The optimal bowel preparation intervals before colonoscopy: A randomized study comparing polyethylene glycol and low-volume solutions

Comparing Low Volume Versus Conventional Volume of Polyethylene Glycol for Bowel Preparation during Colonoscopy: A Randomised Controlled Trial

Background

Polyethylene glycol (PEG) solution is widely used as a colonoscopic bowel cleaning agent, although some patients are intolerant due to the need for ingesting large solution volumes and unpleasant taste. A low-volume solution may enhance patient tolerability and compliance in bowel preparation. Accordingly, this study compared the effectiveness of two difference PEG volumes for bowel preparation before colonoscopy in terms of bowel cleanliness, completeness of colonoscopy, patient tolerability and colonoscopy duration.

Methods

Using a prospective randomised controlled single-blinded study design, 164 patients scheduled for colonoscopy were allocated to two groups (n = 82 patients in each) to receive either the conventional PEG volume (3 L, control group) or the low volume (2 L, intervention group). The Boston Bowel Preparation Scale (BBPS), a validated scale for assessing bowel cleanliness during colonoscopy, was used to score bowel cleanliness in three colon segments. Secondarily, colonoscopy completeness, tolerability to drinking PEG and the duration of colonoscopy were compared between the groups.

Results

There were no statistically significant differences between the two intervention groups in terms of bowel cleanliness (P = 0.119), colonoscopy completion (P = 0.535), tolerability (P = 0.190) or the amount of sedation/analgesia required (midazolam, P = 0.162; pethidine, P = 0.708). Only the duration of colonoscopy differed between the two groups (longer duration in the control group, P = 0.039).

Conclusion

Low-volume (2 L) PEG is as effective as the standard 3 L solution in bowel cleaning before colonoscopy; however, the superiority of either solution could not be established.

Factors affecting the quality of bowel preparation for colonoscopy in hard-to-prepare patients: Evidence from the literature

Adequate bowel cleansing is critical for a high-quality colonoscopy because it affects diagnostic accuracy and adenoma detection. Nevertheless, almost a quarter of procedures are still carried out with suboptimal preparation, resulting in longer procedure times, higher risk of complications, and higher likelihood of missing lesions. Current guidelines recommend high-volume or low-volume polyethylene glycol (PEG)/non-PEG-based split-dose regimens. In patients who have had insufficient bowel cleansing, the colonoscopy should be repeated the same day or the next day with additional bowel cleansing as a salvage option. A strategy that includes a prolonged low-fiber diet, a split preparation regimen, and a colonoscopy within 5 h of the end of preparation may increase cleansing success rates in the elderly. Furthermore, even though no specific product is specifically recommended in the other cases for difficult-to-prepare patients, clinical evidence suggests that 1-L PEG plus ascorbic acid preparation are associated with higher cleansing success in hospitalized and inflammatory bowel disease patients. Patients with severe renal insufficiency (creatinine clearance < 30 mL/min) should be prepared with isotonic high volume PEG solutions. Few data on cirrhotic patients are currently available, and no trials have been conducted in this population. An accurate characterization of procedural and patient variables may lead to a more personalized approach to bowel preparation, especially in patients undergoing resection of left colon lesions, where intestinal preparation has a poor outcome. The purpose of this review was to summarize the evidence on the risk factors influencing the quality of bowel cleansing in difficult-to-prepare patients, as well as strategies to improve colonoscopy preparation in these patients.

Efficacy of ultra-low volume (≤1 L) bowel preparation fluids: Systematic review and meta-analysis

BACKGROUND AND AIMS

High-quality bowel preparation is paramount for the diagnostic accuracy and safety of colonoscopy; however, it is often difficult for patients to adhere to high-volume laxatives, which may contribute to poor bowel preparation. This review aims to assess the efficacy of bowel preparation fluids of 1 L or less (≤1 L).

METHODS

We performed a systematic review including all relevant randomized controlled trials on ultra-low volume (≤1 L) bowel preparation fluids for colonoscopy published since 2015. Primary endpoint was the percentage of adequately prepared patients. Secondary endpoints included adenoma detection rate (ADR) and safety.

