2 L PEG plus ascorbic acid versus 4 L PEG plus simethicon for colonoscopy preparation: a randomized single-blind clinical trial. Surg Laparosc Endosc Percutan Tech. 2013;23:276-280. [PMID: 23751992 DOI: 10.1097/sle.0b013e31828e389d]

Effect of oral simethicone on the quality of colonoscopy: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

In this systematic review and meta-analysis, we aimed to investigate the effect of oral simethicone (SIM), an antifoaming agent, on the quality of colonoscopy in terms of bowel preparation quality, adenoma or polyp detection rate (ADR/PDR) and cecal intubation rate (CIR).

METHODS

All randomized controlled trials (RCTs) on the use of SIM during bowel preparation for colonoscopy published up to 17 March 2021 were identified from the PubMed, EMBASE and Cochrane Library databases. Bowel preparation quality, ADR/PDR/CIR, cecal intubation time (CIT), withdrawal time (WT), patients' tolerability, acceptability and volume of foam and bubbles were compared between the SIM and non-SIM groups.

RESULTS

Thirty-eight RCTs with 10 505 patients were included. Oral SIM significantly increased the rate of total Boston bowel preparation scale (BBPS) score ≥6 (risk ratio [RR]  1.13, P < 0.0001), acceptability (RR  1.15, P = 0.01) and the rate of no or minimal foam and bubbles (RR  1.28, P < 0.00001) and decreased abdominal distension (RR  0.64, P < 0.0001). However, it had no significant impact on overall ADR, overall PDR, CIR, CIT or WT. The rate of total BBPS score ≥6 remained significantly higher in the SIM group when a single-dose laxative regimen or a SIM dosage of ≥320 mg was employed; and ADR, PDR and CIR were significantly increased in the SIM group among colonoscopy clinicians who achieved an ADR <31%, PDR <45% and CIR <96%, respectively.

CONCLUSIONS

Oral SIM can improve bowel preparation quality, especially in patients receiving a SIM dosage of ≥320 mg or a single-dose laxative regimen. SIM may be preferred by junior colonoscopy physicians/trainees with a lower ADR/PDR or CIR.

Efficacy of elobixibat as bowel preparation agent for colonoscopy: Prospective, randomized, multi-center study

BACKGROUND AND AIM

Elobixibat is a novel ileal bile acid transporter inhibitor. This study aimed to compare the efficacy, tolerability, and safety of the combination of elobixibat and 1 L of polyethylene glycol formulation containing ascorbic acid (PEG-Asc) solution versus the combination of sodium picosulfate and 1-L PEG-Asc solution as bowel preparation for colonoscopy.

METHODS

This multi-center, randomized, observer-blinded, non-inferiority study recruited 210 outpatients who were assigned to either the elobixibat plus 1-L PEG-Asc group (group A) or the sodium picosulfate plus 1-L PEG-Asc group (group B). The quality of the bowel cleansing level was assessed by the Boston Bowel Preparation Scale (BBPS) and compared the bowel cleansing level between the groups. Data regarding bowel preparation time, patients' tolerability, and adverse events were also analyzed.

RESULTS

Data for 196 patients (99 in group A and 97 in group B) were analyzed finally. BBPS was comparable between group A and B (8.3 ± 0.9 vs. 8.3 ± 0.7; P = 0.88). Consequently, the adequate bowel preparation rate in groups A and B was 95.0% and 99.0%, respectively (-4.0%, 95% CI -9.3 to 1.5). Bowel preparation time in group A was similar to that in group B (348.2 ± 79.8 min vs. 330.8 ± 82.5 min; P = 0.13), whereas, sleep disturbance was significantly less frequent in group A than in group B (10.2% vs. 22.7%; P = 0.02).

CONCLUSIONS

The combination of elobixibat and 1-L PEG-Asc can be considered an alternative bowel preparation for colonoscopy considering the equivalent bowel cleansing effect and less frequent sleep disturbance. The Japan Registry of Clinical Trials (jRCTs41180026).

The Efficacy of Simethicone With Polyethylene Glycol for Bowel Preparation: A Systematic Review and Meta-Analysis

BACKGROUND

Simethicone (SIM) is a commonly used antifoaming agent in the clinic. However, it has not been clarified whether SIM can improve the quality of intestinal preparation and the detection rates of adenomas (ADR) and polyps (PDR). This systematic review and meta-analysis were carried out to mainly evaluate the effect of SIM in bowel preparation for colonoscopy.

MATERIALS AND METHODS

An electronic and a manual search of the literature for studies was conducted in PubMed, EMBASE, and Web of Science in all published data before February 1, 2020. The primary outcomes were the quality of bowel preparation and the ADR and PDR. All the data were calculated using a pooled estimate of risk ratio with 95% confidence intervals, and a random-effect model was used for the calculation.

RESULTS

Eighteen randomized controlled trials with 7187 patients were included in this meta-analysis. Polyethylene glycol (PEG) with SIM improved colon cleansing (P<0.00001), PDR (P=0.006) and the detection rate of lesions in the right colon (P<0.00001) when compared with PEG alone. There was no difference in the ADR (P=0.68), withdrawal time (P=0.06), cecal intubation rate (P=0.98), and cecal intubation time (P=0.65) between 2 groups. The rate of abdominal bloating rate was higher in the PEG group, but there was no significant difference in vomiting (P=0.65), and abdominal pain (P=0.25).

CONCLUSIONS

SIM improves the quality of bowel cleanliness and PDR but not ADR. Besides, SIM improves the detection rate of lesions in the right colon and decreased abdominal bloating, but do not affect vomiting and abdominal pain or cramping.

