Trial Outcomes & Findings for The Role of Fiber in the Prevention and Treatment of Fecal Incontinence (NCT NCT04806386)

NCT ID: NCT04806386

Last Updated: 2026-06-30

Results Overview

The Shannon Diversity Index is a measure of within-sample microbial diversity that incorporates both the number of microbial taxa present (i.e., richness) and the distribution of their relative abundances (i.e., evenness). It is calculated using the relative abundance of observed taxa within each stool sample. Higher values indicate greater microbial diversity. The theoretical minimum value is 0, and there is no fixed theoretical maximum because the upper bound depends on the number of taxa detected in a sample and sequencing depth. In human gut microbiome studies, observed values commonly range from approximately 2 to 6.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

31 participants

Primary outcome timeframe

Change from baseline to final visit. Through study completion, up to 6 weeks.

Results posted on

2026-06-30

Participant Flow

Participant milestones

Participant milestones
Measure
Psyllium Fiber Supplement Treatment
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day.
Overall Study
STARTED
31
Overall Study
COMPLETED
30
Overall Study
NOT COMPLETED
1

Reasons for withdrawal

Reasons for withdrawal
Measure
Psyllium Fiber Supplement Treatment
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day.
Overall Study
Adverse Event
1

Baseline Characteristics

One participant did not complete the trial and therefore, their data was not analyzed.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Psyllium Fiber Supplement Treatment
n=31 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Age, Continuous
68.89 Years
STANDARD_DEVIATION 7.25 • n=20 Participants
Sex: Female, Male
Female
31 Participants
n=20 Participants • One participant did not complete the trial and therefore, their data was not analyzed.
Sex: Female, Male
Male
0 Participants
n=20 Participants • One participant did not complete the trial and therefore, their data was not analyzed.
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=20 Participants
Race (NIH/OMB)
Asian
0 Participants
n=20 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=20 Participants
Race (NIH/OMB)
Black or African American
0 Participants
n=20 Participants
Race (NIH/OMB)
White
30 Participants
n=20 Participants
Race (NIH/OMB)
More than one race
1 Participants
n=20 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
n=20 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants
n=20 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
30 Participants
n=20 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
n=20 Participants
Region of Enrollment
United States
31 Participants
n=20 Participants

PRIMARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

The Shannon Diversity Index is a measure of within-sample microbial diversity that incorporates both the number of microbial taxa present (i.e., richness) and the distribution of their relative abundances (i.e., evenness). It is calculated using the relative abundance of observed taxa within each stool sample. Higher values indicate greater microbial diversity. The theoretical minimum value is 0, and there is no fixed theoretical maximum because the upper bound depends on the number of taxa detected in a sample and sequencing depth. In human gut microbiome studies, observed values commonly range from approximately 2 to 6.

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Stool Metagenomics Assessed by Sequence-based Microbial Communities and Rare Taxa
-0.329 Shannon Diversity Index
Interval -0.479 to -0.178

PRIMARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

Butyrate was measured in stool samples using untargeted LC-MS metabolomics performed by Metabolon. Values were batch-normalized by dividing each sample value by the batch-specific median for butyrate, and missing values were imputed using the minimum observed value across batches. The resulting values were log-transformed before analysis. Higher values indicate greater relative abundance of butyrate in stool. Because this measure reflects relative abundance rather than absolute concentration, there is no fixed theoretical range.

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Stool Butyrate Abundance Measured by Untargeted LC-MS Metabolomics
0.629 log(ratio)
Interval 0.248 to 1.506

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

Questionnaire about the severity of symptoms in those with fecal incontinence. Consists of 4 questions, each rated on a scale of 1 to 6. Lower scores indicate higher severity of symptoms. (Min, 4, max 24)

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Fecal Incontinence Severity Assessed by Fecal Incontinence Severity Index (FISI)
-5 Score on a Scale
Interval -8.224 to -1.776

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

Questionnaire about the quality of life of those with fecal incontinence. Questions are rated from 1 to 4 in each of 4 sections. Lower rating represent worse quality of life and higher scores represent higher quality of life. (Min 4, max, 16)

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Fecal Incontinence Quality of Life Assessed by Fecal Incontinence Quality of Life (FIQL)
1.761 Score on Scale
Interval 0.88 to 2.641

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 participant did not complete the study due to side effects from fiber bar consumption.

Squeeze pressure assessed using a pressure sensory for Anorectal manometry (ARM) procedure performed to measure anal and rectal muscle function and sensation.

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Anal Squeeze Pressure Assessed by Anorectal Manometry
-6.872 mmHg
Interval -32.95 to 19.206

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

Translumbosacral anorectal magnetic stimulation (TAMS) performed during the ARM procedure to measure the change in the nerve conduction between the spinal cord and rectum.

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Lumbo and Sacral Nerve Latency Assessed by Translumbosacral Anorectal Magnetic Stimulation
-0.266 Milliseconds
Interval -0.794 to 0.262

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

A 7-point scale indicating overall fecal incontinence symptom relief where 1 represents completely relieved and 7 represents completely worse.

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Relief Assessed by the Global Assessment of Relief
-1.885 Score on scale
Interval -2.27 to -1.499

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

A 10-point scale indicating bloating severity where 0 represents the least severity and 10 represents the most severity.

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Bloating Scale Assessed by a Bloating Scale
0.885 Score on Scale
Interval -0.244 to 2.014

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

A 10-point scale indicating urgency severity where 0 represents the least severity and 10 represents the most severity

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Urgency Assessed by an Urgency Scale
-2.538 Score on a Scale
Interval -3.681 to -1.395

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

A 10-point scale indicating flatus severity where 0 represents the least severity and 10 represents the most severity

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Flatus Assessed by a Flatus Scale
-1.154 Score on a Scale
Interval -2.446 to 0.138

SECONDARY outcome

Timeframe: Change from baseline to final visit. Through study completion, up to 6 weeks.

Population: 1 Participant did not complete the study due to side effects from fiber bar consumption.

A measure of the subject's waist circumference in the area where the most bloating is experienced

Outcome measures

Outcome measures
Measure
Psyllium Fiber Supplement Treatment
n=30 Participants
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Change in Waist Circumference Measurement
-0.248 Centimeters (cm)
Interval -1.866 to 1.37

Adverse Events

Psyllium Fiber Supplement Treatment

Serious events: 1 serious events
Other events: 5 other events
Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure
Psyllium Fiber Supplement Treatment
n=31 participants at risk
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Nervous system disorders
Hospital Admission
3.2%
1/31 • Number of events 1 • 3 years

Other adverse events

Other adverse events
Measure
Psyllium Fiber Supplement Treatment
n=31 participants at risk
All patients will receive psyllium fiber in the form of edible bars, 7g, twice a day to total 14g per day. Psyllium: Psyllium fiber powder baked into a bar is commonly used as a first line of treatment for patients with fecal incontinence.
Gastrointestinal disorders
Abdominal Cramping, Increased Bowel Movements, Anal Pain
3.2%
1/31 • Number of events 2 • 3 years
Gastrointestinal disorders
Constipation, Bloating
3.2%
1/31 • Number of events 1 • 3 years
Gastrointestinal disorders
Constipation, Bloating, Distention, Increased Gas
3.2%
1/31 • Number of events 1 • 3 years
Gastrointestinal disorders
Increased Reflux, Bloating
3.2%
1/31 • Number of events 1 • 3 years
Gastrointestinal disorders
Bloating, Gas, Change in stool consistency
3.2%
1/31 • Number of events 1 • 3 years

Additional Information

Kyle Staller

Massachusetts General Hospital

Phone: 6177262000

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place