Trial Outcomes & Findings for A Placebo-Controlled Trial of St. John's Wort for Irritable Bowel Syndrome (NCT NCT00587860)

NCT ID: NCT00587860

Last Updated: 2010-03-09

Results Overview

The primary end point was the overall self-reported BSS after 12 weeks of therapy for all randomized participants to assess for differences between treatment groups at the end of the treatment period (12 weeks). The BSS is a 100-mm visual analog scale for the different symptoms of IBS (pain/discomfort, constipation, diarrhea, and overall severity). Symptoms on the BSS can range from 0 = no pain to 100 = extreme pain.

• Recruitment status: COMPLETED
• Study phase: PHASE2
• Target enrollment: 70 participants
• Primary outcome timeframe: After 12 weeks of treatment
• Results posted on: 2010-03-09

Participant Flow

Participants were identified through community, institutional advertisement, clinicaltrials.gov, through the IFFGD webpage as well as through the outpatient clinics beginning in February 2006. Participants who participated in previous IBS studies were also mailed a recruitment letter to ask if they would be interested in participating.

For this study, there was a 2-week screening and enrollment phase. During this period, participants were screened, a symptom questionnaire was completed, and there was a physician exam. After the in-person screening visit, a phone call was made prior to mailing the study materials to ensure the participant was still willing to participate.

Participant milestones

Measure	St. John's Wort St. John's Wort, 450 mg twice a day	Placebo Placebo, twice a day
Overall Study STARTED	35	35
Overall Study COMPLETED	30	30
Overall Study NOT COMPLETED	5	5

Reasons for withdrawal

Measure	St. John's Wort St. John's Wort, 450 mg twice a day	Placebo Placebo, twice a day
Overall Study Lost to Follow-up	2	2
Overall Study Withdrawal by Subject	3	3

Baseline Characteristics

A Placebo-Controlled Trial of St. John's Wort for Irritable Bowel Syndrome

Baseline characteristics by cohort

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day	Total n=70 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Age, Categorical Between 18 and 65 years	33 Participants n=5 Participants	35 Participants n=7 Participants	68 Participants n=5 Participants
Age, Categorical >=65 years	2 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants
Age Continuous	42.2 years STANDARD_DEVIATION 14.34 • n=5 Participants	39.43 years STANDARD_DEVIATION 11.26 • n=7 Participants	40.81 years STANDARD_DEVIATION 12.87 • n=5 Participants
Sex: Female, Male Female	30 Participants n=5 Participants	30 Participants n=7 Participants	60 Participants n=5 Participants
Sex: Female, Male Male	5 Participants n=5 Participants	5 Participants n=7 Participants	10 Participants n=5 Participants
Region of Enrollment United States	35 participants n=5 Participants	35 participants n=7 Participants	70 participants n=5 Participants
Bowel Symptom Score (BSS)	173 Units on a scale n=5 Participants	165 Units on a scale n=7 Participants	169 Units on a scale n=5 Participants
Center for Epidemiologic Studies Depression Scale (CES-D) score	6 Units on a scale n=5 Participants	5 Units on a scale n=7 Participants	5.5 Units on a scale n=5 Participants
Irritable Bowel Syndrome - Quality of Life (IBS-QoL)	23 Units on a scale n=5 Participants	20 Units on a scale n=7 Participants	21.5 Units on a scale n=5 Participants

PRIMARY outcome

Timeframe: After 12 weeks of treatment

Population: Analysis is based on the intention to treat (ITT) paradigm, including all randomized patients. Assuming standard deviation of the overall BSS symptom score is \~75, then 35 per group provides 80% power to detect about a 50% difference which is based on a 2-sample t-test assuming the distribution of Bowel Symptom Survey (BSS) values.

The primary end point was the overall self-reported BSS after 12 weeks of therapy for all randomized participants to assess for differences between treatment groups at the end of the treatment period (12 weeks).

The BSS is a 100-mm visual analog scale for the different symptoms of IBS (pain/discomfort, constipation, diarrhea, and overall severity). Symptoms on the BSS can range from 0 = no pain to 100 = extreme pain.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Overall Bowel Symptom Scores (BSS)	76 Scores on a scale Interval 4.0 to 165.0	44 Scores on a scale Interval 0.0 to 125.0

SECONDARY outcome

Timeframe: 12 weeks

Population: Analysis is based on the intention to treat (ITT) paradigm, including all randomized patients. Assuming standard deviation of the overall BSS symptom score is \~75, then 35 per group provides 80% power to detect about a 50% difference which is based on a 2-sample t-test assuming the distribution of Bowel Symptom Survey (BSS) values.

