Combination could be another tool for bowel preparation?

Linaclotide combined with polyethylene glycol regimen for bowel preparation in patients with chronic constipation: A prospective randomized controlled study

BACKGROUND

The standard of bowel preparation sometimes is not met by using the 3 L polyethylene glycol electrolyte (PEG) method in patients with chronic constipation, which significantly impacts the diagnosis of colorectal diseases. Linaclotide can be utilized for the treatment of chronic idiopathic constipation. It is worth investigating whether linaclotide combined with 3 L PEG regimen can further optimize intestinal preparation in patients with chronic constipation.

AIM

To evaluate the efficacy and comfort of linaclotide combined with PEG for bowel preparation in patients with chronic constipation by comparing with PEG.

METHODS

From July 2021 to December 2022, 120 patients with chronic constipation who underwent colonoscopy at the Department of Gastroenterology, the Second Affiliated Hospital of Wenzhou Medical University were selected as research subjects. Using the random number table method, the patients were randomly divided into either a control group or an observation group. Both groups were given 3 L PEG and methylene silicone oil, and the observation group was additionally given three linaclotide capsules. The score of Boston Bowel Preparation Scale (BBPS), colonoscopy entry time, the detection rate of polyps or adenomas, and the incidence of adverse reactions were compared between two groups. Independent sample t test and χ² test were used for statistical comparisons.

RESULTS

The BBPS scores of the right segment, the middle segment, and the left segment, as well as the BBPS score of the overall bowel were higher in the observation group (P < 0.05). The colonoscopy entry time was shorter in the observation group (P < 0.05). The detection rates of polyps and adenomas (22% [11/50] vs 46% [23/50]; 14% [7/50] vs 32% [16/50]) differed significantly between the control group and observation group (P < 0.05). The incidence of adverse reactions in the observation group was significantly shorter than that of the control group (P < 0.05).

CONCLUSION

Compared with the 3 L PEG method, linaclotide combined with 3 L PEG regimen can achieve better bowel preparation effect, reduce the incidence of adverse reactions, and has higher safety, which is worthy of further clinical promotion.

Low-volume regimen without additional liquids or adjunctive agents versus standard bowel preparation in non-constipated patients: a propensity score matching analysis

AIMS

Split-dose, 4-L polyethylene glycol (PEG, HSD) is currently the first-line choice for unselected or difficult colon preparations. Almost all low-volume bowel preparations (BPs) include a large volume of additional liquid and adjunctive agents to improve cleansing efficiency. However, neither HSD nor additional liquids or adjunctive agents of low-volume regimens may be necessary for low-risk patients. The aim of this study was to compare the cleansing efficiency between split-dose, low-volume (2-L) PEG without additional liquids or adjunctive agents (LSD) and HSD in non-constipated patients.

METHODS

A retrospective study was performed from January 2013 to December 2015. Consecutive non-constipated patients who received LSD or HSD BPs were enrolled into LSD and HSD groups. Propensity score matching (PSM) was used to reduce selection bias and potential confounders. The primary outcome was bowel cleansing quality, as evaluated by the Boston Bowel Preparation Scale (BBPS). The adenoma detection rate (ADR), the most important secondary outcome, was also recorded. Follow-up was conducted in 2016.

RESULTS

After excluding those participants who meet exclusion criteria or lost follow-up, 1656 non-constipated patients underwent LSD (n = 999) or HSD (n = 657) BP. Most patients had a BBPS score ≥6 (LSD vs. HSD, 93.6 vs. 92.9%, p = .166). The segmental BBPS scores were ≥2 in 92 and 91.9% in the LSD and HSD groups, respectively. The overall ADR was 16.7% in the LSD group and 17.5% in the HSD group (p = .334).

CONCLUSION

For non-constipated patients, LSD is not inferior to HSD in cleansing efficiency, while more willing to repeat the same BP.