Effect of antifoaming agent on benign colorectal tumors in colonoscopy: A meta-analysis

BACKGROUND

Although several trials have shown that the addition of antifoaming agents to polyethylene glycol (PEG) can improve bowel preparation, whether PEG plus antifoaming agents have a beneficial role in the detection of benign tumors during colonoscopy has yet to be confirmed. Our aim was to clarify whether adding simethicone to PEG solution could improve the detection of benign colorectal tumors.

AIM

To clarify whether adding simethicone to PEG solution could improve the detection of benign colorectal tumors.

METHODS

The PubMed, EMBASE, and Cochrane Library databases were searched for articles published prior to September 2019. The outcomes included the detection rates of colorectal adenomas and polyps.

RESULT

Twenty studies were eligible. Although there was no difference in the colorectal adenoma detection rate (ADR), a significant effect of simethicone for diminutive adenomas (< 10 mm) was revealed in the group taking simethicone. We also found that simethicone could significantly improve the ADR in the proximal colon but did not affect the colorectal polyp detection rate. Furthermore, the subgroup analyses revealed a beneficial effect of simethicone on the ADR among Asians (P = 0.005) and those with an ADR < 25% (P = 0.003). Moreover, it was a significant finding that the low dose simethicone was as effective as the high dose one with respect to the detection of benign colorectal tumors.

CONCLUSION

In summary, the addition of simethicone to PEG might improve the detection of diminutive adenomas in the right colon by colonoscopy in Asia. Low-dose simethicone was recommended for the detection of benign colorectal tumors. However, large clinical trials are necessary to validate our results and determine the ideal dose of simethicone.

Using Etomidate and Midazolam for Screening Colonoscopies Results in More Stable Hemodynamic Responses in Patients of All Ages

Background/Aims

Recent studies have demonstrated that etomidate is a safe sedative drug with noninferior sedative effects. In our recent study, we revealed that etomidate/midazolam was more hemodynamically stable than propofol/midazolam in elderly patients undergoing colonoscopies. We aimed to investigate whether compared with propofol/midazolam, etomidate/midazolam causes fewer cardiopulmonary adverse events with noninferior efficacy for screening colonoscopies in patients of all ages.

Methods

In this single-center, randomized, double-blind study, we prospectively enrolled 200 patients. The patients were divided into etomidate and propofol groups. The primary outcome was the occurrence of cardiopulmonary adverse events. The secondary outcomes were the proportion of patients with fluctuations in vital signs (oxygen desaturation and transient hypotension), adverse events interrupting the procedure, and sedation-related outcomes.

Results

Adverse cardiopulmonary events were more common in the propofol group than the etomidate group (65.0% vs 51.0%, respectively; p=0.045). Forty-six patients (46.0%) in the propofol group and 29 (29.0%) in the etomidate group experienced fluctuations in their vital signs (p=0.013). The proportions of patients experiencing adverse events that interrupted the procedure, including myoclonus, were not significantly different between the two groups (etomidate: 20.0% vs propofol: 11.0%; p=0.079). Both groups had similar sedation-related outcomes. Multivariate analysis revealed that compared with the propofol groups, the etomidate group had a significantly lower risk of fluctuations in vital signs (odds ratio, 0.427; 95% confidence interval, 0.230 to 0.792; p=0.007).

Conclusions

Compared with using propofol/midazolam, using etomidate/midazolam for screening colonoscopies results in more stable hemodynamic responses in patients of all ages; therefore, we recommend using etomidate/midazolam for colonoscopies in patients with cardiovascular risk factors.

Simethicone decreases bloating and improves bowel preparation effectiveness: a systematic review and meta-analysis

BACKGROUND

Simethicone is an adjunct frequently used during bowel preparation before colonoscopy and currently there is no consensus on whether it should be recommended in standard bowel preparation. We performed a systematic review and meta-analysis to determine the effect simethicone has on bowel cleanliness, adenoma detection rate (ADR), and tolerability.

METHODS

We searched the literature for studies that compared colon cleansing of patients that received standard bowel preparation alone and in combination with simethicone prior to colonoscopy. The primary outcomes were colon cleanliness, ADR, and tolerability.

RESULTS

Sixteen randomized controlled trials with 5630 patients were included in meta-analysis. Overall, polyethylene glycol (PEG) with simethicone improves colon cleansing compared with PEG alone (odds ratio [OR] 1.48, CI 1.11 to 1.97, P = 0.008). This improvement was seen for single dosing (OR 1.83, CI 1.20 to 2.79, P = 0.005) but not for split dosing (OR 1.32, CI 0.72 to 2.43, P = 0.38). Overall, simethicone had no effect on ADR (OR 1.22, CI 0.81 to 1.83, P = 0.33), but in patients receiving single dosing, simethicone significantly increased ADR (OR 1.96, CI 1.22 to 3.16, P = 0.005). The rates of nausea (OR 0.96, CI 0.75 to 1.24, P = 0.75), vomiting (OR 1.00, CI 0.69 to 1.44, P = 0.99), and abdominal pain (OR 0.69, CI 0.40 to 1.18, P = 0.17) were not significantly different between PEG and PEG + simethicone cohorts. For abdominal bloating, the PEG cohort had greater odds of experiencing bloating than the PEG + simethicone cohort (OR 2.33, CI 1.70 to 3.20, P < 0.00001).

CONCLUSIONS

Simethicone improves colon cleanliness and ADR; however, this improvement is not seen in patients receiving split-dose PEG. Furthermore, simethicone decreases abdominal bloating but has no effect on nausea, vomiting, and abdominal pain. Simethicone may be a useful bowel preparation adjunct in patients unable to receive split-dose PEG.