RESULTS

Bowel preparation with sodium picosulfate/magnesium citrate (SPMC; 19 trials, n = 10,287), 1L-polyethylene glycol with ascorbate (PEGA; 10 trials, n = 1717), sodium phosphate (NaP; 2 trials, n = 621), and oral sulfate solution (OSS; 3 trials, n = 597) was adequate in 75.2%, 82.9%, 81.9%, and 92.1%, respectively, of patients; however, heterogeneity between studies was considerable (I² range: 86-98%). Pooled ADRs were 31.1% with SPMC, 32.3% with 1L-PEGA, 30.4% with NaP, and 40.9% with OSS. Temporary electrolyte changes were seen with all ultra-low volume bowel preparation fluid solutions but without sustained effects in most patients.

CONCLUSION

Ultra-low volume bowel preparation fluids do not always meet the 90% quality standard for adequate bowel preparation as defined by current guidelines. Nonetheless, they may be considered in patients intolerant for higher-volume laxatives and without risk factors for inadequate bowel preparation or dehydration-related complications.

Sodium picosulfate/magnesium citrate versus 4L split-dose polyethylene glycol for bowel cleansing prior to colonoscopy in high fibre diet African patients

Introduction

an adequate bowel preparation is essential for good mucosal inspection during colonoscopy. This study aims to compare the efficacy of two validated oral lavage solutions for colonoscopy preparation in African patients.

Methods

a prospective observational study of patients undergoing colonoscopy in a referral endoscopy facility in Port Harcourt, Nigeria, using sodium picosulfate magnesium citrate (SPMC) and 4L split-dose polyethylene glycol (PEG). Variables collated were sociodemographic, primary indication, comorbidities, Aronchick bowel preparation scale, polyp/adenoma detection, caecal intubation and outcome. Statistical analysis was performed using IBM SPSS version 20.

Results

one hundred and twenty-four patients received PEG prior to colonoscopy and SPMC in 175 patients. The age range was from 22 to 92 years; mean age of 53.8 ± 14.2 years for PEG group and 55.3 ± 13.2 years for SPMC group (p=0.361). There were 215 males and 84 females. An excellent/good bowel preparation scale was recorded in 77 (62%) PEG group and 130 (74.3%) for SPMC group (p=0.592). PEG was predominantly used in the early years of endoscopists practice with the odds ratio (OR) of no polyp detection in the PEG vs SPMC groups as 1.64 (confidence interval CI 1.06-2.55) versus 0.76 (CI 0.62-0.92), respectively (p=0.016). For no adenoma detection, OR was 4.18 (CI 1.12-15.60) versus OR 0.63 (CI 0.52-0.75), respectively (p=0.012).

Conclusion

there is similar efficacy profile using either split volume PEG or SPMC prior to colonoscopy in these African patients. Polyp and adenoma detection rates are highly dependent on the expertise of the endoscopist.

Effect of bowel preparation volume in inpatient colonoscopy. Results of a prospective, randomized, comparative pilot study

Background

Inpatient status has been shown to be a predictor of poor bowel preparation for colonoscopy; however, the optimal bowel preparation regimen for hospitalized patients is unknown. Our aim was to compare the efficacy of bowel preparation volume size in hospitalized patients undergoing inpatient colonoscopy.

Methods

This prospective, single blinded (endoscopist), randomized controlled trial was conducted as a pilot study at a tertiary referral medical center. Hospitalized patients undergoing inpatient colonoscopy were assigned randomly to receive a high, medium, or low-volume preparation. Data collection included colon preparation quality, based on the Boston Bowel Preparation Scale, and a questionnaire given to all subjects evaluating the ability to completely finish bowel preparation and adverse effects (unpleasant taste, nausea, and vomiting).

Results

Twenty-five colonoscopies were performed in 25 subjects. Patients who received low-volume preparation averaged a higher mean total BBPS (7.4, SD 1.62), in comparison to patients who received high-volume (7.0, SD 1.41) and medium-volume prep (6.9, SD 1.55), P = 0.77. When evaluating taste a higher score meant worse taste. The low-volume group scored unpleasant taste as 0.6 (0.74), while the high-volume group gave unpleasant taste a score of 2.2 (0.97) and the medium-volume group gave a score of 2.1 (1.36), P < 0.01.

