Irritable Bowel Syndrome Characterized by ConstipationNCT03687814
Low FODMAP Plus PEG 3350 for the Treatment of Patients with Irritable Bowel Syndrome-Constipation
A study testing Low FODMAP diet/PEG 3350 in people with Irritable Bowel Syndrome Characterized by Constipation, run by University of Michigan at 1 site in United States.
Trial summary
Consecutive patients with Irritable Bowel Syndrome with Constipation (IBS-C) will be recruited from the outpatient clinics of the University of Michigan Health System. Eligible patients will be asked to participate in a study that will test the efficacy the PEG 3350 + a diet low in fermentable oligo, di… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Irritable Bowel Syndrome Characterized by Constipation
- What is being tested?
- Low FODMAP diet/PEG 3350
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 78 participants
- Where
- 1 siteUnited States
- Study dates
- 8 Nov 2018to Jan 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 1. Subjects aged 18 and older meeting the Rome IV criteria for IBS-C:
- Recurrent abdominal pain, on average, at least 1 day/week in the last 3 months, associated with two or more of the following:
- related to defecation
- associated with a change in the frequency of stool (reduction of stools)
- associated with a change in the form of stool (hard or lumpy stools) AND >25% hard stools and <25% loose stools * Criteria fulfilled for the last 3 months
Who cannot join
- any other IBS subtype other than IBS-C
- >3 spontaneous bowel movements during the last 7 days of run-in
- Have cognitive dysfunction or unable to understand or provide written informed consent
- Pregnancy (evaluated by self-report)
- Comorbid medical problems that may affect gastrointestinal transit or motility:
- Inflammatory bowel disease
Show all 13Show fewer
- Extra-intestinal disease known to affect the gastrointestinal system (i.e., scleroderma, unstable thyroid disease, etc.)
- Severe renal or hepatic disease
- Previous abdominal surgery other than appendectomy, cholecystectomy, and gynecologic/urologic surgery if performed more than six months prior to enrollment
- Previous treatment with the low FODMAP diet under a dietician guidance
- Concurrent medications not permitted including probiotics, antibiotics, prescription or over-the-counter medication for IBS, and narcotics
- New antidepressant use (less than 3 months on stable dose)
- Active participation in another form of dietary therapy
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Michigan
Ann Arbor, Michigan, 48109
Stacy Menees, MD
About this study
Consecutive patients with Irritable Bowel Syndrome with Constipation (IBS-C) will be recruited from the outpatient clinics of the University of Michigan Health System. Eligible patients will be asked to participate in a study that will test the efficacy the PEG 3350 + a diet low in fermentable oligo, di, monosaccharides, and polyols (FODMAP) vs. PEG 3350 plus sham diet. Blinding dietary advice trials is challenging and therefore the sham diet was based on the criteria set forth by Staudacher et al. which emphasizes that the diet must give the impression that is the true intervention diet with similar restrictions, modifications, and time intensity without impacting the intake of essential nutrients, fiber, and FODMAPs. An example of the sham diet's carbohydrates includes: apples, bananas, and pears, and wheat. Oranges, raspberries, strawberries and rice would not be allowed. Additionally, the physicians analyzing the data will be blinded as to which group the patients were randomized.
Read the detailed description
- Specific Aims: While a diet low in fermentable oligo, di, monosaccharides and polyols (FODMAPs) has gained popularity as a treatment for patients with Irritable Bowel Syndrome and diarrhea (IBS-D), the impact of this diet on patients with IBS and constipation (IBS-C) is unknown. We propose a randomized, controlled trial in IBS-C patients to compare the efficacy of PEG 3350 and the low FODMAP diet to PEG 3350 and a sham diet. We hypothesize that:
- The PEG 3350 and low FODMAP diet group will achieve greater improvements in abdominal symptoms including pain, discomfort, and bloating than the group receiving PEG 3350 and the sham diet.
- The PEG 3350 and low FODMAP diet group will achieve greater improvements in IBS related quality of life and anxiety than the group receiving PEG 3350 and the sham diet.
