Effect of Low-volume (1L) vs Intermediate-volume (2L) Bowel Preparation on Cost-effectiveness and Quality of Life

Adequate bowel preparation for colonoscopy is paramount for optimal diagnostic accuracy and safety. However, the need for high volumes to clean the colon often makes it difficult for patients to adhere to. Therefore, new low volume bowel preparation fluids have been developed. Little is known on the impact of these low volume bowel preparation fluids (1L), compared to intermediate-volume (2L) laxatives on quality of life (QoL) and cost-effectiveness. This study aims to provide further evidence on the presumed positive effect of ultra-low volume bowel preparation on patients' QoL and cost-effectiveness, in addition to its already demonstrated positive effect on bowel cleansing for colonoscopy.

This multicenter randomized controlled trial (RCT) will be conducted in four hospitals in the Netherlands. Secure web-based questionnaires will be used before starting bowel preparation (baseline, t=0) and within 1 week (t=1) after colonoscopy, to assess the impact of bowel preparation on QoL and explore costs and productivity loss for cost-effectiveness analysis.

Background and aims: Adequate bowel preparation for colonoscopy is paramount for optimal diagnostic accuracy and safety. However, the need for high volumes to clean the colon often makes it difficult for patients to adhere to. Therefore, new low volume bowel preparation fluids have been developed. Little is known on the impact of these low volume bowel preparation fluids (1L), compared to intermediate-volume (2L) laxatives on quality of life (QoL) and cost-effectiveness. This study aims to provide further evidence on the presumed positive effect of ultra-low volume bowel preparation on patients' QoL and cost-effectiveness, in addition to its already demonstrated positive effect on bowel cleansing for colonoscopy.

Study design: This multicenter randomized controlled trial (RCT) will be conducted in four hospitals in the Netherlands. Secure web-based questionnaires will be used before starting bowel preparation (baseline, t=0) and within 1 week (t=1) after colonoscopy, to assess the impact of bowel preparation on QoL and explore costs and productivity loss for cost-effectiveness analysis. Data on colonoscopy findings and complications will be retrieved from the patients' medical record.

Study population: This multicenter study will include 470 patients from 4 hospitals.

Intervention: Patients will be randomized during the pre-colonoscopy hospital visit between a specialized low-volume 1-liter bowel preparation fluid (Pleinvue) or an intermediate-volume 2-liter bowel preparation fluid (Moviprep), which are already both routinely used as bowel preparation for colonoscopy in the Netherlands.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: There is no direct benefit for patients participating in this study. Risk associated with participation are considered minimal, and are limited to the possibility of privacy related issues. Nonetheless, this is considered to be minimal because of the use of pseudonymized data and GDPR compliant databases. In the future, results from this study could possibly benefit patients undergoing colonoscopy, with the possibility of reducing the need for repeat colonoscopies and improving patient experience of colonoscopies.

Eligibility Criteria:
Inclusion Criteria:

* Age \> 18 years
* Planned elective colonoscopy for surveillance or diagnostic indications

Exclusion Criteria:

* Therapeutic colonoscopy (e.g. endoscopic mucosal resection (EMR)
* History of (sub) total colectomy
* Inflammatory bowel disease (IBD)
* Inpatient status
* Indication for an intensified bowel preparation regime
* Emergency colonoscopy
* Limited Dutch language skills
* Dementia
* Visual impairment
* Commonly accepted contra-indications for non-iso osmotic bowel preparation and ascorbate:

  * Glucose-6-phosphate-dehydrogenase (G6PD) deficiency
  * (sub)ileus
  * Bowel obstruction or perforation
  * Acute abdomen
  * Gastroparesis
  * intolerance for any of the formulation ingredients
  * Severe renal insufficiency (creatinine clearance \< 30mL/min)
  * Congestive heart failure (NYHA III or IV)
  * Phenylketonuria