requirement results in problems in patient compliance with bowel preparation. The aim of this study was to evaluate the efficacy of a CLD compared with a regular diet (RD) for colonoscopy preparation using a polyethylene glycol (PEG) solution.

Methods

This was a multicenter, randomized, investigator-blind prospective study. A total of 801 healthy outpatients undergoing afternoon colonoscopy were randomized to either a CLD or RD in addition to a 4 L PEG regimen.

Results

The quality of bowel cleansing was not different between the CLD and RD groups in terms of the proportion with excellent or good preparation. In addition, no significant differences were observed between the two groups for polyp and adenoma detection rates and overall adverse events. Good compliance with bowel preparation was higher in the RD group than in the CLD group.

Conclusions

A CLD for a full day prior to colonoscopy should not be mandatory for PEG-based bowel preparation. Dietary education concerning the avoidance of high-fiber foods for 3 days before colonoscopy is sufficient, at least for healthy outpatients.

Ascorbic acid and low-volume polyethylene glycol for bowel preparation prior to colonoscopy: A meta-analysis

AIM: To evaluate the benefits of low-volume polyethylene glycol (PEG) with ascorbic acid compared to full-dose PEG for colonoscopy preparation.

METHODS: MEDLINE, Cochrane Central Register of Controlled Trials and Database of Systematic Reviews, CINAHL, PubMed, and recent abstracts from major conferences were searched (January 2012). Only randomized-controlled trials on adult subjects comparing low-volume PEG (2 L) with ascorbic acid vs full-dose PEG (3 or 4 L) were included. Meta-analysis for the efficacy of low-volume PEG with ascorbic acid and full-dose PEG were analyzed by calculating pooled estimates of number of satisfactory bowel preparations as well as adverse patient events (abdominal pain, nausea, vomiting). Separate analyses were performed for each main outcome by using OR with fixed and random effects models. Heterogeneity was assessed by calculating the I² measure of inconsistency. RevMan 5.1 was utilized for statistical analysis.

RESULTS: The initial search identified 242 articles and trials. Nine studies (n = 2911) met the inclusion criteria and were analyzed for this meta-analysis with mean age range from 53.0 to 59.6 years. All studies were randomized controlled trials on adult patients comparing large-volume PEG solutions (3 or 4 L) with low-volume PEG solutions and ascorbic acid. No statistically significant difference was noted between low-volume PEG with ascorbic acid and full-dose PEG for number of satisfactory bowel preparations (OR 1.07, 95%CI: 0.86-1.33, P = 0.56). No statistically significant difference was noted between low-volume PEG with ascorbic acid and full-dose PEG for abdominal pain (OR 1.09, 95%CI: 0.81-1.48, P = 0.56), nausea (OR 0.70, 95%CI: 0.49-1.00, P = 0.05), or vomiting (OR 0.99, 95%CI: 0.78-1.26, P = 0.95). No publication bias was noted.

CONCLUSION: Low-volume PEG with the addition of ascorbic acid demonstrates no statistically significant difference to full-dose PEG for satisfactory bowel preparation and side-effects.

Factors influencing quality of bowel preparation for colonoscopy

Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance. However, the utility of these technological advancements remain dependent on the quality of bowel preparation during colonoscopy. Poor bowel preparation has been shown to be associated with lower quality indicators of colonoscopy performance, such as reduced cecal intubation rates, increased patient discomfort and lower adenoma detection. The most popular bowel preparation regimes currently used are based on either Polyethylene glycol-electrolyte, a non-absorbable solution, or aqueous sodium phosphate, a low-volume hyperosmotic solution. Statements from various international societies and several reviews have suggested that the efficacy of bowel preparation regimes based on both purgatives are similar, although patients’ compliance with these regimes may differ somewhat. Many studies have now shown that factors other than the type of bowel preparation regime used, can influence the quality of bowel preparation among adult patients undergoing colonoscopy. These factors can be broadly categorized as either patient-related or procedure-related. Studies from both Asia and the West have identified patient-related factors such as an increased age, male gender, presence of co-morbidity and socio-economic status of patients to be associated with poor bowel preparation among adults undergoing routine out-patient colonoscopy. Additionally, procedure-related factors such as adherence to bowel preparation instructions, timing of bowel purgative administration and appointment waiting times for colonoscopy are recognized to influence the quality of colon cleansing. Knowledge of these factors should aid clinicians in modifying bowel preparation regimes accordingly, such that the quality of colonoscopy performance and delivery of service to patients can be optimised.

