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Comparative Effectiveness of Split-Dose Colonoscopy Bowel Preparation Regimens

Comparative Effectiveness of Split-Dose Colonoscopy Bowel Preparation Regimens

Status
Completed
Phases
Phase 4
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03298945
Enrollment
2239
Registered
2017-10-02
Start date
2018-12-13
Completion date
2024-06-30
Last updated
2025-02-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Colorectal Cancer

Keywords

colonoscopy, colorectal cancer, bowel preparation regimen, pragmatic trial

Brief summary

From the patients' perspective, the most formidable part of the colonoscopy experience is the process of bowel cleansing. A poorly tolerated bowel preparation regimen often leads to incompletion of scheduled colonoscopies which in turn undermines the effectiveness of colonoscopy, increases cost, and decreases patient satisfaction. The current standard bowel preparation in the VA is of larger volume and less palatable than another commonly used bowel preparation regimen. The investigators propose to compare these two commonly used bowel preparations with respect to the overall completion rate of scheduled colonoscopies in a real-world VA practice setting. The results of the study can be immediately applied to maximize the effectiveness of colonoscopy and increase patient satisfaction in the VA.

Detailed description

Anticipated Impacts on Veterans Health Care: by identifying a colonoscopy bowel preparation regimen which is the most effective in real-world VA practice and can be immediately implemented on a VA-wide scale, the proposed study will maximize the effectiveness of colonoscopy in reducing colorectal cancer (CRC) risk among Veterans, increase Veteran satisfaction, and reduce VA healthcare cost. Background: CRC is a leading cause of cancer-related death among Veterans. Colonoscopy can effectively reduce CRC incidence and mortality. However, non-adherence to screening colonoscopy substantially undermines this benefit. Existing evidence indicates that a disagreeable bowel preparation is a leading barrier to completing a colonoscopy from the patients' perspective. The taste and the volume of the bowel preparation determine patient tolerability and compliance to the preparation instructions, which in turn affects the incompletion (e.g., cancellation/no-show/reschedule) rate of scheduled colonoscopies as well as the effectiveness of the completed colonoscopies and patient satisfaction. The two most commonly used preparations currently in the US are the split-dose 4L polyethylene glycol (PEG) and the split-dose 2L MiraLAX/Gatorade preparations. While a high-volume regimen may in theory be more effective than a lower volume one, it may be associated with lower tolerability and adherence in real-world practice. Three small trials have compared these two preparations. However, data from these explanatory trials cannot inform policy decisions because they were conducted under artificial conditions, restricted among narrow patient populations, and most importantly not designed to capture the full impact of bowel preparation on the completion rate or effectiveness of colonoscopy. To address this critical knowledge gap, the investigators are proposing a pragmatic trial to determine the optimal split-dose bowel preparation in the general Veteran population. Objectives: to compare the real-world effectiveness of the two most commonly used split-dose colonoscopy bowel preparation regimens in the US (i.e., 4L PEG and 2L MiraLAX/Gatorade) with respect to the completion rate of scheduled colonoscopies, adenoma detection rate and secondarily preparation quality, cancellation/no-show rate and patient-oriented outcomes (e.g., willingness to repeat the preparation).

Interventions

DRUGMiralax-Gatorade Prep

2-L split-dose Miralax-Gatorade bowel prep for colonoscopy

4-L split dose Golytely is the current standard prep at the VA

Sponsors

VA Office of Research and Development
Lead SponsorFED

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
HEALTH_SERVICES_RESEARCH
Masking
SINGLE (Outcomes Assessor)

Intervention model description

Parallel groups

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* \> 18 years of age, and * being scheduled for outpatient elective screening, surveillance or diagnostic colonoscopies, and * the provider ordering the colonoscopy giving permission to enroll the patient.

Exclusion criteria

* Patients who are \<18 years * undergoing inpatient colonoscopy * those with contra-indications to receiving the standard 4L PEG-ELS colonoscopy bowel preparation (e.g., allergy to PEG) will be excluded * Those with a preference for a specific bowel preparation will be excluded. * The investigators are excluding inpatient colonoscopies because they account for a very small fraction of the total colonoscopies performed. * Also, inpatient colonoscopies are often performed for urgent reasons such that rapid bowel preparation procedures are followed. * In addition, because the objective of inpatient colonoscopy is often not to look for small polyps, the threshold for adequate bowel preparation quality might be different from that for outpatient procedures. * In addition, for patients undergoing more than 1 colonoscopy during the study period, only their first colonoscopy will be included in the primary analysis. * Patients who are undergoing a repeat colonoscopy for to a recent inadequate colonoscopy examination with poor bowel preparation will be excluded.

Design outcomes

Primary

MeasureTime frameDescription
Colonoscopy Completion RateThis outcome is determined within 1 month after colonoscopyThe completion rate of scheduled colonoscopy will be defined as the proportion of patients who show up for their scheduled colonoscopy and have endoscopist-rated adequate bowel preparation quality, among those scheduled for a colonoscopy.
Population Level Adenoma Detection Rate (ADR)within 1 month of colonoscopythe ADR is estimated as the proportion of patients with at least one adenoma detected among all patients scheduled for colonoscopy.