- Both strategies will improve constipation related complaints including stool frequency, stool consistency and straining to a similar degree.
We plan to test our central hypothesis and, thereby, accomplish the objective of this application by pursuing the following 2 specific aims:
Aim 1: Compare the proportion of patients with IBS-C on a diet of low FODMAP diet plus PEG 3350 vs. sham diet plus PEG 3350 reporting an improvement of abdominal pain. Our working hypothesis is that a higher proportion of patients randomized to the low FODMAP diet plus PEG 3350 will experience a reduction in the abdominal pain when compared to PEG 3350 plus sham diet alone.
Aim 2: Compare the efficacy of the low FODMAP diet plus PEG 3350 vs. sham diet plus PEG 3350 on pre-specified key clinical and disease specific quality of life endpoints in patients with IBS-C. Through our randomized controlled trial, we will assess the impact of the dietary interventions on stool consistency, stool frequency, and bloating and quality of life endpoints.
A positive result to this study would have significant impact on the treatment of patients with IBS by expanding the indications for the low FODMAP diet to all affected patients, regardless of bowel subtype. This would be particularly relevant to IBS-C patients for whom we currently have few evidence-based diet recommendations outside of increasing fiber intake.
- Being tested
- Low FODMAP diet/PEG 3350, sham diet/PEG 3350
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low FODMAP diet/PEG 3350Other
Also called low FODMAP diet
Subjects will follow a low FODMAP diet and will take PEG 3350 (Miralax) at 17.7 g (single dose) daily for 4 weeks.
sham diet/PEG 3350Other
Also called sham diet
Subjects will follow a sham diet and will take PEG 3350 (Miralax) at 17.7 g (single dose) daily for 4 weeks.
| Study group | Role | What they receive |
|---|---|---|
| Low FODMAP diet plus PEG 3350 | Experimental | Subjects will follow a low FODMAP diet and will take PEG 3350 (Miralax). Receives: Other: Low FODMAP diet/PEG 3350 |
| Sham diet plus PEG 3350 | Sham comparator | Subjects will follow a sham diet and will take PEG 3350 (Miralax). Receives: Other: sham diet/PEG 3350 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Improvement of abdominal pain as measured by 11-point numerical rating scale
Compare the proportion of patients with IBS-C on a diet of low FODMAP diet plus PEG 3350 vs. sham diet plus PEG 3350 reporting an improvement of abdominal pain. It is defined 30% reduction in abdominal pain during weeks 3 \& 4 of each diet compared with baseline using an 11-point numerical rating scale (NRS) (0-no pain, 11-intolerable pain). Appropriate between-group statistical comparisons will be conducted.
Measured: during weeks 3 and 4
Secondary outcomes (11)
Bloating
The change in mean score from baseline on the daily 11-point NRS averaged over each treatment week for bloating severity will be compared between the 2 groups.
Measured: each treatment week (4 weeks)
abdominal discomfort
30% reduction in abdominal discomfort during weeks 3 \& 4 of each diet compared with baseline using an 11-point NRS. Appropriate between-group statistical comparisons will be conducted.
Measured: during weeks 3 and 4
Mean number of SBMs per day
These will be measured in the last treatment week (the 7-day period before visit 4): The proportion of responders between the 2 groups will be compared. An SBM was defined as a bowel movement that occurred without the use of rescue medication or ≥24 h after the use of rescue medication.
Measured: week 4
Mean weekly number of spontaneous complete bowel movements
These will be tallied in the last treatment week (the 7-day period before visit 4):(SCBMs; derived from the number of SBMs without a feeling of incomplete evacuation)
Measured: last treatment week
Composite endpoint: Full responder was defined as a patient with >3 SBM per week, an increase of ≥1 SBM per week and >30% pain reduction.