Median (average) BSS amongst the different IBS subgroups (diarrhea, constipation, pain, and bloating). The BSS is a 100-mm visual analog scale for the different symptoms of IBS (pain/discomfort, constipation, diarrhea, and overall severity). Symptoms on the BSS can range from 0 = no pain to 100 = extreme pain.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Bowel Symptom Score (BSS) Amongst Subgroups BSS for diarrhea subgroup	32 Scores on a scale Interval 0.0 to 92.0	17 Scores on a scale Interval 0.0 to 94.0
Bowel Symptom Score (BSS) Amongst Subgroups BSS for constipation subgroup	25.8 Scores on a scale Interval 0.0 to 78.0	16 Scores on a scale Interval 0.0 to 84.0
Bowel Symptom Score (BSS) Amongst Subgroups BSS for pain subgroup	35.8 Scores on a scale Interval 1.0 to 77.0	23.5 Scores on a scale Interval 0.0 to 77.0
Bowel Symptom Score (BSS) Amongst Subgroups BSS for bloating subgroup	30.3 Scores on a scale Interval 2.0 to 75.0	23.8 Scores on a scale Interval 1.0 to 70.0

SECONDARY outcome

Timeframe: Last 4 weeks of therapy

Participants who reported "yes" or "no" to having adequate relief of their IBS symptoms at least 50% during the last 4 weeks of therapy.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Adequate Relief ≤ 50% During the Last 4 Weeks of Therapy Yes	32 Percentage of Participants	62 Percentage of Participants
Adequate Relief ≤ 50% During the Last 4 Weeks of Therapy No	50 Percentage of Participants	26 Percentage of Participants
Adequate Relief ≤ 50% During the Last 4 Weeks of Therapy Missing	18 Percentage of Participants	12 Percentage of Participants

SECONDARY outcome

Timeframe: 12 weeks of treatment

The IBS-QOL is a self-report quality-of-life measure specific to Irritable Bowel Syndrome (IBS) that can be used to assess the impact of IBS and its treatment. The IBS-QOL was measured at baseline, week 12 and week 24. The individual responses to the 34 items are summed and averaged for a total score and then transformed to a 0-100 scale for ease of interpretation with higher scores indicating better IBS specific quality of life.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Irritable Bowel Syndrome - Quality of Life (IBS-QoL) Score	18.8 Units on a scale Interval 0.7 to 69.8	14.7 Units on a scale Interval 1.5 to 75.0

SECONDARY outcome

Timeframe: 12 weeks

We measured CES-D Score at baseline as well as bi-weekly throughout the study. The CES-D is a self-reported 20 question survey designed to measure depressive symptomatology in the general population. The possible range of scores is zero to 60, with the higher scores indicating the presence of more symptomatology.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Center for Epidemiologic Studies Depression Scale (CES-D) Score	2 Units on a scale Interval 0.0 to 26.0	3 Units on a scale Interval 0.0 to 29.0

SECONDARY outcome

Timeframe: 24 weeks

Number of participants who stated their IBS symptoms were moderately better or a lot better at 24 weeks.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
IBS Symptoms Moderately or a Lot Better Yes	5 participants	5 participants
IBS Symptoms Moderately or a Lot Better No	24 participants	25 participants
IBS Symptoms Moderately or a Lot Better Missing	6 participants	5 participants

SECONDARY outcome

Timeframe: 24 weeks

We measured CES-D Score at baseline as well as bi-weekly throughout the study. The CES-D is a self-reported 20 question survey designed to measure depressive symptomatology in the general population. The possible range of scores is zero to 60, with the higher scores indicating the presence of more symptomatology.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Center for Epidemiologic Studies Depression Scale (CES-D) Score	3.0 Units on a scale Interval 0.0 to 16.0	2.5 Units on a scale Interval 0.0 to 30.0

SECONDARY outcome

Timeframe: 24 weeks

The BSS is a five question, 100-mm visual analog scale of four IBS symptoms (pain/discomfort, bloating, constipation, and diarrhea), and an overall severity scale. The best possible value would be 0 (no symptoms) and the worst is 500 (severe symptoms). BSS was assessed on a bi-weekly basis.

Outcome measures

Measure	St. John's Wort n=35 Participants St. John's Wort, 450 mg twice a day	Placebo n=35 Participants Placebo, twice a day
Bowel Symptom Score (BSS) at 24 Weeks	65 Units on a scale Interval 12.0 to 149.0	60 Units on a scale Interval 11.0 to 152.0

Adverse Events

St. John's Wort

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Placebo

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Yuri A. Saito Loftus, M.D., M.P.H.

Mayo Clinic

Phone: 507-284-5010

Email: saito.yuri@mayo.edu

Results disclosure agreements

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