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

Comparison of optimal bowel cleansing effects of 1L polyethylene glycol with ascorbic acid versus sodium picosulfate with magnesium citrate: A randomized controlled study

Various low-volume bowel cleansing formulations that improve compliance have been approved and are being used in clinical practice. This study aimed to compare the effectiveness of 1 L polyethylene glycol (PEG) with ascorbic acid with that of sodium picosulfate (PICO) with magnesium citrate. This was a multicenter, randomized controlled, non-inferiority study. Patients were randomized into a 1 L PEG with ascorbic acid group and a PICO with magnesium citrate group according to the bowel cleansing agent used. Colonoscopy was performed as a single-blind study wherein the endoscopist had no information about any bowel preparation agent. The efficacy of bowel cleansing was assessed using the Harefield Cleansing Scale (HCS), and adverse events, preferences, and satisfaction were evaluated using a patient-reported questionnaire before colonoscopy. A total of 254 participants were randomly assigned to two groups: 115 in the 1 L PEG with ascorbic acid group and 113 in the PICO with magnesium citrate group. Overall bowel cleansing success was not statistically different between the two groups (97.4 vs. 97.3%), confirming that 1 L PEG with ascorbic acid was not inferior to PICO with magnesium citrate (lower confidence limit, -4.15%; p = 1.00). High-quality bowel cleansing was achieved in 87% of the 1 L PEG with ascorbic acid group and 77% of the PICO with magnesium citrate group (Lower confidence limit, 1.29%, p = 0.05). In terms of patient satisfaction, PICO with magnesium citrate was better, but compliance and side effects were similar in both groups. The 1 L PEG with ascorbic acid showed similar efficacy and adverse events as PICO with magnesium citrate. Although 1 L PEG with ascorbic acid is very effective in bowel preparation despite its small volume, it is necessary to increase satisfaction such as taste and feeling.

Same-day single-dose vs large-volume split-dose regimens of polyethylene glycol for bowel preparation: A systematic review and meta-analysis

BACKGROUND

Split-dose regimens (SpDs) of 4 L of polyethylene glycol (PEG) have been established as the “gold standard” for bowel preparation; however, its use is limited by the large volumes of fluids required and sleep disturbance associated with night doses. Meanwhile, the same-day single-dose regimens (SSDs) of PEG has been recommended as an alternative; however, its superiority compared to other regimens is a matter of debate.

AIM

To compare the efficacy and tolerability between SSDs and large-volume SpDs PEG for bowel preparation.

METHODS

We searched MEDLINE/PubMed, the Cochrane Library, RCA, EMBASE and Science Citation Index Expanded for randomized trials comparing (2 L/4 L) SSDs to large-volume (4 L/3 L) SpDs PEG-based regimens, regardless of adjuvant laxative use. The pooled analysis of relative risk ratio and mean difference was calculated for bowel cleanliness, sleep disturbance, willingness to repeat the procedure using the same preparation and adverse effects. A random effects model or fixed-effects model was chosen based on heterogeneity analysis among studies.

RESULTS

A total of 18 studies were included. There was no statistically significant difference of adequate bowel preparation (relative risk = 0.97; 95%CI: 0.92-1.02) (14 trials), right colon Boston Bowel Preparation Scale (mean difference = 0.00; 95%CI: -0.04, 0.03) (9 trials) and right colon Ottawa Bowel Preparation Scale (mean difference = 0.04; 95%CI: -0.27, 0.34) (5 trials) between (2 L/4 L) SSDs and large-volume (4 L/3 L) SpDs, regardless of adjuvant laxative use. The pooled analysis favored the use of SSDs with less sleep disturbance (relative risk = 0.52; 95%CI: 0.40, 0.68) and lower incidence of abdominal pain (relative risk = 0.75; 95%CI: 0.62, 0.90). During subgroup analysis, patients that received low-volume (2 L) SSDs showed more willingness to repeat the procedure using the same preparation than SpDs (P < 0.05). No significant difference in adverse effects, including nausea, vomiting and bloating, was found between the two arms (P > 0.05).

CONCLUSION

Regardless of adjuvant laxative use, the (2 L/4 L) SSD PEG-based arm was considered equal or better than the large-volume (≥ 3 L) SpDs PEG regimen in terms of bowel cleanliness and tolerability. Patients that received low-volume (2 L) SSDs showed more willingness to repeat the procedure using the same preparation due to the low-volume fluid requirement and less sleep disturbance.

The Bowel CLEANsing National Initiative: High-Volume Split-Dose Vs Low-Volume Split-Dose Polyethylene Glycol Preparations: A Randomized Controlled Trial

BACKGROUND & AIMS

The aim of this study was to compare high-volume polyethylene glycol (PEG) with low-volume PEG with bisacodyl split-dosing regimens.