Bowel preparation prior to colonoscopy: a continual search for excellence

Bowel preparation prior to colonoscopy is essential to maximize the benefits of colonoscopy. Numerous bowel preparations have been studied, ranging from 4 L polyethylene glycol (PEG) to split-dose regimens to 2 L PEG with an adjunct laxative (senna, bisacodyl, ascorbic acid). Due to the large volume of PEG required for adequate bowel preparation, many studies have focused on reducing this large volume to only 2 L PEG with the addition of an adjunct. Recently, a randomized controlled trial by Tajika et al showed that the addition of mosapride to only 1.5 L PEG was non-inferior to mosapride and 2 L PEG for bowel cleansing but did provide improvements in patient tolerance. This study offers yet another potential bowel preparation for patients undergoing colonoscopy and may trigger further studies with 1.5 L PEG with an adjunct. In this letter, we discuss the current state of bowel preparation prior to colonoscopy and offer information to guide clinicians on choosing the appropriate bowel preparation for their patients.

Randomised clinical trial: low-volume bowel preparation for colonoscopy - a comparison between two different PEG-based formulations

BACKGROUND

Low-volume bowel preparations with polyethylene glycol (PEG) have been shown to provide an equivalent cleansing with improved tolerability as compared with standard PEG bowel preparation for colonoscopy. A new iso-osmotic sulphate-free formulation of PEG-Citrate-Simethicone (PEG-CS) in combination with bisacodyl has been recently developed.

AIM

To compare the quality of bowel cleansing with PEG-CS with bisacodyl vs. PEG-Ascorbate (PEG-ASC) in adult out-patients undergoing colonoscopy.

METHODS

Randomised, observer-blind, parallel group study in adult out-patients undergoing colonoscopy in five Italian centres. Both preparations were taken the evening before the procedure. Subjects were instructed to take 2-4 tablets of 5 mg bisacodyl at 16:00 hours and 2 L of PEG-CS at 20:00 hours or 2 L of PEG-ASC plus 1 L of additional water the day before colonoscopy. Bowel cleansing was evaluated according to the Boston Bowel Preparation Scale (≥6 scores were considered as 'clinical success'), and mucosal visibility according to a 3-point scale. Tolerability, acceptability and compliance were also evaluated.

RESULTS

Four hundred and eight patients were randomly allocated to PEG-CS and bisacodyl (n = 204, male patient 48%, mean age 59.1 years) or PEG-ASC (n = 204, male patient 51%, age 59.4 years). In the planned per-protocol analysis, the rate of successful preparation was 79.1% following PEG-CS with bisacodyl, and 70% following PEG-ASC (P < 0.05). Mucosal visibility was evaluated as optimal in 56.1% in the PEG-CS and bisacodyl and 46.3% in the PEG-ASC group (P < 0.05). There were no serious adverse events (AE) in each of the two experimental groups. Two subjects in the PEG-ASC group discontinued the study because of AE.

CONCLUSIONS

Polyethylene glycol-Citrate-Simethicone in combination with bisacodyl was more effective for bowel cleansing than PEG-ASC for out-patient colonoscopy. Tolerability, safety, acceptability and compliance of the two low-volume bowel preparations were similar.

Chronic methadone use, poor bowel visualization and failed colonoscopy: A preliminary study

AIM: To examine effects of chronic methadone usage on bowel visualization, preparation, and repeat colonoscopy.

METHODS: In-patient colonoscopy reports from October, 2004 to May, 2009 for methadone dependent (MD) patients were retrospectively evaluated and compared to matched opioid naive controls (C). Strict criteria were applied to exclude patients with risk factors known to cause constipation or gastric dysmotility. Colonoscopy reports of all eligible patients were analyzed for degree of bowel visualization, assessment of bowel preparation (good, fair, or poor), and whether a repeat colonoscopy was required. Bowel visualization was scored on a 4 point scale based on multiple prior studies: excellent = 1, good = 2, fair = 3, or poor = 4. Analysis of variance (ANOVA) and Pearson χ² test were used for data analyses. Subgroup analysis included correlation between methadone dose and colonoscopy outcomes. All variables significantly differing between MD and C groups were included in both univariate and multivariate logistic regression analyses. P values were two sided, and < 0.05 were considered statistically significant.