Secondary

MeasureTime frameDescription
Cancellation or No-show in Each Bowel Prep Armwithin 1 month after colonoscopyThe proportion of patients who cancel or no-show in each group.
Adequate Bowel Prep Qualitywithin 1 month after the colonoscopythis is a binary indictor based on endoscopist rating of excellent or good quality bowel preparation

Other

MeasureTime frameDescription
Hyponatremiawithin 6 months after colonoscopyHyponatremia
Renal Failurewithin 6 months of colonoscopyrenal failure documented in CPRS
Patients With Inadequate Bowel Preparation Who Are Recommended to Have Earlier-than-usual Follow-up Colonoscopywithin 1 month after colonoscopypatients with inadequate bowel preparation who are recommended to have earlier-than-usual follow-up colonoscopy

Countries

United States

Participant flow

Recruitment details

Participants were recruited based on referral from the primary care providers ordering colonoscopy at the Corporal Michael J. Crescenz Department of Veterans Affairs Medical Center. The first participant was enrolled on December 13, 2018, and the last participant was enrolled on January 27, 2023.

Pre-assignment details

Of the 3869 patients assessed for eligibility, 2239 met the eligibility criteria and were randomized.

Participants by arm

ArmCount
Golytely
4-L split-dose Golytely bowel prep Golytely: 4-L split dose Golytely is the current standard prep at the VA
1,139
Miralax-Gatorade Prep
2-L split-dose Miralax-Gatorade bowel prep Miralax-Gatorade Prep: 2-L split-dose Miralax-Gatorade bowel prep for colonoscopy
1,100
Total2,239

Baseline characteristics

CharacteristicMiralax-Gatorade PrepTotalGolytely
Age, Continuous62.6 years
STANDARD_DEVIATION 9.5
62.6 years
STANDARD_DEVIATION 7.2
62.6 years
STANDARD_DEVIATION 9.7
Alcohol use disorder116 Participants224 Participants108 Participants
Body mass index group
<18.5 kg/m^2
9 Participants19 Participants10 Participants
Body mass index group
18.5 to 24.9 kg/m^2
175 Participants373 Participants198 Participants
Body mass index group
25 to 29.9 kg/m^2
368 Participants763 Participants395 Participants
Body mass index group
30 or more kg/m^2
543 Participants1070 Participants527 Participants
Body mass index group
Missing
5 Participants14 Participants9 Participants
Colonoscopy indications
Diagnostic
152 Participants323 Participants171 Participants
Colonoscopy indications
Screening
508 Participants989 Participants481 Participants
Colonoscopy indications
Surveillance
440 Participants927 Participants487 Participants
Constipation or narcotic use22 Participants41 Participants19 Participants
Diabetes mellitus329 Participants663 Participants334 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
48 Participants84 Participants36 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
1020 Participants2094 Participants1074 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
32 Participants61 Participants29 Participants
Mental health disorders398 Participants769 Participants371 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Asian
18 Participants28 Participants10 Participants
Race (NIH/OMB)
Black or African American
397 Participants804 Participants407 Participants
Race (NIH/OMB)
More than one race
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
18 Participants27 Participants9 Participants
Race (NIH/OMB)
Unknown or Not Reported
36 Participants79 Participants43 Participants
Race (NIH/OMB)
White
631 Participants1301 Participants670 Participants
Sex: Female, Male
Female
113 Participants220 Participants107 Participants
Sex: Female, Male
Male
987 Participants2019 Participants1032 Participants
Smoking status
Current smoker
306 Participants633 Participants327 Participants
Smoking status
Former smoker
430 Participants885 Participants455 Participants
Smoking status
Missing
25 Participants35 Participants10 Participants
Smoking status
Never smoker
339 Participants686 Participants347 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
7 / 1,1394 / 1,100
other
Total, other adverse events
0 / 1,1390 / 1,100
serious
Total, serious adverse events
6 / 1,1395 / 1,100

Outcome results

Primary

Colonoscopy Completion Rate

The completion rate of scheduled colonoscopy will be defined as the proportion of patients who show up for their scheduled colonoscopy and have endoscopist-rated adequate bowel preparation quality, among those scheduled for a colonoscopy.

Time frame: This outcome is determined within 1 month after colonoscopy

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
GolytelyColonoscopy Completion Rate591 Participants
Miralax-Gatorade PrepColonoscopy Completion Rate600 Participants
Primary

Population Level Adenoma Detection Rate (ADR)

the ADR is estimated as the proportion of patients with at least one adenoma detected among all patients scheduled for colonoscopy.

Time frame: within 1 month of colonoscopy

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
GolytelyPopulation Level Adenoma Detection Rate (ADR)383 Participants
Miralax-Gatorade PrepPopulation Level Adenoma Detection Rate (ADR)364 Participants
Secondary

Adequate Bowel Prep Quality

this is a binary indictor based on endoscopist rating of excellent or good quality bowel preparation

Time frame: within 1 month after the colonoscopy

Secondary

Cancellation or No-show in Each Bowel Prep Arm

The proportion of patients who cancel or no-show in each group.

Time frame: within 1 month after colonoscopy

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
GolytelyCancellation or No-show in Each Bowel Prep Arm358 Participants
Miralax-Gatorade PrepCancellation or No-show in Each Bowel Prep Arm330 Participants
Other Pre-specified

Hyponatremia

Hyponatremia

Time frame: within 6 months after colonoscopy

Other Pre-specified

Patients With Inadequate Bowel Preparation Who Are Recommended to Have Earlier-than-usual Follow-up Colonoscopy

patients with inadequate bowel preparation who are recommended to have earlier-than-usual follow-up colonoscopy

Time frame: within 1 month after colonoscopy

Other Pre-specified

Renal Failure

renal failure documented in CPRS

Time frame: within 6 months of colonoscopy

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026