METHODS

Adult outpatients in 10 Canadian tertiary hospitals were randomized, stratified by morning or afternoon colonoscopy, to high-volume split-dose PEG (2 L + 2 L) (High-SD) or low volume (1 L + 1 L) + bisacodyl (15 mg) PEG (Low-SD), with a second randomization to liquid or low-residue diets. The primary end point, using noninferiority hypothesis testing, was adequate bowel cleansing (Boston Bowel Preparation Scale total score of ≥6, with each of 3 colonic segments subscores ≥2). Secondary objectives were willingness to repeat the preparation, withdrawal time, cecal intubation, and polyp detection rates.

RESULTS

Over 29 months, 2314 subjects were randomized to High-SD (N = 1157) or Low-SD (N = 1157) (mean age, 56.2 ± 13.4 y; 52.1% women). Colonoscopy indications were 38.2% diagnostic, 36.8% screening, and 25.0% surveillance, with no between-group imbalances in patient characteristics. Low-SD satisfied noninferiority criteria vs High-SD for adequate bowel cleanliness with only marginally inferior results (90.1% vs 88.1%; P = .02; difference, 2.0%; 95% CI [0.0%; 4.5%]). High-SD was associated with lower willingness to repeat (66.9% vs 91.9%; P < .01), was less well tolerated (7.3 ± 2.3 vs 8.1 ± 1.9; P < .01), causing more symptoms. No differences in procedural outcomes were noted except for more frequent cecal intubation rates after High-SD (97.4% vs 95.6%; P = .02). Among the High-SD group, adequate bowel preparation was greater after a clear liquid diet (93.6% vs 87.9%; P < .01), a finding not seen in the Low-SD group.

CONCLUSIONS

Low-SD is noninferior to High-SD in providing adequate bowel preparation. Low-SD results in fewer symptoms, with greater willingness to repeat and tolerability. The overall impact of diet was modest.The study was approved by the research ethic boards from all sites and was registered at ClinicalTrials.gov (NCT02547571).

Effectiveness of low-volume split-dose versus same-day morning polyethylene glycol regimen for adequacy of bowel preparation in patients undergoing colonoscopy: A single-blinded randomized controlled trial

BACKGROUND

Successful completion of colonoscopy depends largely on the quality of bowel preparation. Polyethylene glycol (PEG) is a commonly used preparation for colonoscopy. The timing of bowel preparation has evolved from previous day evening to the currently recommended split-dose regimen. It was observed that consumption of entire or a portion of PEG on the previous day can interfere with work and sleep. Hence, we designed this single-blinded randomized controlled trial (RCT) to evaluate the efficacy, tolerability, and acceptability of the same-day PEG as compared with lowvolume split-dose PEG in patients undergoing late morning colonoscopy.

METHODS

A total of 384 patients were randomized to same-day (SD group; n = 192) and split-dose (SPL group; n = 192) bowel preparation. The patients in both the groups received bisacodyl 10 mg at bedtime on the day prior to colonoscopy. The patients in the SD group took 2 L of PEG between 5:00 AM and 7:00 AM on the day of colonoscopy. The SPL group took 1 L of PEG between 6:00 PM and 7:00 PM on the preceding day and another liter between 6:00 AM and 7:00 AM on the day of colonoscopy. The adequacy of bowel preparation was assessed using the Boston Bowel Preparation Scale (BBPS). Tolerability was scored by recording symptoms such as nausea, vomiting, bloating, and abdominal pain. Acceptability was based on the overall satisfaction, willingness to repeat the same preparation, and interference with sleep on the preceding night.

RESULTS

The median (interquartile range, [IQR]) BBPS in the SD group was 8 (6-9) while that in the SPL group was 6 (5-8) and this difference was statistically significant (p < 0.001). Similarly, a significantly higher proportion of patients in the SD group (86%) achieved adequate bowel preparation (BBPS score ≥ 6) when compared to those in the SPL group (73.4%) (p = 0.002). Tolerability as assessed by nausea, vomiting, bloating, and abdominal pain was similar in both the groups. There was also no significant difference with respect to overall satisfaction of taking bowel preparation (p = 0.33) or willingness to repeat the same regimen (p = 0.37) between the two groups. Patients in the SPL group had more interference with sleep on the preceding night (54% vs. 14.5%, p < 0.001).

CONCLUSION

Same-day morning PEG regimen can be considered an effective, well-tolerated, and acceptable bowel preparation for colonoscopy.

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 and safety of oral sulfate solution for bowel preparation in Japanese patients undergoing colonoscopy: Noninferiority-based, randomized, controlled study

OBJECTIVES

To compare the efficacy and safety of oral sulfate solution administered using the same-day dose and the split-dose regimens with those of polyethylene glycol plus ascorbate solution, used for bowel preparation in Japanese patients undergoing colonoscopy.