The role of oral simethicone on the adenoma detection rate and other quality indicators of screening colonoscopy: a randomized, controlled, observer-blinded clinical trial

BACKGROUND AND AIMS

Combining simethicone (SIM) with a colon preparation agent has been shown to improve mucosal visibility during screening colonoscopy, but its effect on the adenoma detection rate (ADR) remains unclear. SIM is commonly used through the endoscope to eliminate bubbles during endoscopy. However, this practice recently has been associated with endoscope-transmitted infections. Our aims were to determine the role of SIM added to a polyethylene glycol preparation on the ADR, procedure times, colon preparation, and intraprocedural use of SIM.

METHODS

This was a randomized, controlled, observer-blinded, clinical trial of patients undergoing screening colonoscopy. Patients with a high risk of colorectal cancer were excluded. Patients were randomly assigned to 2 different preparations: polyethylene glycol plus SIM or polyethylene glycol. Two endoscopists blinded to patient preparation regimens scored its quality by using the Boston Bowel Preparation scale (BBPS) and the bubble scale. Interobserver agreement was calculated. The polyp detection rate, ADR, intraprocedural use of SIM, cecal intubation time, and withdrawal time were recorded. For study purposes, cecal intubation time and withdrawal time were combined to determine the effective procedure time.

RESULTS

No significant difference between the polyethylene glycol plus SIM and polyethylene glycol arms was seen regarding the ADR (33.3% vs 38.8%; P = .881) and effective procedure time (759.3 ± 253.1 seconds vs 800.2 ± 459.6 seconds; P = .373), respectively. Intraprocedural use of SIM as well as the bubble scale score were significantly lower in the polyethylene glycol plus SIM arm (1.6% vs 48.9%; P ≤ .05) and (0.1 vs 2.1; P ≤ .05), respectively. Conversely, no difference was found in the BBPS scores. The interobserver agreement for both scores was strong (bubble scale score kappa = .537; P < .05; BBPS score kappa = .184; P <.05).

CONCLUSION

Adding SIM to a polyethylene glycol preparation did not improve the ADR or effective procedure time. Nevertheless, it resulted in lower bubble scale scores, and more importantly, in less intraprocedural use of SIM. This simple and inexpensive intervention may have the potential to reduce the risk of endoscope-transmitted infections. (Clinical trial registration number: NCT03119168.).

Novel 1 L polyethylene glycol-based bowel preparation (NER1006): proof of concept assessment versus standard 2 L polyethylene glycol with ascorbate - a randomized, parallel group, phase 2, colonoscopist-blinded trial

Background

Colonoscopy requires colon cleansing. For this, many polyethylene glycol (PEG)-based preparations still require a high preparation-volume intake. Using an increased osmotic load with ascorbate (Asc), five new low-volume PEG-based bowel preparations (LVPEG) were tested for clinical proof of concept.

Methods

This two-part, open-label study examined preparation-volumes of 1–1.25 L and total required fluid volumes of 2–3 L. Part 1, in healthy volunteers, used mean cumulative 24-h stool weight (target > 2750 g) to identify a lead candidate. Part 2 was endoscopist-blinded: patients undergoing screening colonoscopy were randomized before treatment with the selected lead, one of two variants of it, or the control 2 L PEG + Asc. Two primary endpoints were used for proof of concept demonstration: mean 24-h stool weight and bowel cleansing success (Harefield Cleansing Scale).

Results

A total of 120 subjects (30 per group) were enrolled/randomized 1:1:1:1 (max 40:60 gender ratio) per completed Part. In Part 1, LVPEG-3 achieved the largest mean stool weight (3399 g: P < 0.0001 vs target) and was selected for Part 2. In Part 2, stool weights exceeded the target, notably for LVPEG-4 (3215 g: P < 0.001), which achieved 100% cleansing success after a total required fluid intake of 2 L. The control achieved 90% cleansing success. Adverse events were few, gastrointestinal in nature and similar between groups.

Conclusions

LVPEG-4 achieved a clinically useful combination of cleansing, safety/tolerability and low consumption volume: 1 L preparation + 1 L required additional fluid. Named NER1006, LVPEG-4 demonstrated clinical proof of concept and warrants further investigation.

Trial registration

October 2012.

Identifier: NCT01714466. EudraCT: 2012–003052-37

The trial was prospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-0988-y) contains supplementary material, which is available to authorized users.

Higher dose of simethicone decreases colonic bubbles and increases prep tolerance and quality of bowel prep: Meta-analysis of randomized controlled trials

BACKGROUND

Antifoaming agents, such as simethicone, may facilitate mucosal inspection during colonoscopy. However, conflicting results have been reported with regard to the impact of simethicone on quality of bowel preparation and adenoma detection rate (ADR).

AIM

To perform a meta-analysis of trials that have compared simethicone vs placebo during colonoscopy.

METHODS

A reproducible literature search of multiple medical databases yielded eleven studies (n = 2605) for inclusion. Studies were compared for quality of bowel preparation, bubbles quality, ADR, and tolerability. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. Pooling was conducted by both fixed-effects and random-effects models. Relative risk (RR) estimates with a 95% confidence interval (CI) were calculated. Heterogeneity was assessed by I-squared index (I²) statistics.