Comparison of 1L Adjuvant Auxiliary Preparations with 2L Solely Polyethylene Glycol plus Ascorbic Acid Regime for Bowel Cleaning: A Meta-analysis of Randomized, Controlled Trials

The effectiveness of additional usage of adjuvants for bowel preparation is still unclear. This study compared 1L polyethylene glycol plus ascorbic acid with adjuvant drug regimens (1L PEG-AA, lower volume) with 2L polyethylene glycol plus ascorbic acid (2L PEG-A, low volume) to evaluate whether the adjuvants can be used to reduce the standard dosage of purgative further. The PubMed/MEDLINE, EMBASE, Cochrane Library, and Web of Science database were searched for randomized controlled trials (RCTs). The primary outcome was the efficacy of bowel preparation, and the secondary outcomes were patients' tolerability and complication rate. The overall quality of evidence was assessed using the GRADEpro guideline development tool. Five RCTs with a total of 1013 patients from Korea were included. The majority of patients were outpatients from different hospitals. The pooled data showed no significant difference in the adequate bowel preparation rate (89.3% versus 89.4%, RR 1, 95% CI 0.95-1.05, I ² = 47%) as well as in the complication rate (RR for nausea 1.22, 95% CI 0.89-1.65, I ² = 49%; RR for bloating 0.96, 95% CI 0.73-1.28, I ² = 0%; RR for vomiting 0.69, 95% CI 0.32-1.50, I ² = 33%; RR for abdominal pain 1.01, 95% CI 0.61-1.69, I ² = 0%). But a significantly higher willingness rate was observed in the lower volume (85.1% versus 67.9%, RR 1.25, 95% CI 1.14-1.38, I ² = 46%). The quality of primary outcome evidence was moderate. The findings of this meta-analysis revealed that 1L PEG-AA may be a viable alternative to 2L PEG-A, with comparable effectiveness, better patient preference, and no statistically significant adverse event occurrence.

The advantage of polyethylene glycol electrolyte solution combined with lactulose in patients with long interval preparation-to-colonoscopy

BACKGROUND/AIMS

The main aim of the present study was to assess the efficacy of polyethylene glycol electrolyte (PEG) solution combined with lactulose in bowel preparation to find a new method for colonoscopy preparation to improve the quality of colonoscopy in patients with long interval preparation-to-colonoscopy (P-C).

MATERIALS AND METHODS

A prospective, randomized, endoscopist-blinded and placebo-controlled study was conducted. Three hundred sixty patients who were scheduled for colonoscopy were enrolled in the study. They were randomly divided into the PEG-lactulose group and the PEG-placebo group with 180 patients per arm. Two of the most common methods for estimating the quality of bowel preparation were the use of the Boston Bowel Preparation Scale and the measurement of the Bubble Scale and adenoma detection rate (ADR) as a secondary outcome of observation.

RESULTS

The PEG-lactulose group had a significant improvement in the quality of bowel preparation compared with the PEG-placebo group including colon cleanliness in interval P-C at 8 and 9 h (p<0.05) and bubble elimination in interval P-C at 5, 6, 7, 8, and 9 h (p<0.05). Compared with the PEG-placebo group, the ADR (23.3% vs. 15.0%, p<0.05) and the size (≤5 mm) of the adenoma (45.2% vs. 18.5%, p<0.05) increased in the PEG-lactulose group, and there were significant differences between the two groups.

CONCLUSION

PEG solution combined with lactulose can improve the quality of colonoscopy in patients with long interval P-C to allow the patients to select more flexible colonoscopy time. It is worth further popularizing in clinical practice.