METHODS

This multicenter (n = 13), randomized, active-controlled, colonoscopist- and image evaluator-blinded, noninferiority study with parallel-group comparison recruited 632 patients from December 2018 to June 2019. Of these, 602 patients were divided into the oral sulfate solution same-day dose group (n = 200); oral sulfate solution split-dose group (n = 202); and polyethylene glycol plus ascorbate same-day dose group (n = 200). Differences in the efficacy rates between the polyethylene glycol plus ascorbate group and each oral sulfate solution group were calculated using the asymptotic method. The safety of the oral sulfate solution was evaluated, based on the occurrence of adverse events and reactions.

RESULTS

Both oral sulfate solution protocols were confirmed as noninferior to the polyethylene glycol plus ascorbate protocol for bowel-cleansing. The occurrence of adverse reactions was significantly lower in the oral sulfate solution same-day dose group than in the polyethylene glycol plus ascorbate group (P = 0.010). The occurrence of adverse reactions was not significantly different between the oral sulfate solution split-dose and the polyethylene glycol plus ascorbate group.

CONCLUSIONS

Oral sulfate solution is not only safe and efficacious but also not inferior to polyethylene glycol plus ascorbate solution (active control). It could be used for bowel preparation in Japanese patients scheduled for colonoscopy (Clinical trial registration number: NCT03794310).

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.

The Bowel CLEANsing National Initiative: A Low-Volume Same-Day Polyethylene Glycol (PEG) Preparation vs Low-Volume Split-Dose PEG With Bisacodyl or High-Volume Split-Dose PEG Preparations-A Randomized Controlled Trial

INTRODUCTION

Bowel cleanliness has been shown to be superior with split-dose vs nonsplit preparations; we aimed to directly assess the poorly characterized comparative efficacies of split-dose vs same-day polyethylene glycol (PEG) regimens.

METHODS

In this study, one of a series of randomized trials performed across 10 Canadian endoscopy units, patients undergoing colonoscopies between 10:30 and 16:30 were allocated to PEG low-volume same-day (15 mg bisacodyl the day before, 2 L the morning of the procedure), low-volume split-dose (15 mg bisacodyl the day before, 1 L + 1 L), or high-volume split-dose (2 L + 2 L). Coprimary endpoints were adequate bowel cleansing based on the Boston Bowel Preparation Scale using in turn different threshold cutoffs.

RESULTS

Overall, 1,750 subjects were randomized equally across the 3 groups, with no differences in adequate bowel cleanliness rates (low-volume same-day, 90.5%; high-volume split-dose, 92.2%; P = 0.34; and low-volume split-dose, 87.9%; P = 0.17) for the Boston Bowel Preparation Scale ≥6 and 2 for each segment. Willingness to repeat the preparation was not significantly different between low-volume same-day (91.0%) and low-volume split-dose (92.5%; P = 0.40) but was greater than the high-volume split-dose (68.9%; P < 0.01). No significant differences were noted for withdrawal time, cecal intubation, or polyp detection rates.

DISCUSSION

In this large randomized trial of PEG regimens, low-volume same-day resulted in similar bowel cleanliness compared with high-volume or low-volume split-dosing. Willingness to repeat and tolerability were superior with low-volume same-day compared with high-volume split-dose and similar to low-volume split-dose.

Efficacy and Patient Tolerability Profiles of Probiotic Solution with Bisacodyl Versus Conventional Cleansing Solution for Bowel Preparation: A Prospective, Randomized, Controlled Trial

Although adequate bowel preparation is essential in screening colonoscopy, patient intolerability to bowel cleansing agents is problematic. Recently, a probiotic mixture solution with bisacodyl emerged to improve patient tolerability. We investigated the efficacy, safety, and patient tolerability profiles of probiotics with bisacodyl versus conventional polyethylene glycol (PEG) solution for bowel preparation for screening colonoscopies in healthy patients in this prospective, randomized, case-control study. In total, 385 volunteers were randomly assigned to receive 2 L of water + 200 mL of probiotic solution (case group, n = 195) or 4 L of PEG solution (control group, n = 190). The efficacy of the bowel cleansing was evaluated using the Ottawa scale system, polyp detection rate, and adenoma detection rate, and the patient tolerability profiles were assessed using a questionnaire. The demographics were not significantly different between groups. When the Ottawa score for each bowel segment was stratified into an adequate vs. inadequate level (Ottawa score ≤ 3 vs. >3), there were no statistical differences between groups in each segment of the colon. There were no significant differences in the polyp and adenoma detection rates between groups (38.42% vs. 32.42, p = 0.30; 25.79% vs. 18.97%, p = 0.11). The case group showed significantly fewer events than the control group, especially nausea, vomiting, and abdominal bloating events. Regarding the overall satisfaction grade, the case group reported significantly more “average” scores (95% vs. 44%, p < 0.001) and were more willing to use the same agents again (90.26% vs. 61.85%, p < 0.001). As patient compliance with bowel preparation agents is associated with an adequate level of bowel cleansing, a probiotic solution with bisacodyl might be a new bowel preparation candidate, especially in patients who show a poor compliance with conventional bowel preparation agents.