RESULTS

Patients’ demographic characteristics were comparable in all studies. Of the 2605 patients, 1300 were in the simethicone group, whereas 1305 were in the placebo group. Inadequate bowel preparation was much lower in the simethicone group than in the placebo group [13% vs 24.6%; RR = 0.51 (0.31-0.82); P < 0.0001]. The placebo group was more likely to have significant colonic bubbles than was the simethicone group [35% vs 8%; RR = 1.49 (1.25-1.76); P = 0.0001]. Use of simethicone resulted in a slight, statistically significant increase in ADR compared with the placebo group [26.6% vs 21.6%, RR = 1.07 (1.01-1.13); P = 0.02]. Higher doses of simethicone (> 478 mg) were more likely to result in significant reduction of inadequate bowel preparation, colonic bubbles, and to improve ADR.

CONCLUSION

Adding simethicone improved the quality of bowel preparation, visualization, tolerability, and, eventually, ADR.

Comparative efficacy of low volume versus traditional standard volume PEG on bowel preparation before colonoscopy: Protocol for an updated meta-analysis with trial sequential analysis

INTRODUCTION

Polyethylene glycol (PEG) has been considered as the first recommendation for bowel preparation prior to colonoscopy. A previous meta-analysis suggested that low volume PEG may improve the acceptability of ingesting bowel preparation solution. However, several limitations impaired the power of findings from this published meta-analysis, such as the variation in study design of included trials and adjuvant prescriptions. Moreover, some studies related to this topic have been published recently. And thus, the aim of this updated meta-analysis is to further assess the comparative efficacy of low volume versus standard volume of PEG on bowel preparation before colonoscopy with trial sequential analysis (TSA).

METHODS AND ANALYSIS

Systematic searches will be performed to capture any potential randomized controlled trials (RCTs) investigated the comparative efficacy of low volume versus traditional standard volume PEG on bowel preparation prior to colonoscopy in PubMed, EMBASE, and Cochrane Central Register of Controlled Trials. Moreover, we will also manually check the bibliographies of related studies and reviews so as to get additional studies. Two reviewers will independently screen the citation records, extract essential information, and appraise the risk of bias of each RCT in sequence. Finally, we will used the STATA software version 12.0 and TSA software version beta 0.9 to statistically analyze all data and test the robust of each pooled result, respectively.

RESULTS

We will submit the full-text of systematic review to a peer-review journal for publication.

CONCLUSION

This updated systematic review and meta-analysis with TSA will further assess the comparative efficacy and safety of low-volume versus traditional standard volume PEG for bowel preparation prior to colonoscopy. And then, a more comprehensive evidence body on low-volume compared to standard volume PEG in bowel preparation will be constructed.

Comparison of a split-dose bowel preparation with 2 liters of polyethylene glycol plus ascorbic acid and 1 liter of polyethylene glycol plus ascorbic acid and bisacodyl before colonoscopy

BACKGROUND AND AIMS

Recently, a low-volume polyethylene glycol formulation containing ascorbic acid (PEG-Asc) has proven as safe and effective as traditional 4-L PEG solutions for colonoscopy preparation. However, currently available aqueous purgative formulations are poorly tolerated. The aim of this study was to compare a split-dose 2-L PEG-Asc formulation and a 1-L PEG-Asc formulation with bisacodyl (10 mg) to determine the quality of bowel cleansing and patient tolerability.

METHODS

A single-center, randomized, observer-blinded study was performed between May 2015 and September 2015. Two hundred outpatients referred for colonoscopy were prospectively enrolled and assigned to either the split-dose 2-L PEG-Asc group or the 1-L PEG-Asc with bisacodyl 10-mg group. The Boston Bowel Preparation Scale (BBPS) and Aronchick Bowel Preparation Scale (ABPS) were used to evaluate bowel cleansing. The tolerability of the regimens and satisfaction of patients was determined based on a questionnaire.

RESULTS

Two hundred patients received either 2-L PEG-Asc or 1-L PEG-Asc with bisacodyl. Regarding colon cleansing outcome (BBPS and ABPS), the 1-L PEG-Asc with bisacodyl group showed similar but non-inferior results compared with the 2-L PEG-Asc group on both BBPS (6.92 ± 1.63 vs 6.57 ± 1.37; P = .103) and ABPS (96% vs 95%; P = 1.000) scales. Tolerability was similar for both 1-L PEG-Asc with bisacodyl and 2-L PEG-Asc.

CONCLUSIONS

1-L PEG-Asc is a suitable alternative to low-volume bowel preparation for colonoscopy. Our study showed that the 1-L PEG-Asc plus bisacodyl preparation has comparable tolerability and results in adequate colon cleansing. Bowel preparation with bisacodyl and 1-L PEG-Asc is a suitable alternative to low-volume bowel preparation for colonoscopy. (Clinical trial registration number: NCT02980562.).

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.

Comparison of Two Intensive Bowel Cleansing Regimens in Patients With Previous Poor Bowel Preparation: A Randomized Controlled Study

OBJECTIVES

Inadequate bowel cleansing is a major burden for endoscopy units. The aim of this study was to compare two intensive bowel cleansing regimens in patients with previous colonoscopy with inadequate bowel preparation.

METHODS

Patients with inadequate cleansing at index colonoscopy were randomized to 4-L split-dose polyethylene-glycol (PEG) regimen vs. 2-L split-dose PEG plus ascorbic acid (PEG+Asc) regimen. All individuals underwent a 3-day low-residue diet and received 10 mg of bisacodyl, the day before colonoscopy. Cleansing was considered to be adequate if the Boston Bowel Preparation Scale scored ≥2 at each colonic segment. A non-inferiority analysis was performed to demonstrate that colonic cleansing with 2-L PEG+Asc was not inferior to 4-l PEG, considering a non-inferiority margin of 10%.