Predictive factors for inadequate bowel preparation using low-volume polyethylene glycol (PEG) plus ascorbic acid for an outpatient colonoscopy

Low-volume polyethylene glycol (PEG) plus ascorbic acid solutions are widely used for bowel cleansing before colonoscopy. This study aimed to investigate the pre-endoscopic predictive factors for inadequate preparation in subjects receiving low-volume PEG plus ascorbic acid. A prospective study was performed at Gangnam Severance Hospital, Korea, from June 2016 to December 2016. All participants received low-volume PEG plus ascorbic acid solutions for outpatient colonoscopy. The split-dose bowel preparation was administered in subject with morning colonoscopy while same day bowel preparation was used for afternoon colonoscopy. 715 patients were enrolled (mean age 56.1 years, 54.4% male), of which 138 (19.3%) had an inadequate bowel preparation. In multivariable analysis, cirrhosis (OR 4.943, 95% CI 1.191–20.515), low (less than 70%) compliance for three-day low-residual diet (OR 2.165, 95% CI 1.333–3.515), brown liquid rectal effluent (compared with clear or semi-clear effluent) (OR 7.604, 95% CI, 1.760–32.857), and longer time interval (≥2 hours) between last defecation and colonoscopic examination (OR 1.841, 95% CI, 1.190–2.849) were found as an independent predictors for inadequate preparation. These predictive factors may be useful in guiding additional intervention to improve quality of bowel preparation.

Strategies to Improve Inadequate Bowel Preparation for Colonoscopy

Bowel cleansing is one of the most important parameters included in the evaluation of colonoscopy quality. The available evidence suggests that inadequate bowel preparation reduces the diagnostic yield of colorectal neoplasia and increases post-colonoscopy colorectal cancer risk. Nowadays, up to 30% of patients referred for colonoscopy have a poor bowel cleansing. Recently, several studies have analyzed the risk factors for inadequate bowel cleansing as well as the strategies to optimize bowel preparation. In this review, we have focused on summarizing the available evidence in this field.

Strategies to optimise the quality of bowel cleansing

Colonoscopy is the gold standard procedure for detecting neoplastic lesions of the colon and its efficiency is closely linked to the quality of the procedure. Adequate bowel preparation is a crucial factor in achieving the recommended quality indicators, but poor preparation has been reported in up to 30% of outpatients referred for colonoscopy. Consequently, over recent years, a number of studies have developed strategies to optimise bowel cleansing by improving adherence and tolerance to and the efficacy of the bowel preparation. Moreover, the identification of risk factors for inadequate bowel cleansing has led to tailored bowel preparation strategies being designed, with promising results. We aimed to review studies that assessed risk factors for inadequate bowel preparation and strategies to optimise bowel cleansing in patients at high risk of having poor preparation.

Impact of diet restriction on bowel preparation for colonoscopy

Diet restriction is one of the difficult parts of bowel preparation for colonoscopy, and many patients do not follow instructions properly. Few studies have evaluated the impact of dietary restriction in real clinical setting. The aim of this study was to study the effect of diet control on bowel preparation with detailed investigation of unacceptable food list in order to reveal what kind of foods are most problematic in clinical practice.Prospective observational study was carried out at a university-affiliated hospital. Around 4 L polyethylene glycol solution was used for bowel preparation on the day of colonoscopy. Patients were allowed to have regular diet until lunch the day before colonoscopy and educated to control diet from 3 days before colonoscopy with information regarding an unacceptable foods list. Factors associated with inadequate bowel preparation were analyzed using univariate statistics and multivariate logistic regression analysis.Of the 245 patients included in the study, 68 patients (27.8%) followed the diet instructions. Fiber-rich vegetables were the most commonly taken unacceptable foods (N = 143, 58.4%). Inadequate bowel preparation (fair and poor by Aronchick scale) was 47.3%. In multivariate analysis, diabetes [odds ratio (OR) 2.878, 95% confidence interval (CI) 1.242-6.671], preparation to colonoscopy interval (OR 1.003, 95% CI 1.000-1.005) and consumption of foods disturbing bowel preparation (OR 2.142, 95% CI 1.108-4.140) were independent predictors of inadequate bowel preparation.We could identify substantially low compliance to diet instructions in real clinical practice. Consumption of any foods disturbing bowel preparation was significant factor predicting inadequate bowel preparation, even though we could not select specific food list compromising preparation significantly. Favorable bowel preparation was achieved in the subgroup compliant to diet restriction, suggesting that regular diet avoiding specific kinds of foods can be possible option for diet restriction before colonoscopy.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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