A meta-analysis of randomized controlled trials of the addition of lubiprostone to bowel preparation before colonoscopy

AIM

Adequate bowel preparation is essential to the quality of colonoscopy. We performed a meta-analysis to determine the efficacy and safety of the addition of lubiprostone to the bowel preparation process prior to colonoscopy.

METHODS

Online databases, namely, PubMed, MEDLINE and Cochrane Library, were searched for randomized controlled trials that assessed the additive effect of lubiprostone on the quality of colon preparation in patients undergoing colonoscopy. Each included study was evaluated by the Jadad score to assess the quality of the study. The primary outcome was bowel preparation efficacy, defined as the proportion of patients with an excellent or poor preparation. The secondary outcomes included the length of the colonoscopy, polyp detection, and any adverse effects.

RESULTS

In total, 5 articles published between 2008 and 2016 fulfilled the selection criteria. The addition of lubiprostone to the bowel cleansing process significantly increased the proportion of patients with an excellent preparation (risk ratio [RR] = 1.68, 95% confidence interval (CI): 1.40-2.02, P < .00001) but did not decrease the procedural time or increase the polyp detection rate (mean difference = -0.52, 95% CI: -3.74-2.69, P = .75; RR = 1.16, 95% CI: 0.96-1.42, P = .13, respectively). There was no significant difference in the proportion of patients with any adverse events.

CONCLUSION

The addition of lubiprostone to the bowel preparation regimen prior to colonoscopy is effective and safe.

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.).

Randomized, double-blinded, placebo-controlled trial evaluating simethicone pretreatment with bowel preparation during colonoscopy

BACKGROUND

The presence of small air bubbles and foam are an impediment to a successful colonoscopy. They impair an endoscopist’s view and diminish the diagnostic accuracy of the study. This has been particularly noted to be of concern with the switch to lower volume polyethylene glycol (PEG) and bisacodyl combination preparation.

AIM

To evaluate the effect of oral simethicone addition to bowel preparation on intraluminal bubbles reduction during colonoscopy.

METHODS

Described is a prospective, randomized, multi-center, double-blinded, placebo-controlled study to evaluate the use of premixed simethicone formulation with split-regimen, low-volume PEG-bisacodyl combination bowel preparation for 168 outpatients undergoing screening, surveillance, and diagnostic colonoscopies. Primary outcome includes evaluation of bubbles during colonoscopy graded using the Intraluminal Bubbles Scale. Secondary outcomes include evaluation of the Boston Bowel Preparation Scale (BBPS), total number of polyps, polyp size differentiation, polyp laterality, adenoma detection, mass detection, cecal insertion time, withdrawal time, and patient-reported adverse events.

RESULTS

Higher Intraluminal Bubbles grades III and IV (less than 75% of the mucosa cleared of bubbles/foam requiring intervention with simethicone infused wash) were detected in the placebo group [Simethicone n = 4/84 vs Placebo n = 20/84 (P = 0.007)]. BBPS total score was 7.42 [standard deviation (SD) = ± 1.51] in the simethicone group and 7.28 (SD = ± 1.44) in the placebo group (P = 0.542) from a total of 9. Significantly higher number of adenomas were detected in the simethicone group (P = 0.001).

CONCLUSION

The addition of simethicone to bowel preparation is well advised for its anti-foaming properties. The results of this study suggest that addition of oral simethicone can improve bowel wall visibility.

The Efficacy of Split-Dose Bowel Preparations for Polyp Detection: A Systematic Review and Meta-Analysis

INTRODUCTION

Split-dose bowel preparation leads to superior colon cleansing for colonoscopy. However, the magnitude of benefit in detecting colonic polyps is uncertain. We performed a systematic review to synthesize the data on whether using a split-dose bowel preparation regimen improves the detection of polyps when compared with other dosing methods or regimen products.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL databases (from the inception to June 2017) for randomized controlled trials that assessed the following: split-dose vs day-before, split-dose vs same-day (as colonoscopy), or different types of split-dose regimens for patients undergoing colonoscopy. We excluded studies limited to inpatients, children, or individuals with inflammatory bowel disease. We compared the number of patients undergoing colonoscopy with recorded detection of polyps, adenomas, advanced adenomas, sessile serrated polyps (SSPs), right colonic adenomas, right colonic polyps, or right colonic SSPs.

RESULTS

Twenty-eight trials fulfilled the inclusion criteria (8,842 participants). Of the seven trials comparing split-dose vs day-before bowel preparation regimens, there was an increased detection rate of adenomas (risk ratio (RR) 1.26, 95% confidence intervals (CIs): 1.10-1.44; 4 trials; 1,258 participants), advanced adenomas (RR 1.53, 95% CI: 1.22-1.92; 3 trials; 1,155 participants), and SSPs (RR 2.48, 95% CI: 1.21-5.09; 2 trials; 1,045 participants). Pooled estimates from 8 trials (1,587 participants) evaluating split-dose vs same-day bowel preparations yielded no evidence of statistical difference. For various split-dose vs split-dose trials, 14 fulfilled the criteria (5,496 participants) and no superior split-regimen was identified.