RESULTS: After applying exclusionary criteria, a total of 178 MD patients and 115 C patients underwent a colonoscopy during the designated study period. A total of 67 colonoscopy reports for MD patients and 72 for C were included for data analysis. Age and gender matched controls were randomly selected from this population to serve as controls in a numerically comparable group. The average age for MD patients was 52.2 ± 9.2 years (range: 32-72 years) years compared to 54.6 ± 15.5 years (range: 20-81 years) for C (P = 0.27). Sixty nine percent of patients in MD and 65% in C group were males (P = 0.67). When evaluating colonoscopy reports for bowel visualization, MD patients had significantly greater percentage of solid stool (i.e., poor visualization) compared to C (40.3% vs 6.9%, P < 0.001). Poor bowel preparation (35.8% vs 9.7%, P < 0.001) and need for repeat colonoscopy (32.8% vs 12.5%, P = 0.004) were significantly higher in MD group compared to C, respectively. Under univariate analysis, factors significantly associated with MD group were presence of fecal particulate [odds ratio (OR), 3.89, 95% CI: 1.33-11.36, P = 0.01] and solid stool (OR, 13.5, 95% CI: 4.21-43.31, P < 0.001). Fair (OR, 3.82, 95% CI: 1.63-8.96, P = 0.002) and poor (OR, 8.10, 95% CI: 3.05-21.56, P < 0.001) assessment of bowel preparation were more likely to be associated with MD patients. Requirement for repeat colonoscopy was also significant higher in MD group (OR, 3.42, 95% CI: 1.44-8.13, P = 0.01). In the multivariate analyses, the only variable independently associated with MD group was presence of solid stool (OR, 7.77, 95% CI: 1.66-36.47, P = 0.01). Subgroup analysis demonstrated a general trend towards poorer bowel visualization with higher methadone dosage. ANOVA analysis demonstrated that mean methadone dose associated with presence of solid stool (poor visualization) was significantly higher compared to mean dosage for clean colon (excellent visualization, P = 0.02) or for those with liquid stool only (good visualization, P = 0.01).

CONCLUSION: Methadone dependence is a risk factor for poor bowel visualization and leads to more repeat colonoscopies. More aggressive bowel preparation may be needed in MD patients.

Randomized Trial of Gatorade/Polyethylene Glycol With or Without Bisacodyl and NuLYTELY for Colonoscopy Preparation

OBJECTIVES:

We assessed the safety, efficacy, and tolerability of a new preparation of Gatorade and polyethylene glycol (PEG) for colonoscopy with or without bisacodyl compared with NuLYTELY.

METHODS:

We performed an investigator-blinded, placebo-controlled, randomized trial of 64 oz of Gatorade and 306 g of PEG (G/PEG) with or without 10 mg of bisacodyl and NuLYTELY. A total of 600 outpatients consumed their preparation the day before a morning colonoscopy. The primary endpoint was colon cleanliness assessed by the Boston Bowel Preparation Scale (BBPS). Tolerability was assessed using a subject questionnaire, and safety was assessed from a basic metabolic profile drawn before the colonoscopy.

RESULTS:

Adding bisacodyl to G/PEG caused more abdominal bloating/cramps (P<0.01) and did not result in a cleaner colon (P=0.66) compared with G/PEG without bisacodyl. The BBPS scores in both the G/PEG arms and NuLYTELY arm were not significantly different (P=0.19). Compared with subjects in the NuLYTELY arm, subjects in the G/PEG without bisacodyl arm had less nausea (P<0.04), vomiting (P<0.02), abdominal pain (P<0.02), bloating (P<0.005), difficulty drinking the liquid (P<0.0001), and found the overall preparation easier to tolerate (P<0.0001). Subjects in the combined G/PEG arms had a lower serum sodium (P<0.0007), chloride (P<0.007), and BUN (P<0.0001) levels than those in the NuLYTELY arm, but this did not cause any clinical symptoms.

CONCLUSIONS:

Bisacodyl added to G/PEG for colon lavage caused more side effects and did not result in a cleaner colon. The G/PEG preparations cleansed the colon as well as NuLYTELY, were far better tolerated, and were equally safe.