RESULTS

Adequate bowel cleansing was significantly higher in patients assigned to 4-L PEG regimen (n=127) vs. those randomized to 2-L PEG+Asc regimen (n=129) by intention-to-treat analysis (81.1 vs. 67.4%, odds ratio (OR) 2.07, 95% confidence interval (CI) (1.163-3.689)) and by per-protocol analysis (86.6 vs. 71.7%, OR: 2.55, 95% CI: (1.316-4.922)). The study was terminated for futility after the interim analysis, because the 95% CI of the difference of proportions was 3.13-24.27% in the intention-to-treat analysis and 3.33-26.47% in the per-protocol analysis, confirming the superiority of 4-L PEG preparation.

CONCLUSIONS

After 3-day low-residue diet and oral bisacodyl before colonoscopy, colon cleansing with 4-L split-dose PEG was superior to 2-L split-dose PEG+Asc in patients with previous inadequate cleansing. (EUDRACT: 2013-002506-31, NCT02073552).

Comparative Evaluation of the Efficacy of Polyethylene Glycol With Ascorbic Acid and an Oral Sulfate Solution in a Split Method for Bowel Preparation: A Randomized, Multicenter Phase III Clinical Trial

BACKGROUND

An adequate level of bowel preparation before colonoscopy is important. The ideal agent for bowel preparation should be effective and tolerable.

OBJECTIVE

The purpose of this study was to compare the clinical efficacy and tolerability of polyethylene glycol with ascorbic acid and oral sulfate solution in a split method for bowel preparation.

DESIGN

This was a prospective, multicenter, randomized controlled clinical trial.

SETTINGS

Outpatients at the specialized clinics were included.

PATIENTS

A total of 186 subjects were randomly assigned. After exclusions, 84 subjects in the polyethylene glycol with ascorbic acid group and 83 subjects in the oral sulfate solution group completed the study and were analyzed.

INTERVENTIONS

Polyethylene glycol with ascorbic acid or oral sulfate solution in a split method was the included intervention.

MAIN OUTCOME MEASURES

The primary end point was the rate of successful bowel preparation, which was defined as being excellent or good on the Aronchick scale. Tolerability and adverse events were also measured.

RESULTS

Success of bowel preparation was not different between 2 groups (91.7% vs 96.4%; p = 0.20), and the rate of adverse GI events (abdominal distension, pain, nausea, vomiting, or abdominal discomfort) was not significantly different between the 2 groups. In contrast, the mean intensity of vomiting was higher in the oral sulfate solution group than in the polyethylene glycol with ascorbic acid group (1.6 ± 0.9 vs 1.9 ± 1.1; p = 0.02).

LIMITATIONS

All of the colonoscopies were performed in the morning, and the subjects were offered enhanced instructions for bowel preparation. In addition, the results of tolerability and adverse effect may have a type II error, because the number of cases was calculated for confirming the efficacy of bowel preparation.

CONCLUSIONS

Oral sulfate solution is effective at colonoscopy cleansing and has acceptable tolerability when it is compared with polyethylene glycol with ascorbic acid. The taste and flavor of oral sulfate solution still need to be improved to enhance tolerability.

Safety and Efficacy of a Same-Day Low-Volume 1 L PEG Bowel Preparation in Colonoscopy for the Elderly People and People with Renal Dysfunction

INTRODUCTION

A same-day low-volume 1 L polyethylene glycol (PEG) for bowel preparation before colonoscopy was developed to improve patients' compliance. We aimed to evaluate the efficacy and safety of this regimen especially for the elderly and patients with renal dysfunction.

METHODS

All consecutive patients who underwent colonoscopy in our center from November 2014 to September 2015 were included. Patients undertook a low-residue diet with 10 mL sodium picosulfate 1 day before colonoscopy. Subsequently, they had 1 L low-volume PEG (MoviPrep) and 0.5 L water 4 h before the examination. Clinical outcomes, including cleansing level using the Boston bowel preparation score (BBPS), in the elderly and special-elderly (65-79 and ≥80 years old) were analyzed and compared with the non-elderly (18-64 years old). Additionally, patients with renal dysfunction were analyzed with respect to both complications and changes in blood parameters.

RESULTS

A total of 5427 patients (mean age: 64.5 ± 13.8) were analyzed. The rate of BBPS ≥ 6 in the elderly (2761 patients), special-elderly (565 patients), and non-elderly (2101 patients) was 94.1, 91.8, and 94.6 %, respectively. In the special-elderly, the rate of renal dysfunction was 14.8 %, and no severe complications were detected after colonoscopy. Additionally, there were no severe complications in 86 patients with renal dysfunction, though elevation of hematocrit was shown after intake of 1 L PEG (before, 36.7 ± 6.1 vs. after, 39.0 ± 5.7, P = 0.006).

CONCLUSIONS

Our study shows the safety and efficacy of same-day low-volume 1 L PEG bowel preparation in colonoscopy for the elderly and patients with renal dysfunction.

Does 2 L Polyethylene Glycol Plus Ascorbic Acid Increase the Risk of Renal Impairment Compared to 4 L Polyethylene Glycol?

BACKGROUND

The use of polyethylene glycol (PEG)-based solutions is the gold standard for bowel preparation. However, PEG use might be associated with the risk of acute kidney injury.

AIMS

We aimed to compare the safety of 2 L PEG plus ascorbic acid (AA) versus 4 L PEG.

METHODS

Health examinees that underwent colonoscopy and blood tests on the same day at our center were included in this retrospective study. All subjects were prescribed either 2 L PEG plus AA or 4 L PEG for the bowel preparation prior to the colonoscopy. The incidences of electrolyte imbalance and renal impairment after colonic preparation were investigated. Renal impairment was determined if the subject's estimated glomerular filtration rate was measured less than 60 mL/min/1.73 m².

