ConstipationNCT03842007
Understanding Mechanisms of Normal and Disordered Defecation
A study testing Rectal Barostat Study and Fecoflowmetry in people with Constipation, run by Mayo Clinic at 1 site in United States.
Trial summary
Researchers are trying to better understand why constipation occurs and improve the tests for diagnosing these conditions. Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Constipation
- What is being tested?
- Rectal Barostat Study and Fecoflowmetry
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 160 participants
- Where
- 1 siteUnited States
- Study dates
- 29 Jan 2019to Jun 2029
- 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 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Male and female volunteers aged 18-80 years.
- Able to provide written informed consent before participating in the study.
- Able to communicate adequately with the investigator and to comply with the requirements for the entire study.
- Individuals with chronic constipation for 1 year, with 2 or more of the following symptoms for 3 months or longer: <3 bowel motions/week, straining ≥ 25% of time, hard or lumpy stools ≥ 25% of time, anal digitation ≥ 25% of time, incomplete evacuation ≥ 25% of time, feeling of anorectal blockage ≥ 25% of time.
- Able to provide written informed consent before participating in the study.
- Able to communicate adequately with the investigator and to comply with the requirements for the entire study.
Who cannot join
- Clinical evidence of significant cardiovascular, respiratory, renal, hepatic, gastrointestinal, hematological, neurological, psychiatric or other disease that may interfere with the objectives of the study and/or pose safety concerns.
- Current symptoms of a functional gastrointestinal disorder assessed by questionnaire.
- Putative risk factors for pelvic floor trauma: i.e. six or more vaginal deliveries, birthweight >4500gms (macrosomia), or known 3rd or 4th degree perineal tear.
- Medications that are likely to alter gastrointestinal motility: e.g., opiates and anticholinergic medications; a stable dose of thyroxine and low doses of tricyclic agents (e.g., up to amitriptyline (50 mg daily).
- Active rectal inflammation, cancer; perianal sepsis; history of pelvic radiation, rectosigmoid surgery or inflammatory bowel disease.*
- Anxiety or depression as assessed by the Hospital Anxiety and Depression Questionnaire.
- Pregnant women, prisoners and institutionalized individuals.
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
Mayo Clinic in Rochester
Rochester, Minnesota, 55905
Kelly J Feuerhak, 507-255-6802, Feuerhak.Kelly@mayo.edu
Adil E Bharucha, MD
About this study
Researchers are trying to better understand why constipation occurs and improve the tests for diagnosing these conditions.
Read the detailed description
Study includes a screening visit and a study day. During the initial screening visit for this study, subjects will complete three (3) questionnaires about their bowel symptoms, overall health, and anxiety and depression. A blood sample (about 4 tablespoons) will be drawn to study the relationship between genes and certain bowel habits. Subjects will be asked to provide a single stool sample to look at the bacteria in the stool.
Before the study, subjects will receive 1 to 2 Fleet's enemas to clean the rectum. After receiving the Fleet's enema (administered through a small plastic tube in the rectum), a swab attached to a small rectal catheter will be used to brush the lining of the rectum and obtain a stool specimen. Then, rectal and anal pressures will be measured by placing a small catheter (plastic tube) in the rectum, and withdrawing it slowly. Rectal sensation will be measured by inflating a small balloon in the rectum.
There are 2 procedures (rectal barostat study and fecomanoflowmetry), each of which lasts approximately 90 minutes. During the rectal barostat study, contractions will be recorded with a balloon inserted into the rectum and inflated. After the barostat study is completed, your rectum will be filled with a small amount of paste. Two thin catheters will be inserted into the anus to measure pressures and electrical activity (electromyography or EMG). Then, you will be asked to sit on a commode, contract (squeeze) your anal muscles, blow into a balloon, and expel the paste into the commode.
- Conditions
- Constipation
- Being tested
- Rectal Barostat Study, Fecoflowmetry
- Medical subject headings
- Constipation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Rectal Barostat StudyDiagnostic test
Contractions will be recorded with a balloon inserted into the rectum and inflated
FecoflowmetryDiagnostic test
Rectum will be filled with a small amount of paste.Two thin catheters will be inserted into the anus to measure pressures and electrical activity (electromyography or EMG). Subjects will be asked to sit on a commode, contract (squeeze) your anal muscles, blow into a balloon, and expel the paste into the commode.
| Study group | Role | What they receive |
|---|---|---|
| Healthy Individuals | Active comparator | Sixty healthy individuals (20 men and 40 women) will undergo an anorectal study which comprises of a rectal barostat study followed by fecoflowmetry Receives: Diagnostic Test: Rectal Barostat Study; Diagnostic Test: Fecoflowmetry |
| Constipated Individuals | Active comparator | 60 constipated individuals (20 men and 40 women) will undergo an anorectal study which comprises of a rectal barostat study followed by fecoflowmetry Receives: Diagnostic Test: Rectal Barostat Study; Diagnostic Test: Fecoflowmetry |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rectal emptying
Measured by fecomanoflowmetry calculating the mean and maximum flow rate in various conditions (mg/sec), defecated volume (mg), flow time (sec) and time to maximum flow (sec). The amount of artificial stool evacuated is expressed in milligrams. The duration is in seconds. These 2 metrics are integrated to measure mg evacuated/second.