Provider acceptance, safety, and effectiveness of a computer-based decision tool for colonoscopy preparation

PURPOSE

To assess provider acceptance of recommendations by a decision tool that scans the electronic medical record and determines whether sodium phosphate may be taken. In addition, to determine decision tool effects on a composite outcome of colonoscopies canceled, rescheduled, aborted, or repeated sooner than recommended due to preparation (prep) quality; prep quality; colonoscopy duration; and patient satisfaction with and tolerance of the preparation.

METHODS

We used 4 alternating 4-week periods to compare the decision tool with usual care for outpatient colonoscopy. All decision tool decisions were reviewed in real-time by gastroenterology nurses and/or physicians. Patients completed a survey about the prep process. Endoscopists blindly rated prep quality. Colonoscopy duration and findings were recorded.

RESULTS

Of 354 persons in the decision tool group, 4 prep decisions were overridden because of patient preference or prior prep failure, but none for medical reasons. Sodium phosphate was used more frequently in the decision tool group (73% vs. 41%; P < 0.01). There was no difference between the decision tool and usual care groups in the composite outcome (26% vs. 30%, respectively; P = 0.29), acceptable prep quality (62% vs. 56%; P = 0.22), colonoscopy duration (28 vs. 30 min; P = 0.17), patient satisfaction (P = 0.38), or preparation tolerance (P = 0.37).

CONCLUSIONS

An electronic medical record-based decision tool can safely and effectively tailor the prep for colonoscopy and may improve colonoscopy efficiency and patient satisfaction.

LIMITATIONS

This study was performed at a single VA medical center and endoscopy unit, relies on the presence of relevant medical conditions and laboratory data in the electronic medical record, and had a higher than expected use of sodium phosphate during usual care.

Meta-analysis: the relative efficacy of oral bowel preparations for colonoscopy 1985-2010

BACKGROUND

Previous reviews of bowel preparation for colonoscopy have given contradictory answers.

AIM

To provide a definitive insight, using PRISMA-compliant methodology.

METHODS

A comprehensive literature review identified randomised controlled trials comparing bowel preparation regimens. Data for quality of bowel preparation were pooled in multiple meta-analyses exploring a range of inclusion criteria.

RESULTS

A total of 104 qualifying studies were identified, the majority of which involved comparisons of sodium phosphate (NaP) or polyethylene glycol (PEG). There was no significant difference demonstrated between NaP and PEG overall (OR = 0.82; 95% CI = 0.56-1.21; P = 0.36). Cumulative meta-analysis demonstrated that this conclusion has been qualitatively similar since the mid 1990s, with little quantitative change for the past 10 years. Amongst studies with previous day dosing in both study arms there was a significant advantage in favour of PEG (OR = 1.78; 95% CI = 1.13-2.81; P = 0.006). Studies focussing on results in the proximal colon also favoured PEG (OR = 2.36; 95% CI = 1.16-4.77; P = 0.012). PEG was also significantly more effective than non-NaP bowel preparation regimens (OR = 2.02; 95% CI = 1.08-3.78; P = 0.03). Other comparisons showed no significant difference between regimens.

CONCLUSIONS

Although there is no compelling evidence favouring either of the two most commonly used bowel preparation regimens, this may reflect shortcomings in study design. Where studies have ensured comparable dosage, or the clinically relevant outcome of proximal bowel clearance is considered, PEG-based regimens offer the most effective option.

[Bowel preparation before colonoscopy]

Colonoscopy is a routinely performed procedure in adults. Completion of the procedure and proper visualization of the intestinal mucosa are highly dependent on the quality of the bowel preparation. The ideal bowel preparation should be safe, well-tolerated and effective. No bowel preparation method meets the ideal criteria for bowel-cleansing prior to colonoscopy. However, polyethylene glycol-electrolyte lavage solution and sodium phosphate are the most commonly used bowel preparations before colonoscopy and colon surgery. NaP preparations appear more effective and better tolerated than standard PEG solutions but should be administered with caution in patients with preexisting or at an increased risk for electrolyte disturbances. Timing and dose are important considerations regardless of the method used. The last generation of preparations improves safety and acceptability by reducing volume of liquid ingested.

Bowel preparation with split-dose polyethylene glycol before colonoscopy: a meta-analysis of randomized controlled trials

BACKGROUND

Polyethylene glycol (PEG) is a commonly used bowel preparation for colonoscopy. Unfortunately, the standard large-volume solution may reduce patient compliance. Split-dosing of PEG has been studied in various randomized, controlled trials (RCTs). However, results have been conflicting.