during weeks 3 \& 4
Measured: during weeks 3 & 4
stool consistency
a responder will be defined as one who reports an increase in mean daily BSFS value of 1 or more compared to baseline for ≥2 of 4 treatment weeks. The proportion of responders between the 2 groups will be compared. Between group differences in the proportion of patients with an increase in BSFS value of ≥1
Measured: Over the 4 weeks of treatment
Straining
The change from baseline in daily numerical rating scale scored as 0 (none), 1 (slight), 2 (mild), 3 (moderate) and 4 (severe) scores averaged over each treatment week for straining will be compared between the 2 groups
Measured: 4 weeks
IBS-QOL
assess change in IBS-QOL from baseline and the last week of treatment week 4
Measured: baseline and week 4
HADS score
assess change in HADS score from baseline and the last week of treatment of week 4
Measured: baseline and week 4
WPAI questionnaire
assess change in WPAI questionnaire from baseline and the last week of treatment of week 4
Measured: baseline and week 4
Sleep Assessment questionnaire
assess change in Sleep Assessment questionnaire from baseline and the last week of treatment of week 4
Measured: baseline and week 4
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Sep 2018
- Study start8 Nov 2018
- Primary completionJan 2026 (estimated)
- Study completionJan 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Irritable Bowel Syndrome Characterized by ConstipationStudies of the same condition, open and under way.
- More trials run by University of MichiganThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 78 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Michigan
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Stacy Menees, University of Michigan
- Investigators
- Stacy B Menees, MD, MS, Principal investigator, University of Michigan
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03687814
- Sponsor's protocol ID
- HUM00139784
- Status last verified
- Feb 2025
- First submitted
- 25 Sep 2018
- Last updated
- 4 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Low FODMAP Plus PEG 3350 for the Treatment of Patients with Irritable Bowel Syndrome-Constipation
- ClinicalTrials.gov ID
- NCT03687814
- Acronym / sponsor ID
- HUM00139784
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 78 participants (estimated)
- Lead sponsor
- University of MichiganUniversity, hospital or other
- Study start
- 8 Nov 2018 (actual)
- Primary completion
- Jan 2026 (estimated)
- Study completion
- Jan 2026 (estimated)
- First posted
- 27 Sep 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Consecutive patients with Irritable Bowel Syndrome with Constipation (IBS-C) will be recruited from the outpatient clinics of the University of Michigan Health System. Eligible patients will be asked to participate in a study that will test the efficacy the PEG 3350 + a diet low in fermentable oligo, di, monosaccharides, and polyols (FODMAP) vs. PEG 3350 plus sham diet. Blinding dietary advice trials is challenging and therefore the sham diet was based on the criteria set forth by Staudacher et al. which emphasizes that the diet must give the impression that is the true intervention diet with similar restrictions, modifications, and time intensity without impacting the intake of essential nutrients, fiber, and FODMAPs. An example of the sham diet's carbohydrates includes: apples, bananas, and pears, and wheat. Oranges, raspberries, strawberries and rice would not be allowed. Additionally, the physicians analyzing the data will be blinded as to which group the patients were randomized.
Detailed description
- Specific Aims: While a diet low in fermentable oligo, di, monosaccharides and polyols (FODMAPs) has gained popularity as a treatment for patients with Irritable Bowel Syndrome and diarrhea (IBS-D), the impact of this diet on patients with IBS and constipation (IBS-C) is unknown. We propose a randomized, controlled trial in IBS-C patients to compare the efficacy of PEG 3350 and the low FODMAP diet to PEG 3350 and a sham diet. We hypothesize that:
- The PEG 3350 and low FODMAP diet group will achieve greater improvements in abdominal symptoms including pain, discomfort, and bloating than the group receiving PEG 3350 and the sham diet.
- The PEG 3350 and low FODMAP diet group will achieve greater improvements in IBS related quality of life and anxiety than the group receiving PEG 3350 and the sham diet.
- Both strategies will improve constipation related complaints including stool frequency, stool consistency and straining to a similar degree.
We plan to test our central hypothesis and, thereby, accomplish the objective of this application by pursuing the following 2 specific aims:
Aim 1: Compare the proportion of patients with IBS-C on a diet of low FODMAP diet plus PEG 3350 vs. sham diet plus PEG 3350 reporting an improvement of abdominal pain. Our working hypothesis is that a higher proportion of patients randomized to the low FODMAP diet plus PEG 3350 will experience a reduction in the abdominal pain when compared to PEG 3350 plus sham diet alone.