Measured: Baseline
Rectoanal pressures
Measured by anorectal manometry in mmHg
Measured: Baseline
Secondary outcomes (8)
Anal sphincter electromyography (EMG)
Units - mV
Measured: Baseline
Rectal compliance measured with a barostat
Pressure (mmHg) corresponding to half-maximum rectal volume during rectal distention
Measured: Baseline
Rectal Capacity measured with a barostat
Rectal volume (ml) at maximum distending pressure during rectal distention
Measured: Baseline
Rectal contractile response to distention measured with a sinusoidal oscillator
Rectal balloon is inflated to a preload volume of 125ml. The balloon is then oscillated around baseline volume by 25mL for 20 min at a frequency of 5 counts per minute (cpm). The mean rectal pressure (cm H2O) will be calculated over the multiple oscillation cycles within the 20 minute distention segment.
Measured: Baseline
Rectal sensory threshold for first sensation to defecate using barostat balloon distention
The sensory threshold for first sensation to defecate is measured by stepwise inflation of the balloon (0-44 mm Hg, at 4 mm Hg increments). During this assessment participants are asked to report when they have the first sensation to defecate.
Measured: Baseline
Rectal sensory threshold for desire to defecate using barostat balloon distention
The sensory threshold for desire to defecate is measured by stepwise inflation of the balloon (0-44 mm Hg, at 4 mm Hg increments). During this assessment participants are asked to report when they have the desire to defecate.
Measured: Baseline
Rectal sensory threshold for maximum urgency during barostat balloon distention
The sensory threshold for maximum urgency to defecate is measured by stepwise inflation of the balloon (0-44 mm Hg, at 4 mm Hg increments). During this assessment participants are asked to report when they have the maximum urgency to defecate.
Measured: Baseline
Rectal balloon expulsion time
During this test, the time (seconds) required to expel a water-filled rectal balloon (50 ml) will be compared between healthy people and patients
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Feb 2019
- Study start29 Jan 2019
- Primary completionDec 2028 (estimated)
- Study completionJun 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ConstipationStudies of the same condition, open and under way.
- More trials run by Mayo ClinicThe 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
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 160 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mayo Clinic
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Adil Bharucha, MBBS, MD, Mayo Clinic
- Investigators
- Adil E Bharucha, MD, Principal investigator, Mayo Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03842007
- Sponsor's protocol ID
- 18-010327
- Other IDs
- R01DK078924
- Status last verified
- Aug 2026
- First submitted
- 10 Jan 2019
- Last updated
- 21 Aug 2026
- 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 21 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Understanding Mechanisms of Normal and Disordered Defecation
- ClinicalTrials.gov ID
- NCT03842007
- Acronym / sponsor ID
- 18-010327
- Conditions
- Constipation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 160 participants (estimated)
- Lead sponsor
- Mayo ClinicUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 29 Jan 2019 (actual)
- Primary completion
- Dec 2028 (estimated)
- Study completion
- Jun 2029 (estimated)
- First posted
- 15 Feb 2019 (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.
Researchers are trying to better understand why constipation occurs and improve the tests for diagnosing these conditions.
Detailed description
Study includes a screening visit and a study day. During the initial screening visit for this study, subjects will complete three (3) questionnaires about their bowel symptoms, overall health, and anxiety and depression. A blood sample (about 4 tablespoons) will be drawn to study the relationship between genes and certain bowel habits. Subjects will be asked to provide a single stool sample to look at the bacteria in the stool.
Before the study, subjects will receive 1 to 2 Fleet's enemas to clean the rectum. After receiving the Fleet's enema (administered through a small plastic tube in the rectum), a swab attached to a small rectal catheter will be used to brush the lining of the rectum and obtain a stool specimen. Then, rectal and anal pressures will be measured by placing a small catheter (plastic tube) in the rectum, and withdrawing it slowly. Rectal sensation will be measured by inflating a small balloon in the rectum.