RESULTS

Of the 29,789 cases, 14,790 received 2 L PEG plus AA (group A) and 14,999 received 4 L PEG (group B) for colonic preparation. Renal impairment occurred more commonly in group A (n = 467, 3.2 %) than in group B (n = 189, 1.3 %). Electrolyte changes such as hypernatremia and hyperkalemia were more common in group A than group B, whereas hyponatremia, hypokalemia, and hypophosphatemia were more common in group B than group A. Old age, male sex, and the use of 2 L PEG plus AA were independent risk factors for renal impairment.

CONCLUSIONS

The evidence strongly suggests that acute kidney injury is more likely to occur when 2 L PEG plus AA is used for the bowel preparation than when 4 L PEG is used.

CLINICAL TRIAL REGISTRATION NUMBER

KCT0001703.

Addition of Lubiprostone to polyethylene glycol(PEG) enhances the quality & efficacy of colonoscopy preparation: a randomized, double-blind, placebo controlled trial

Background

Adequate bowel preparation is an essential prerequisite for complete mucosal visualization during colonoscopy. Polyethylene glycol (PEG) solutions are commonly used. However the large volume of the solution is often poorly tolerated. Addition of Lubiprostone (LB) could improve the adequacy of standard PEG preparation & reduce requirement. The aims to assess adequacy of PEG preparation with addition of single dose LB (24mcg) vs placebo and efficacy of reduced dose PEG + LB compared with full dose PEG + LB.

Methods

Single center prospective double blind randomized controlled trial. Part I: 442 patients for colonoscopy randomized to receive placebo (GrA) or single dose of LB (GrB) prior to PEG preparation. Quality of bowel preparation graded 0–9 according to Boston Bowel Preparation Scale (BBPS). BBPS-9: excellent and BBPS 0–4: repeat procedure.

Part II: 146 patients randomized to receive LB + 1.5 L PEG (GrC; 75) or LB + 1 L PEG (GrD; 71). BBPS score compared with GrB (2 L PEG).

Results

Part I: 442 patients (221 GrA & 221 Gr B). LB resulted in significant improvement in total BBPS (7.44 + 0.14 vs. 6.36 + 0.16, p < 0.0001). 66.5 % Gr B vs 38 % Gr A had excellent prep; 42.5 % GrB vs 24 % GrA had adequate prep. Repeat procedure needed 9.5 % Gr B vs 16.7 % Gr A (P < 0.01).

Part II: No difference in BBPS scores with lower doses (Gr C&D) compared to standard (GrB) (Mean BBPS 7.44 + 0.14 GrA,7.30 + 0.25 GrC;7.25 + 0.26 GrD;p >0.05).

Conclusion

Single dose LB prior to PEG significantly enhanced bowel preparation compared to PEG alone. There was no significant difference in quality of preparation with lower doses of PEG when combined with LB.

Trial registration

The study protocol was approved by institutional review board and the trial was registered on March 22, 2011 with clinicaltrials.gov (NCT01324284).

Polyethylene glycol plus ascorbic acid for bowel preparation in chronic kidney disease

The safety of polyethylene glycol plus ascorbic acid has not been fully investigated in patients with renal insufficiency. High-dose ascorbic acid could induce hyperoxaluria, thereby causing tubule-interstitial nephritis and renal failure. This study aims to evaluate the safety and efficacy of polyethylene glycol plus ascorbic acid in patients with chronic kidney disease.We retrospectively reviewed prospectively collected data on colonoscopy in patients with impaired renal function. Patients were divided into 2 groups: 2 L polyethylene glycol plus ascorbic acid (n = 61) and 4 L polyethylene glycol (n = 80). The safety of the 2 groups was compared by assessing the differences in laboratory findings before and after bowel cleansing.The laboratory findings were not significantly different before and after the administration of 2 L polyethylene glycol plus ascorbic acid or 4 L polyethylene glycol. In both groups, the estimated glomerular filtration rate was not influenced by the administration of the bowel-cleansing agent. Patients' reports on tolerance and acceptability were better in the 2 L polyethylene glycol plus ascorbic acid group than in the 4 L polyethylene glycol group.The 2 L polyethylene glycol plus ascorbic acid solution is a safe choice for bowel preparation before colonoscopy in patients with impaired renal function.

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.

The use of low-volume polyethylene glycol containing ascorbic acid versus 2 L of polyethylene glycol plus bisacodyl as bowel preparation for colonoscopy

OBJECTIVE

Low-volume polyethylene glycol (PEG) bowel preparations have been developed to improve compliance for colonoscopy. Our study aimed to compare the efficacy and tolerability of low-volume PEG containing ascorbic acid for colonoscopy against 2 L of PEG plus bisacodyl.

METHODS

We prospectively enrolled consecutive inpatients who had not undergone polypectomy at the index colonoscopy and were subsequently referred for polypectomy at our hospital. A total of 62 patients were randomized to receive either low-volume PEG containing ascorbic acid (n = 31) or 2 L of PEG plus bisacodyl (n = 31) as a split-dose regimen in inpatients. The efficacy of preparation was determined using the Ottawa Bowel Preparation Score (OBPS) and a 4-point scale. Adverse events, tolerability, and willingness were evaluated using a questionnaire.

RESULTS

Based on the OBPS and 4-point scale, we determined that the efficacy of low-volume PEG containing ascorbic acid was comparable to that of the 2 L of PEG plus bisacodyl (p = 0.071 for OBPS, p = 0.056 for the 4-point scale). Adverse events were comparable between the two groups (p = 1.000). A greater proportion of patients in the low-volume PEG containing ascorbic acid (90.6%) and the 2L of PEG plus bisacodyl (96.9%) were willing to repeat the same preparation for subsequent colonoscopy.