CONCLUSIONS

Compared with day-before bowel preparation regimens, split-dose bowel preparations regimens increase the detection of adenomas, advanced adenomas, and have the greatest benefit in SSP detection.

The benefit of adding oral simethicone in bowel preparation regimen for the detection of colon adenoma: A systematic review and meta-analysis

BACKGROUND AND AIM

Simethicone is an anti-foaming agent commonly used during colonoscopy. Although several randomized trials have shown that oral simethicone in the bowel preparation regimen may improve bowel cleanness, whether it improves adenoma detection rate (ADR) or polyp detection rate remains undetermined. The aim of this study was to determine if oral simethicone in bowel preparation regimen before colonoscopy improves the ADR.

METHODS

A comprehensive literature review was conducted using PubMed, SDOL, Cochrane Library, and ProQuest databases through December 2017. Randomized controlled trials that compared bowel preparation regimens with simethicone versus those without it were included. Effect estimates from each study were extracted and underwent meta-analysis using appropriate models. The primary outcomes were ADR and polyp detection rate, and secondary outcomes included bowel preparation, bubble score, and withdrawal time.

RESULTS

Twelve published randomized controlled studies with 6003 participants were included for meta-analysis. There was no difference in the overall ADR (pooled risk ratio = 1.06, 95% confidence interval = 0.91-1.24) and right-side ADR (risk ratio = 1.50, 95% confidence interval = 0.82-2.75) between the groups with or without simethicone. However, the addition of simethicone improved adenoma detected per patient (2.20 ± 1.36 vs 1.63 ± 0.89) according to one of the included studies. Meta-regression revealed that the baseline ADR < 25% of the included studies was associated with significant benefit of oral simethicone; the number needed to treat was 15.

CONCLUSIONS

The adjunction of oral simethicone significantly improved bowel preparation quality and might benefit adenoma detection in specific settings with low baseline ADR.

Same-Day Regimen as an Alternative to Split Preparation for Colonoscopy: A Systematic Review with Meta-Analysis

Background

Split bowel preparation is the best regimen for colonoscopy. However, the same-day regimen can represent a valid alternative, but its use is limited by concerns about its cleansing ability, and to date, no convincing data support its use for routine colonoscopies.

Aim

To evaluate the cleansing, compliance, and adverse event rates of the same-day compared to the split regimen.

Results

A systematic literature search and meta-analysis was performed. Ten studies were included for a total of 1807 patients (880 in the same-day group and 927 in the split group). Overall, 85.3% patients in the same-day group vs. 86.3% in the split group had an adequate cleansing. Compliance was high for both, although patients were more compliant with the split than with the same-day prep (89.7% for same-day vs. 96.6% for split regimen). Sleep disturbance was more frequent in the split group, while nausea and vomit were more frequent in the same-day group. In the subgroup analysis, polyethylene glycol obtained a better cleansing rate when given as a split dose, with similar compliance and adverse events rates with both regimens.

Conclusion

Split and same-day regimens are both useful in bowel cleaning before colonoscopy with a different pattern of adverse events and better compliance for split preparations. Endoscopists can consider the same-day preparation as a valid alternative, especially when the split preparation does not fit the patients' needs.

Effect of supplemental simethicone for bowel preparation on adenoma detection during colonoscopy: A meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Although several randomized controlled trials (RCTs) have reported that supplemental simethicone (SIM) can improve bowel preparation based on polyethylene glycol, there is no consensus as to whether SIM can ultimately increase the adenoma detection rate (ADR) during colonoscopy. A meta-analysis was performed to assess the effect of SIM on ADR during colonoscopy.

METHODS

Databases including PubMed, EMBASE, and the Cochrane Library were searched to find relevant RCTs. RCTs evaluating the effect of pre-procedure SIM on the ADR during colonoscopy were finally included, and fixed effect models were applied.

RESULTS

Six trials involving 1855 patients were finally included. The present meta-analysis suggested that the ADR during colonoscopy was significantly increased by supplemental SIM (27.9% vs 23.3%, P = 0.02), with a relative risk of 1.20 (95% confidence interval 1.03-1.39). Subgroup analysis suggested that supplemental SIM may be more useful to improve ADR during colonoscopy in endoscopic centers with low baseline ADR.

CONCLUSIONS

Supplemental SIM for bowel preparation based on polyethylene glycol is useful to improve the ADR during colonoscopy.

Polyethylene glycol plus bisacodyl: A safe, cheap, and effective regimen for colonoscopy in the South Asian patients

BACKGROUND AND AIM

Data regarding the comparison of colonoscopic preparation regimens are still variable. We aimed to assess the adequacy and tolerability of two bowel preparation regimens for afternoon colonoscopy.