Conclusion

In this pilot study we found that low-volume colon preparation may be preferred in the inpatient setting due its better rate of tolerability and comparable bowel cleanliness when compared to larger volume preparation, although we cannot overreach any definitive conclusion. Further more robust studies are required to confirm these findings.

Trial registration

The Affect of Low-Volume Bowel Preparation for Hospitalized Patients Colonoscopies. Trial registration: NCT01978509 (terminated). Retrospectively registered on November 07, 2013.

Sodium picosulphate or polyethylene glycol before elective colonoscopy in outpatients? A systematic review and meta-analysis

AIM

To determine the best option for bowel preparation [sodium picosulphate or polyethylene glycol (PEG)] for elective colonoscopy in adult outpatients.

METHODS

A systematic review of the literature following the PRISMA guidelines was performed using Medline, Scopus, EMBASE, Central, Cinahl and Lilacs. No restrictions were placed for country, year of publication or language. The last search in the literature was performed on November 20^th, 2017. Only randomized clinical trials with full texts published were included. The subjects included were adult outpatients who underwent bowel cleansing for elective colonoscopy. The included studies compared sodium picosulphate with magnesium citrate (SPMC) and PEG for bowel preparation. Exclusion criteria were the inclusion of inpatients or groups with specific conditions, failure to mention patient status (outpatient or inpatient) or dietary restrictions, and permission to have unrestricted diet on the day prior to the exam. Primary outcomes were bowel cleaning success and/or tolerability of colon preparation. Secondary outcomes were adverse events, polyp and adenoma detection rates. Data on intention-to-treat were extracted by two independent authors and risk of bias assessed through the Jadad scale. Funnel plots, Egger’s test, Higgins’ test (I²) and sensitivity analyses were used to assess reporting bias and heterogeneity. The meta-analysis was performed by computing risk difference (RD) using Mantel-Haenszel (MH) method with fixed-effects (FE) and random-effects (RE) models. Review Manager 5 (RevMan 5) version 6.1 (The Cochrane Collaboration) was the software chosen to perform the meta-analysis.

RESULTS

662 records were identified but only 16 trials with 6200 subjects were included for the meta-analysis. High heterogeneity among studies was found and sensitivity analysis was needed and performed to interpret data. In the pooled analysis, SPMC was better for bowel cleaning [MH FE, RD 0.03, IC (0.01, 0.05), P = 0.003, I² = 33%, NNT 34], for tolerability [MH RE, RD 0.08, IC (0.03, 0.13), P = 0.002, I² = 88%, NNT 13] and for adverse events [MH RE, RD 0.13, IC (0.05, 0.22), P = 0.002, I² = 88%, NNT 7]. There was no difference in regard to polyp and adenoma detection rates. Additional analyses were made by subgroups (type of regimen, volume of PEG solution and dietary recommendations). SPMC demonstrated better tolerability levels when compared to PEG in the following subgroups: “day-before preparation” [MH FE, RD 0.17, IC (0.13, 0.21), P < 0.0001, I² = 0%, NNT 6], “preparation in accordance with time interval for colonoscopy” [MH RE, RD 0.08, IC (0.01, 0.15), P = 0.02, I² = 54%, NNT 13], when compared to “high-volume PEG solutions” [MH RE, RD 0.08, IC (0.01, 0.14), I² = 89%, P = 0.02, NNT 13] and in the subgroup “liquid diet on day before” [MH RE, RD 0.14, IC (0.06,0.22), P = 0.0006, I² = 81%, NNT 8]. SPMC was also found to cause fewer adverse events than PEG in the “high-volume PEG solutions” [MH RE, RD -0.18, IC (-0.30, -0.07), P = 0.002, I² = 79%, NNT 6] and PEG in the “low-residue diet” subgroup [MH RE, RD -0.17, IC (-0.27, 0.07), P = 0.0008, I² = 86%, NNT 6].

CONCLUSION

SPMC seems to be better than PEG for bowel preparation, with a similar bowel cleaning success rate, better tolerability and lower prevalence of adverse events.