CONCLUSION

Low-volume PEG containing ascorbic acid had comparable efficacy and tolerability to 2 L of PEG plus bisacodyl, when given as a split dose, for colonoscopy in inpatients. Split-dose low-volume PEG containing ascorbic acid is a good alternative for bowel preparation for colonoscopy in inpatients.

Simethicone to prevent colonic bubbles during CT colonography performed with polyethylene glycol lavage and iohexol tagging: a randomized clinical trial

OBJECTIVE

The purpose of this study was to determine whether the occurrence of numerous colonic bubbles during CT colonography (CTC) performed with polyethylene glycol cleansing and oral iohexol fecal/fluid tagging could be prevented by use of simethicone.

SUBJECTS AND METHODS

Adults with suspected colonic neoplasia who had been randomly assigned to control and simethicone intervention groups underwent CTC after cleansing with 4 L of polyethylene glycol, tagging with 50 mL of 350 mg I/mL oral iohexol, and without (control) or with (intervention) oral administration of 200 mg of simethicone. Colonic segments in the control and intervention groups were evaluated for amount of colonic bubbles during CTC. A 6-point grading system was used in which 0 indicated no bubbles and 5 indicated that more than three fourths of the air-distended mucosa was covered with bubbles. The primary endpoint was a per-patient colonic bubble grade, derived as an average of the segmental grades.

RESULTS

Eighty adults with suspected colonic neoplasia were randomly assigned to the control (40 patients) and simethicone intervention (40 patients) groups. A total of 659 colonic segments in the control group and 689 segments in the intervention group were evaluated for amount of colonic bubbles during CTC. The per-patient colonic bubble score was significantly lower in the simethicone intervention group than in the control group. The mean score was 0.0±0.1 (SD) versus 1.2±0.8 (p<0.001; 95% CI for the mean difference, -1.4 to -1.0). In the intervention group, 673 (97.7%) segments were grade 0, and 16 (2.3%) were grade 1. In contrast, in the control group, 226 (34.3%) segments were grade 0; 173 (26.3%), grade 1; 175 (26.6%), grade 2; 45 (6.8%), grade 3; 23 (3.5%), grade 4; and 17 (2.6%), grade 5.

CONCLUSION

The colonic bubbles associated with fecal/fluid tagging with iohexol can be successfully prevented by adding simethicone to the colonic preparation.

Electrolyte changes after bowel preparation for colonoscopy: A randomized controlled multicenter trial

AIM: To investigate the electrolyte changes between 2-L polyethylene glycol with ascorbic acid 20 g (PEG-Asc) and 4-L PEG solutions.

METHODS: From August 2012 to February 2013, a total of 226 patients were enrolled at four tertiary hospitals. All patients were randomly allocated to a PEG-Asc group or a 4-L PEG. Before colonoscopy, patients completed a questionnaire to assess bowel preparation-related symptoms, satisfaction, and willingness. Endoscopists assessed the bowel preparation using the Boston Bowel Preparation Scale (BBPS). In addition, blood tests, including serum electrolytes, serum osmolarity, and urine osmolarity were evaluated both before and after the procedure.

RESULTS: A total of 226 patients were analyzed. BBPS scores were similar and the adequate bowel preparation rate (BBPS ≥ 6) was not different between the two groups (PEG-Asc vs 4-L PEG, 73.2% vs 76.3%, P = 0.760). Bowel preparation-related symptoms also were not different between the two groups. The taste of PEG-Asc was better (41.1% vs 16.7%, P < 0.001), and the willingness to undergo repeated bowel preparation was higher in the PEG-Asc group (73.2% vs 59.3%, P = 0.027) than in 4-L PEG. There were no significant changes in serum electrolytes in either group.

CONCLUSION: In this multicenter trial, bowel preparation with PEG-Asc was better than 4-L PEG in terms of patient satisfaction, with similar degrees of bowel preparation and electrolyte changes.

Iohexol versus diatrizoate for fecal/fluid tagging during CT colonography performed with cathartic preparation: comparison of examination quality

OBJECTIVE

We aimed to compare iohexol vs. diatrizoate as fecal/fluid tagging agents for computed tomography colonography (CTC) regarding examination quality.

METHODS

Forty prospective patients (M:F = 23:17; 63 ± 11.6 years) received CTC using 50 mL (350 mgI/mL) oral iohexol for tagging. Forty other indication-matched, age-matched, and sex-matched patients who underwent CTC using 100 mL diatrizoate for tagging and otherwise the same technique, were retrospectively identified. Two groups were compared regarding overall examination quality, per-patient and per-segment scores of colonic bubbles (0 [no bubbles] to 5 [the largest amount]), and the volume, attenuation, and homogeneity (untagged, layered, and homogeneous) of the residual colonic fluid.

RESULTS

The iohexol group demonstrated a greater amount of colonic bubbles than the diatrizoate group: mean per-patient scores ± SD of 1.2 ± 0.8 vs. 0.7 ± 0.6, respectively (p = 0.003); and rates of segments showing ≥ grade 3 bubbles of 12.9 % (85/659) vs. 1.6 % (11/695), respectively (p = 0.001). Residual colonic fluid amount standardized to the colonic volume did not significantly differ: 7.2 % ± 4.2 vs. 7.8 % ± 3.7, respectively (p = 0.544). Tagged fluid attenuation was mostly comparable between groups and the fluid was homogeneously tagged in 98.7 % (224/227) vs. 99.5 % (218/219) segments, respectively (p = 0.344). Iohexol caused more colonic bubbles when used during cathartic CTC. Otherwise, examination quality was similarly adequate with both iohexol and diatrizoate.