METHODS

In a randomized, investigator-blinded trial, two preparation regimens [4-L split-dose polyethylene glycol-electrolytes (PEG-ELS) and 2-L PEG-ELS plus bisacodyl) were compared in terms of bowel cleansing efficacy and adverse effects.

RESULTS

The mean (±SD) age (years) of the 4-L split-dose PEG-ELS group (N = 147) and the 2-L PEG-ELS plus bisacodyl (N = 155) were 44.09 (±15.62) (M:F : 2:1) and 44.12 years (±15.61) (M:F : 1.7:1), respectively. Percentage of patients with excellent and good preparation was higher in the 4-L split-dose PEG-ELS regimen compared with the 2-L PEG-ELS plus bisacodyl regimen (22.44 vs 17.41 and 44.21% vs 36.12%). Percentage of patients with fair and poor preparation was lower in 4-L split-dose PEG-ELS regimen compared with the 2-L PEG-ELS plus bisacodyl regimen (21.08% vs 27.74% and 12.24% vs 18.70%). In comparison with the 2-L PEG-ELS plus bisacodyl group, the incidences of abdominal pain (11% vs 15%), bloating (9% vs 12.24%), nausea/vomiting (8.38% vs 9.52%), and sleep disturbance (11% vs 12%) were slightly more common in the 4-L split-dose PEG-ELS group. There were no statistically significant differences between the two regimens with regard to bowel cleansing efficacy and adverse events.

CONCLUSIONS

The 2-L PEG-ELS plus bisacodyl (10 mg) preparation is as efficacious as the 4-L split-dose PEG-ELS regimen for afternoon colonoscopy. Optimal preparation for colonoscopy can be achieved with the 2-L PEG-ELS plus bisacodyl regimen with slightly fewer adverse events and lower cost compared to the 4-L split-dose PEG-ELS regimen.

Preparation for colonoscopy: Recommendations by an expert panel in Italy

BACKGROUND

Despite several guidelines on bowel preparation being available, their applicability in Italy is poorly investigated.

AIMS

(1) To create expert-based recommendations for the Italian setting based on available international guidelines on bowel preparation for colonoscopy; (2) to assess consensus across the Italian endoscopy community.

METHODS

The study was conducted in 2 phases: (a) statements formulation, (b) assessment of consensus. For the first phase, 6 topics related to bowel preparation were identified: (1) efficacy/tolerability; (2) timing; (3) assessment of quality of bowel preparation; (4) factors associated with inadequate preparation; (5) patient education and (6) impact of organisational factors. For each topic, statements were produced and voted by a panel of experts. For consensus assessment, the invited participants were asked to rate the statements. The statement achieved a good level of agreement when at least 70% of voters agreed with it.

RESULTS

25 statements were agreed in the first phase. Agreement was not achieved by the endoscopy community for 7 statements, mainly concerning practical aspects (i.e. strategies for management of patients with inadequate preparation, organisational factors).

CONCLUSION

A clinically relevant consensus was achieved on the main topics of bowel preparation, such as the choice of laxative and the time of administration, and it may help to homogenize the colonoscopy practice in Italy. Nevertheless, there are a few country-specific preparation-related issues that need to be addressed.

Predictors of patient reluctance to wake early in the morning for bowel preparation for colonoscopy: a precolonoscopy survey in city-wide practice

INTRODUCTION

 Many endoscopists do not use split-dose bowel preparation (SDBP) for morning colonoscopies. Despite SDBP being recommended practice, they believe patients will not agree to take early morning bowel preparation (BP). We assessed patients' opinions about waking early for BP.

METHODS

 A self-administered survey was distributed between 08/2015 and 06/2016 to patients in Winnipeg, Canada when they attended an outpatient colonoscopy. Logistic regression was performed to determine predictors of reluctance to use early morning BP.

RESULTS

 Of the 1336 respondents (52 % female, median age 57 years), 33 % had used SDBP for their current colonoscopy. Of the 1336, 49 % were willing, 24 % neutral, and 27 % reluctant to do early morning BP. Predictors of reluctant versus willing were number of prior colonoscopies (OR 1.20; 95 %CI: 1.07 - 1.35), female gender (OR 1.65; 95 %CI: 1.19 - 2.29), unclear BP information (OR 1.86; 95 %CI: 1.21 - 2.85), high BP anxiety (OR 2.02; 95 %CI: 1.35 - 3.02), purpose of current colonoscopy being bowel symptoms (OR 1.40; 95 %CI: 1.00 - 1.97), use of 4 L of polyethylene glycol laxative (OR 1.45; 95 %CI: 1.02 - 2.06), not having SDBP (OR 1.96; 95 %CI: 1.31 - 2.93), and not having finished the laxative for the current colonoscopy (OR 1.66; 95 %CI: 1.01 - 2.73). Most of the same predictors were identified when reluctance was compared to willing or neutral, and in ordinal logistic regression.

