Efficacy And Tolerability Of Asymmetric Split Regimen For Bowel Preparation

Efficacy And Tolerability Of The Asymmetric Split Regimen With A Very Low Volume Bowel Preparation: Split-The-Split Study

The investigators aimed to compare the efficacy for bowel cleansing of a split-dose regimen with a low morning dose of PEG solution (Asymmetric; 25% of the dose is given on the day of the procedure and 75% of the dose is given on the day before) with the standard split-dose regimen in patients undergoing screening and surveillance colonoscopy using a very low volume bowel preparation (1L PEG+Ascorbate). Consecutive outpatients undergoing screening and surveillance colonoscopy were enrolled in a randomized, single-blind, non-inferiority clinical trial. Patients were randomly assigned to: group A, asymmetric split dose regimen (0,75 L of PEG + ASC the day before and 0,25 L 2:30 hours before colonoscopy); group B, symmetric split dose regimen (0,5 L of PEG + ASC the day before and 0,5 L 3 hours before colonoscopy). Primary endpoint was the proportion of adequate bowel cleansing. Moreover, all patients filled in a validated, nurse-administered questionnaire assessing compliance, tolerability and safety of bowel preparation.

Study Overview

• Status: Completed
• Conditions: Colon Preparation; Polyps Colorectal
• Intervention / Treatment: Drug: 1L PEG-Asc

Detailed Description

Prospective observational, single-blind study conducted in two endoscopy centers belonging to the same Local Health Authority. The two bowel preparation regimens under study (symmetric split and asymmetric split) will be compared in a population of patients undergoing screening for colorectal cancer.

Patient enrollment, product prescription, and the subsequent pre-endoscopic evaluation of safety, tolerability, acceptability, and compliance will be carried out by an assistant who will not be blinded to the type of preparation used.

Endoscopic evaluation, however, will be performed by an experienced endoscopist who will be blinded to the type of bowel preparation administered to the patient.

The bowel preparation product used consists of a very low-volume solution of Macrogol (3350) + Ascorbic Acid (1 liter) (PLENVU®, Norgine).

Bowel cleanliness level assessed using the Boston Bowel Preparation Scale adn overall tolerability of bowel preparation are primary outcomes.

Patient compliance and safety; the number of detected lesions, the percentage of complete colonoscopies, the duration of the colonoscopy, the degree of discomfort/pain perceived by the patient during the examination, and procedure-related complications are secondary outcomes.

Patients will be assigned to the two treatment groups according to a computer-generated sequence.

Data will be expressed as mean and standard deviation for quantitative variables and as frequencies for qualitative variables. The comparison between the two groups will be performed using the t-test for quantitative variables and the chi-square (χ²) test for qualitative variables.

• Study Type: Interventional
• Enrollment (Actual): 236
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Lombardia
    • Garbagnate Milanese, Lombardia, Italy, 20020
      • ASST Rhodense

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• All patients scheduled as outpatient for screening or surveillance colonoscopy

Exclusion Criteria:

• Inpatients
• refusal of split dose regimen for bowel preparation
• previous history of colorectal resection
• severe cardiac disease
• advanced (stage IV and V) chronic kidney disease
• pregnancy; ileus
• suspected bowel obstruction or toxic megacolon
• known inflammatory bowel disease
• known or suspected allergy to PEG.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Asymmetric split dose preparation; 75% of the dose is given on the day before of the procedure and 25% of the dose is given on the day of the procedure	Drug: 1L PEG-Asc; PEG 3350 plus sodium sulfate plus sodium chloride plus potassium chloride plus ascorbic acid plus sodium ascorbate
Active Comparator: Symmetric split dose preparation; 50% of the dose is given on the day before of the procedure and 50% of the dose is given on the day of the procedure	Drug: 1L PEG-Asc; PEG 3350 plus sodium sulfate plus sodium chloride plus potassium chloride plus ascorbic acid plus sodium ascorbate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quality of bowel prepreparation	Quality of bowel prepreparation/cleanliness scored using the Boston Bowel Preparation Scale. Each segment of the colon received a score from 0 to 3, and these segment scores were summed for a total BBPS score ranging from 0 to 9. The preparation was considered adequate when BBPS score was ≥ 6 with a score with at least 2 points in any segment	2 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adenoma detection rate	rate of patients with at least one adenoma	2 days
Rate of the occurrence of adverse events	Rate of the occurrence of adverse events (bad taste in mouth, gastric fullness, nausea or vomiting, bloating, abdominal pain, headache)	2 days
Compliance	Compliance was assessed by the amount of intake of study agents using a 3-point scale: 1 (100% intake), 2 (≥ 75% intake), and 3 (< 75% intake).	2 days
Tolerability of the preparation, as reported by the patient on a Validated Questionnaire	Tolerability was evaluated assessing how patient finds tolerable the bowel preparation by using a 4-point scale: 1 (Easy), 2 (Acceptable), 3 (Somewhat difficult), 4 (Very difficult), plus a Visual Scale with a number from 0 (untolerable) to 100 (very tolerable).	2 days

Collaborators and Investigators

• Sponsor: ASST Rhodense
• Investigators: Principal Investigator: Gianpiero Manes, ASST Rhodense

Study record dates

Study Major Dates

• Study Start (Actual): March 8, 2023
• Primary Completion (Actual): October 10, 2024
• Study Completion (Actual): October 10, 2024

Study Registration Dates

• First Submitted: April 1, 2025
• First Submitted That Met QC Criteria: April 1, 2025
• First Posted (Actual): April 8, 2025

Study Record Updates

• Last Update Posted (Actual): April 13, 2025
• Last Update Submitted That Met QC Criteria: April 10, 2025
• Last Verified: March 1, 2023

More Information

Terms related to this study

• Keywords: Bowel preparation; Colon cleansing; Asymmetric split regimen; Very low volume preparation; 1L PEG + ascorbate
• Other Study ID Numbers: 101-17022023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No