KEY POINTS

• When used for tagging, iohexol caused significantly more colonic bubbles than diatrizoate. • The residual colonic fluid amount did not significantly differ between iohexol and diatrizoate. • The quality of fluid tagging was similarly adequate in both iohexol and diatrizoate.

Achieving the best bowel preparation for colonoscopy

Bowel preparation is a core issue in colonoscopy, as it is closely related to the quality of the procedure. Patients often find that bowel preparation is the most unpleasant part of the examination. It is widely accepted that the quality of cleansing must be excellent to facilitate detecting neoplastic lesions. In spite of its importance and potential implications, until recently, bowel preparation has not been the subject of much study. The most commonly used agents are high-volume polyethylene glycol (PEG) electrolyte solution and sodium phosphate. There has been some confusion, even in published meta-analyses, regarding which of the two agents provides better cleansing. It is clear now that both PEG and sodium phosphate are effective when administered with proper timing. Consequently, the timing of administration is recognized as one of the central factors to the quality of cleansing. The bowel preparation agent should be administered, at least in part, a few hours in advance of the colonoscopy. Several low volume agents are available, and either new or modified schedules with PEG that usually improve tolerance. Certain adjuvants can also be used to reduce the volume of PEG, or to improve the efficacy of other agents. Other factors apart from the choice of agent can improve the quality of bowel cleansing. For instance, the effect of diet before colonoscopy has not been completely clarified, but an exclusively liquid diet is probably not required, and a low-fiber diet may be preferable because it improves patient satisfaction and the quality of the procedure. Some patients, such as diabetics and persons with heart or kidney disease, require modified procedures and certain precautions. Bowel preparation for pediatric patients is also reviewed here. In such cases, PEG remains the most commonly used agent. As detecting neoplasia is not the main objective with these patients, less intensive preparation may suffice. Special considerations must be made for patients with inflammatory bowel disease, including safety and diagnostic issues, so that the most adequate agent is chosen. Identifying neoplasia is one of the main objectives of colonoscopy with these patients, and the target lesions are often almost invisible with white light endoscopy. Therefore excellent quality preparation is required to find these lesions and to apply advanced methods such as chromoendoscopy. Bowel preparation for patients with lower gastrointestinal bleeding represents a challenge, and the strategies available are also reviewed here.

[Bowel preparation for colonoscopy. Any significant progress on the horizon?]

Colonoscopy is the method of choice for colorectal cancer screening. To be effective, screening colonoscopy must have high quality standards. The key element is the quality of the preparation. However, up to 20% of patients are inadequately prepared and, at present, anterograde washing is the least tolerated part of the procedure. In the choice of preparation, safety is a prerequisite and efficacy is a priority. Tolerance is a secondary but nevertheless influential factor in the quality of preparation and has consequently been the primary focus of many recent studies. In the last few years, a rapidly increasing number of studies have evaluated new drugs, dosages and adjuvant therapies to improve efficacy and tolerability. These studies have collaterally shown that inadequate preparation and lack of adherence to the prescribed regimen can be partially predicted, making it essential to identify this patient subgroup and invest the necessary effort in their instruction. New individualized and flexible approaches are expected for the different clinical scenarios. The search for the ideal colonoscopy preparation, which would be tolerable, safe and above all effective, remains open.

Randomized, controlled trial of 2 L polyethylene glycol plus ascorbate components versus sodium phosphate for bowel cleansing prior to colonoscopy for cancer screening

BACKGROUND

Colonoscopy requires effective bowel preparation for adequate mucosal visualization. Safety and acceptability of bowel preparation are key components in colorectal cancer screening (CRC) populations.

OBJECTIVE

To compare the efficacy, safety and acceptability of bowel preparation with polyethylene glycol (PEG), ascorbic acid, sodium ascorbate (ascorbate components), sodium sulfate and electrolytes (PEG+Asc) or sodium phosphate (NaP).

METHODS

Consenting adults undergoing elective out-patient colonoscopy for CRC were randomized to take 2 L PEG+Asc or 90 mL NaP (control) following manufacturer's instructions. PEG+Asc was taken the evening before and morning of the colonoscopy; NaP was taken the morning and evening before colonoscopy. Participants followed a restricted diet specific to each preparation. Primary endpoint was bowel cleansing success (100% colon mucosa visible) rated by an independent expert panel (all experienced endoscopists) unaware of treatment allocations. Subject reported outcomes about the preparations were elicited. Adverse events were recorded.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT00427089.

RESULTS

Successful bowel cleansing rate was significantly higher in the PEG+Asc (N = 242) than the NaP (N = 114) group (PEG+Asc 93.4% [95% CI 89.5-96.2] versus NaP 22.8% [15.5-31.6%], p < 0.0001). Subject reported outcomes on acceptability of the two different preparations were not significantly different (p = 0.238). However, taste ratings for PEG+Asc were significantly better versus NaP (mean VAS: 31.2 and 38.1 respectively, p = 0.0111). The proportion of patients prepared to receive the same preparation again was significantly higher in the PEG+Asc group (88.4% vs. 78.1%, p < 0.0001).

CONCLUSIONS

PEG+Asc provided superior bowel cleansing to NaP and was well tolerated. Findings for PEG+Asc are aligned with previous similar studies; however, differences observed in NaP cleansing results, especially for the proximal colon segments, may be due to factors including: differences in demographics and population types and the use of the validated Harefield Cleansing Scale as an assessment tool combined with expert reviews, which may have resulted in conservative cleansing assessments.

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.

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.