CONCLUSIONS

 Almost three-quarters of patients do not express reluctance to get up early for BP. Among those who are reluctant, improving BP information, allaying BP-related anxiety, and use of low volume BP may increase acceptance of SDBP.

Bowel Preparations Administered the Morning of Colonoscopy Provide Similar Efficacy to a Split Dose Regimen: A Meta Analysis

BACKGROUND

Comparative efficacy of same-day bowel preparations for colonoscopy remains unclear.

AIMS

A meta-analysis of randomized controlled trials comparing the efficacy of same-day versus split dose bowel preparations for colonoscopy.

METHODS

A systematic search was conducted in MEDLINE, clinicaltrials.gov, Cochrane Registry, EMBASE, SCOPUS, Web of Science and CINAHL. Studies were gathered using keywords: "morning preparation", "morning bowel preparation", "same day bowel preparation", and "colonoscopy." Pooled estimates of bowel preparation quality were analyzed among studies with categorical and continuous outcomes according to relative risk (RR) or mean difference (MD). A random effects model was chosen a priori for all analyses.

RESULTS

A total of 1216 studies were retrieved with 15 trials meeting inclusion criteria. The categorical outcome of high quality bowel preparation for any same-day bowel preparation versus any split preparation was no different with a RR 0.95 [0.90;1.00] (P=0.62). Adenoma detection rate (ADR) was not different between groups, RR 0.97 [0.79;1.20] (P=0.81). Willingness to repeat and tolerability did not differ (RR 1.14 [0.96,1.36] (P=0.14) and RR 1.00 [0.96;1.04] (P=0.98), respectively. Adverse events were similar except for bloating, which was less frequent among the same-day preparation group, RR 0.68 [0.40;0.94] (P=0.02).

CONCLUSION

No clinically significant differences were noted among recipients of same day or split dose regimens. Adenoma detection rate, willingness to repeat and tolerability were similar, but bloating and interference with sleep favored the same-day preparations. Given lack of clinical differences, patient preference should dictate timing of colonoscopy preparation.

Cost Effectiveness of Screening Colonoscopy Depends on Adequate Bowel Preparation Rates - A Modeling Study

Background

Inadequate bowel preparation during screening colonoscopy necessitates repeating colonoscopy. Studies suggest inadequate bowel preparation rates of 20–60%. This increases the cost of colonoscopy for our society.

Aim

The aim of this study is to determine the impact of inadequate bowel preparation rate on the cost effectiveness of colonoscopy compared to other screening strategies for colorectal cancer (CRC).

Methods

A microsimulation model of CRC screening strategies for the general population at average risk for CRC. The strategies include fecal immunochemistry test (FIT) every year, colonoscopy every ten years, sigmoidoscopy every five years, or stool DNA test every 3 years. The screening could be performed at private practice offices, outpatient hospitals, and ambulatory surgical centers.

Results

At the current assumed inadequate bowel preparation rate of 25%, the cost of colonoscopy as a screening strategy is above society’s willingness to pay (<$50,000/QALY). Threshold analysis demonstrated that an inadequate bowel preparation rate of 13% or less is necessary before colonoscopy is considered more cost effective than FIT. At inadequate bowel preparation rates of 25%, colonoscopy is still more cost effective compared to sigmoidoscopy and stool DNA test. Sensitivity analysis of all inputs adjusted by ±10% showed incremental cost effectiveness ratio values were influenced most by the specificity, adherence, and sensitivity of FIT and colonoscopy.

Conclusions

Screening colonoscopy is not a cost effective strategy when compared with fecal immunochemical test, as long as the inadequate bowel preparation rate is greater than 13%.

Comparative Study of Three Regimens of Bowel Preparation Before Transabdominal Ultrasonography of the Colon

The objective of the study was to compare the efficacy of three bowel preparation regimens for transabdominal colon ultrasonography. A total of 192 consecutive patients were given one of three regimens (senna, magnesium sulfate or polyethylene glycol electrolyte powder) before ultrasonographic examinations. The cleaning grade (I = emptying; II = filled or filled + empty; III = I or II with some retention; and IV = retention [grades I and II were termed "qualified"]) and cleaning range (A = all seven colon sections were qualified; B = four to six sections were qualified; C = three or less sections were qualified) were evaluated retrospectively. Senna was found more effective than polyethylene glycol in terms of cleaning grade (p < 0.001), qualified rate (p < 0.001) and cleaning range (p = 0.003). Senna was better than magnesium sulfate in cleaning grade (p < 0.001). Our results suggest that senna seems to be the preferred regimen for bowel preparation before transabdominal colonic ultrasonography.

Improving of bowel cleansing effect for polyethylene glycol with ascorbic acid using simethicone: A randomized controlled trial

BACKGROUND AND AIM

Low-volume polyethylene glycol with ascorbic acid (PEG-Asc) use is reported to be as safe and effective as traditional 4-L polyethylene glycol use. However, PEG-Asc produces bubbles, which cause problems during colonoscopy. Data on the effects of using antifoaming agents such as simethicone with PEG-Asc are lacking. The aim of this CONSORT-prospective, randomized, observer-blinded, controlled trial is to compare the quality of bowel preparation and compliance between PEG-Asc users and PEG-Asc plus simethicone users.