Aim 2: Compare the efficacy of the low FODMAP diet plus PEG 3350 vs. sham diet plus PEG 3350 on pre-specified key clinical and disease specific quality of life endpoints in patients with IBS-C. Through our randomized controlled trial, we will assess the impact of the dietary interventions on stool consistency, stool frequency, and bloating and quality of life endpoints.
A positive result to this study would have significant impact on the treatment of patients with IBS by expanding the indications for the low FODMAP diet to all affected patients, regardless of bowel subtype. This would be particularly relevant to IBS-C patients for whom we currently have few evidence-based diet recommendations outside of increasing fiber intake.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Low FODMAP diet plus PEG 3350 | Experimental | Other: Low FODMAP diet/PEG 3350Subjects will follow a low FODMAP diet and will take PEG 3350 (Miralax). |
| Sham diet plus PEG 3350 | Sham comparator | Other: sham diet/PEG 3350Subjects will follow a sham diet and will take PEG 3350 (Miralax). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Recurrent abdominal pain, on average, at least 1 day/week in the last 3 months, associated with two or more of the following:
- related to defecation
- associated with a change in the frequency of stool (reduction of stools)
- associated with a change in the form of stool (hard or lumpy stools) AND >25% hard stools and <25% loose stools * Criteria fulfilled for the last 3 months
Key exclusion criteria (13 listed)
- any other IBS subtype other than IBS-C
- >3 spontaneous bowel movements during the last 7 days of run-in
- Have cognitive dysfunction or unable to understand or provide written informed consent
- Pregnancy (evaluated by self-report)
- Comorbid medical problems that may affect gastrointestinal transit or motility:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Low FODMAP diet/PEG 3350Also: low FODMAP dietSubjects will follow a low FODMAP diet and will take PEG 3350 (Miralax) at 17.7 g (single dose) daily for 4 weeks. | Other | Low FODMAP diet plus PEG 3350 |
| sham diet/PEG 3350Also: sham dietSubjects will follow a sham diet and will take PEG 3350 (Miralax) at 17.7 g (single dose) daily for 4 weeks. | Other | Sham diet plus PEG 3350 |
Primary outcome
Improvement of abdominal pain as measured by 11-point numerical rating scale
Time frame: during weeks 3 and 4
Compare the proportion of patients with IBS-C on a diet of low FODMAP diet plus PEG 3350 vs. sham diet plus PEG 3350 reporting an improvement of abdominal pain. It is defined 30% reduction in abdominal pain during weeks 3 \& 4 of each diet compared with baseline using an 11-point numerical rating scale (NRS) (0-no pain, 11-intolerable pain). Appropriate between-group statistical comparisons will be conducted.
11 secondary outcomes
Bloating
Time frame: each treatment week (4 weeks)
abdominal discomfort
Time frame: during weeks 3 and 4
Mean number of SBMs per day
Time frame: week 4
Mean weekly number of spontaneous complete bowel movements
Time frame: last treatment week
Composite endpoint: Full responder was defined as a patient with >3 SBM per week, an increase of ≥1 SBM per week and >30% pain reduction.
Time frame: during weeks 3 & 4
stool consistency
Time frame: Over the 4 weeks of treatment
Straining
Time frame: 4 weeks
IBS-QOL
Time frame: baseline and week 4
HADS score
Time frame: baseline and week 4
WPAI questionnaire
Time frame: baseline and week 4
Sleep Assessment questionnaire
Time frame: baseline and week 4
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Mar 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Stacy B Menees, MD, MS principal investigator
University of Michigan
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Low FODMAP diet/PEG 3350 in people with Irritable Bowel Syndrome Characterized by Constipation, run by University of Michigan at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 4 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Stacy Menees, MD, MS (734-232-3739, sbartnik@med.umich.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Improvement of abdominal pain as measured by 11-point numerical rating scale (time frame: during weeks 3 and 4). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Mar 2025.