There are 2 procedures (rectal barostat study and fecomanoflowmetry), each of which lasts approximately 90 minutes. During the rectal barostat study, contractions will be recorded with a balloon inserted into the rectum and inflated. After the barostat study is completed, your rectum will be filled with a small amount of paste. Two thin catheters will be inserted into the anus to measure pressures and electrical activity (electromyography or EMG). Then, you will be asked to sit on a commode, contract (squeeze) your anal muscles, blow into a balloon, and expel the paste into the commode.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Healthy Individuals | Active comparator | Diagnostic Test: Rectal Barostat Study, Diagnostic Test: FecoflowmetrySixty healthy individuals (20 men and 40 women) will undergo an anorectal study which comprises of a rectal barostat study followed by fecoflowmetry |
| Constipated Individuals | Active comparator | Diagnostic Test: Rectal Barostat Study, Diagnostic Test: Fecoflowmetry60 constipated individuals (20 men and 40 women) will undergo an anorectal study which comprises of a rectal barostat study followed by fecoflowmetry |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Male and female volunteers aged 18-80 years.
- Able to provide written informed consent before participating in the study.
- Able to communicate adequately with the investigator and to comply with the requirements for the entire study.
- Individuals with chronic constipation for 1 year, with 2 or more of the following symptoms for 3 months or longer: <3 bowel motions/week, straining ≥ 25% of time, hard or lumpy stools ≥ 25% of time, anal digitation ≥ 25% of time, incomplete evacuation ≥ 25% of time, feeling of anorectal blockage ≥ 25% of time.
- Able to provide written informed consent before participating in the study.
Key exclusion criteria (7 listed)
- Clinical evidence of significant cardiovascular, respiratory, renal, hepatic, gastrointestinal, hematological, neurological, psychiatric or other disease that may interfere with the objectives of the study and/or pose safety concerns.
- Current symptoms of a functional gastrointestinal disorder assessed by questionnaire.
- Putative risk factors for pelvic floor trauma: i.e. six or more vaginal deliveries, birthweight >4500gms (macrosomia), or known 3rd or 4th degree perineal tear.
- Medications that are likely to alter gastrointestinal motility: e.g., opiates and anticholinergic medications; a stable dose of thyroxine and low doses of tricyclic agents (e.g., up to amitriptyline (50 mg daily).
- Active rectal inflammation, cancer; perianal sepsis; history of pelvic radiation, rectosigmoid surgery or inflammatory bowel disease.*
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 |
|---|---|---|
| Rectal Barostat StudyContractions will be recorded with a balloon inserted into the rectum and inflated | Diagnostic test | Constipated Individuals, Healthy Individuals |
| FecoflowmetryRectum will be filled with a small amount of paste.Two thin catheters will be inserted into the anus to measure pressures and electrical activity (electromyography or EMG). Subjects will be asked to sit on a commode, contract (squeeze) your anal muscles, blow into a balloon, and expel the paste into the commode. | Diagnostic test | Constipated Individuals, Healthy Individuals |
Primary outcome
Rectal emptying
Time frame: Baseline
Measured by fecomanoflowmetry calculating the mean and maximum flow rate in various conditions (mg/sec), defecated volume (mg), flow time (sec) and time to maximum flow (sec). The amount of artificial stool evacuated is expressed in milligrams. The duration is in seconds. These 2 metrics are integrated to measure mg evacuated/second.
Rectoanal pressures
Time frame: Baseline
Measured by anorectal manometry in mmHg
8 secondary outcomes
Anal sphincter electromyography (EMG)
Time frame: Baseline
Rectal compliance measured with a barostat
Time frame: Baseline
Rectal Capacity measured with a barostat
Time frame: Baseline
Rectal contractile response to distention measured with a sinusoidal oscillator
Time frame: Baseline
Rectal sensory threshold for first sensation to defecate using barostat balloon distention
Time frame: Baseline
Rectal sensory threshold for desire to defecate using barostat balloon distention
Time frame: Baseline
Rectal sensory threshold for maximum urgency during barostat balloon distention
Time frame: Baseline
Rectal balloon expulsion time
Time frame: Baseline
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 21 Aug 2026.
- Mayo Clinic Clinical TrialsLink provided by the sponsor.
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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.
Adil E Bharucha, MD principal investigator
Mayo Clinic
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Rectal Barostat Study and Fecoflowmetry in people with Constipation, run by Mayo Clinic 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 6 inclusion and 7 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 21 Aug 2026. 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. 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 Kelly J Feuerhak (507-255-6802, Feuerhak.Kelly@mayo.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rectal emptying (time frame: Baseline). The study lists 2 primary outcomes in all. 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 21 Aug 2026.