OBJECTIVE

We conducted a meta-analysis to assess the role of split-dose PEG versus full-dose PEG for bowel preparation before colonoscopy.

DESIGN

Multiple databases were searched (January 2011). RCTs on adults comparing full-dose and split-dose of PEG for bowel preparation before colonoscopy were included and analyzed by calculating pooled estimates of quality of bowel preparation, preparation compliance, willingness to repeat the same preparation, and side effects by using odds ratio (OR) by fixed and random-effects models.

SETTING

Literature search.

PATIENTS

Per RCTs.

MAIN OUTCOME MEASUREMENTS

Satisfactory bowel preparation, willingness to repeat same bowel preparation, patient compliance, and side effects.

RESULTS

Five trials met inclusion criteria (N = 1232). Split-dose PEG significantly increased the number of satisfactory bowel preparations (OR 3.70; 95% CI, 2.79-4.91; P < .01) and willingness to repeat the same preparation (OR 1.76; 95% CI, 1.06-2.91; P = .03) compared with full-dose PEG. Split-dose PEG also significantly decreased the number of preparation discontinuations (OR 0.53; 95% CI, 0.28-0.98; P = .04) and nausea (OR 0.55; 95% CI, 0.38-0.79; P < .01) compared with full-dose PEG.

LIMITATIONS

Limited number of studies.

CONCLUSIONS

The use of a split-dose PEG for bowel preparation before colonoscopy significantly improved the number of satisfactory bowel preparations, increased patient compliance, and decreased nausea compared with the full-dose PEG.

Polyethylene glycol vs. sodium phosphate for bowel preparation: a treatment arm meta-analysis of randomized controlled trials

Background

Results of meta-analyses of randomized trials comparing PEG and NaP are inconsistent and have not included trials comparing either or both preps to less traditional ones.

AIM: To perform a meta-analysis by treatment arm.

Methods

Using MEDLINE and EMBASE, we identified English-language trials published from 1990 to 2008 that included PEG and/or NaP, and aggregated them by treatment arm into: 4 liter (L) PEG; 2 L PEG; split-dose PEG; two 45 ml doses of NaP +/- adjunctive medication; and NaP tablets. We compared prep quality and the proportion completing the prep.

Results

Among 71 trials (patient N = 10,201), excellent prep quality was present in 34% (CI, 26-41%) for 4 L PEG alone; 39% (CI, 26-51%) for 2 L PEG; 37% (CI, 28-46%) for split-dose PEG; 42% (CI, 33-51%) for NaP solution; 44% (CI, 38-51%) for NaP with adjunctive meds; and 58% (CI, 49-67%) for NaP tablets. Patients receiving NaP were more likely to complete the prep (97% [CI, 96-98%] vs. 90% [CI, 87-92%] for 4L PEG alone); however, completion rates for 2L PEG (98%) and split dose PEG (95%) were similar to NaP.

Conclusions

NaP tablets resulted in better prep quality and higher completion rates compared to other regimens. In comparisons limited by sample size, split dose PEG was not statistically different from NaP solution for completion rate or prep quality.

Mechanism of action and toxicities of purgatives used for colonoscopy preparation

IMPORTANCE OF THE FIELD

In developed countries, colonoscopy volume has increased dramatically over the past 15 years and is the principle method used to screen for colon cancer. Preparations used for colon cleaning have evolved over the past 30 years. Some preparations have been shown to be unsafe and are now used on a limited basis. There has been progress on limiting the volume required and on taste improvement.

AREAS COVERED IN THIS REVIEW

This review provides an account of preparations used from 1980 when PEG-based preparations became widely available, until the present day. The review highlights their mechanism of action and principle toxicities. The handling of solutes and solute-free fluid by the colon is also reviewed.

WHAT THE READER WILL GAIN

The reader will gain a perspective on the factors considered in developing colonic purgatives and the rationale for choosing selected preparations based on patient factors such as age, co-morbidities and concomitant medications.

TAKE HOME MESSAGE

Although generally safe and effective, colonic purgatives have both acute and permanent toxicities. The safest preparations utilize PEG combined with a balanced electrolyte solution. Limitations of this preparation center on the volume required and poor taste. Alternative formulations are now available; however, those using sodium phosphate have fallen out of favor due to a risk of renal toxicity.