METHODS

Adult outpatients aged 18 to 80 years undergoing colonoscopy were recruited to the study. Two hundred sixty patients were randomly assigned to 1 of 2 treatment arms, PEG-Asc or PEG-Asc plus simethicone. The primary outcome measure was the bowel cleansing quality using Boston bowel preparation scale and bubble scores. The secondary outcome measures were patient tolerability and doctor tolerability.

RESULTS

The simethicone group showed superior cleansing results (6-9 Boston scale scores: 99% vs. 84%, <5% bubble scores: 96% vs. 49%, P < 0.001) and fewer gastrointestinal symptoms (abdominal fullness: 24% vs. 55%, colicky pain: 5% vs. 24%, P < 0.001) than the non-simethicone group. Moreover, endoscopist fatigue during colonoscopy was lower in the simethicone group than in the non-simethicone group (1.31 ± 0.75 vs. 2.97 ± 2.14, P < 0.001).

CONCLUSION

PEG-Asc plus simethicone use was more effective and associated with better patient and endoscopist tolerance than PEG-Asc use. Therefore, this combination is recommended as one of the promising methods for bowel preparation before colonoscopy.

Improved bowel preparation increases polyp detection and unmasks significant polyp miss rate

AIM: To retrospectively compare previous-day vs split-dose preparation in terms of bowel cleanliness and polyp detection in patients referred for polypectomy.

METHODS: Fifty patients underwent two colonoscopies: one diagnostic in a private clinic and a second for polypectomy in a University Hospital. The latter procedures were performed within 12 wk of the index ones. Examinations were accomplished by two experienced endoscopists, different in each facility. Twenty-seven patients underwent screening/surveillance colonoscopy, while the rest were symptomatic. Previous day bowel preparation was utilized initially and split-dose for polypectomy. Colon cleansing was evaluated using the Aronchick scale. We measured the number of detected polyps, and the polyp miss rates per-polyp.

RESULTS: Excellent/good preparation was reported in 38 cases with previous-day preparation (76%) vs 46 with split-dose (92%), respectively (P = 0.03). One hundred and twenty-six polyps were detected initially and 169 subsequently (P < 0.0001); 88 vs 126 polyps were diminutive (P < 0.0001), 25 vs 29 small (P = 0.048) and 13 vs 14 equal or larger than 10 mm. The miss rates for total, diminutive, small and large polyps were 25.4%, 30.1%, 13.7% and 6.6%, respectively. Multivariate analysis revealed that split-dose preparation was significantly associated (OR, P) with increased number of polyps detected overall (0.869, P < 0.001), in the right (0.418, P = 0.008) and in the left colon (0.452, P = 0.02).

CONCLUSION: Split-dose preparation improved colon cleansing, enhanced polyp detection and unmasked significant polyp miss rates.

2-Litre polyethylene glycol-citrate-simethicone plus bisacodyl versus 4-litre polyethylene glycol as preparation for colonoscopy in chronic constipation

BACKGROUND

Chronic constipation is a risk factor of inadequate bowel preparation for colonoscopy; however, no large clinical trials have been performed in this subgroup of patients.

AIMS

To compare bowel cleansing efficacy, tolerability and acceptability of 2-L polyethylene-glycol-citrate-simethicone (PEG-CS) plus 2-day bisacodyl (reinforced regimen) vs. 4-L PEG in patients with chronic constipation undergoing colonoscopy.

METHODS

Randomized, observer-blind, parallel group study. Adult outpatients undergoing colonoscopy were randomly allocated to 2-L PEG-CS/bisacodyl or 4-L PEG, taken as split regimens before colonoscopy. Quality of bowel preparation was assessed by the Ottawa Bowel Cleansing Scale (OBCS). The amount of foam/bubble interfering with colonic visualization was also measured.

RESULTS

400 patients were enrolled. There was no significant difference in successful cleansing (OBCS score ≤6): 80.2% in the 2-L PEG-CS/bisacodyl vs. 81.4% in the 4-L PEG group. Significantly more patients taking 2L PEG-CS/bisacodyl showed no or minimal foam/bubbles in all colonic segments (80% vs. 63%; p<0.001). 2-L PEG-CS/bisacodyl was significantly more acceptable for ease of administration (p<0.001), willingness to repeat (p<0.001) and showed better compliance (p=0.002).

CONCLUSION

Split 2-L PEG-CS plus bisacodyl was not superior to split 4-L PEG for colonoscopy bowel cleansing in patients with chronic constipation; however, it performed better than the standard regimen in terms of colonic mucosa visualization, patient acceptance and compliance.

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

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

[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.