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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
A randomised controlled trial of a brief self-help intervention for post infectious irritable bowel syndrome (IBS)
Scientific title
A randomised controlled trial of a brief self-help cognitive behavioural therapy intervention for symptom relief in post infectious irritable bowel syndrome (IBS)
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Post infectious irritable bowel syndrome (IBS) 374 0
Condition category
Condition code
Oral and Gastrointestinal 443 443 0 0
Studies of infection and infectious agents

Study type
Description of intervention(s) / exposure
Patients in this study were randomised to receive either a brief self-help intervention based on cognitive behavioural therapy (CBT) principles or standard medical care across the same seven week period. The self-help intervention developed specifically for this study consists of a structured manual divided into seven weekly sessions. The first chapter provides a detailed biopsychosocial model of IBS that explains why patients continue to experience symptoms after their initial infection and justifies the approach used in the manual. The remaining chapters provide behavioural guidelines for managing diarrhoea and constipation, advice on behavioural change for diet and exercise, cognitive strategies to challenge unhelpful thoughts or beliefs about symptoms, identifying and managing perfectionism, as well as stress and sleep management. Patients received the manual together with an initial face-to-face session with a CBT therapist explaining the programme and the model of IBS and two one-hour phone call follow-ups at 3 and 5 weeks into the programme with the same therapist.
Intervention code [1] 218 0
Comparator / control treatment
Standard medical care.
Patients in the standard medical care group received a detailed assessment by a specialist general practitioner (GP) to determine if they met Rome criteria for IBS, a fact sheet explaining why they have been diagnosed with IBS and a recommendation to consult with their own GP for further treatment options.
Control group

Primary outcome [1] 501 0
The Subjects Global Assessment of Relief (Muller-Lissner et al. (2003) which has been developed as a primary assessment of outcome in clinical studies of IBS with the intention of identifying responders to therapy
Timepoint [1] 501 0
Measured at the end of treatment, and 3 and 6 months follow-up
Primary outcome [2] 502 0
The Irritable Bowel Symptom Severity Scoring System (Francis et al., 1997) which provides an indication of bowel symptom severity
Timepoint [2] 502 0
Measured at baseline, end of treatment, 3 and 6 months follow-up
Secondary outcome [1] 1084 0
The Work and Social Adjustment Scale (WSAS) (Mundt et al 2002), is used to measure the impact of IBS on the person’s day to day life.
Timepoint [1] 1084 0
Measured at baseline, end of treatment, 3 and 6 months follow–up.
Secondary outcome [2] 1085 0
The Hospital Anxiety and Depression scale (HAD) (Zigmond 1983) is used to assess the degree of anxiety and depression.
Timepoint [2] 1085 0
Measured at baseline, end of treatment, 3 and 6 months follow–up.

Key inclusion criteria
(a) a diagnosis of IBS based on Rome I modified and/or Rome II criteria. (b) a diagnosis of IBS subsequent to an episode of gastroenteritis (c) between the ages of 18-70 (d) primary care attendees in the greater Auckland area.
Minimum age
18 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
(a) Patients who have another medical condition that may affect their symptoms or preclude a diagnosis of IBS such as previous bowel surgery or a malignancy, ceoliac disease, inflammatory bowel disease, or obstructive bowel pathology (b) Patients who have any serious psychological disorders for whom treatment would be inappropriate including psychotic disorders or active substance abuse. (c). Non-English speakers and people who are unable to read and write English. (d) Should any participants alter their medication during this time period, or begin a course of anti-depressant medication their data will not be included in the final analysis. (e) Inclusion in another treatment trial.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Randomisation was achieved by placing equal numbers of the words ⿿control⿿ or ⿿treatment⿝ in 80 separate, opaque envelopes which were ordered according to random numbers and then sealed. These were kept in order by an independent administrator. As each new participant entered the study, the independent administrator opened the envelope on the top of the pile and informed the participant of their group allocation.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Through a computerised randomisation programme.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 140 0
New Zealand
State/province [1] 140 0

Funding & Sponsors
Funding source category [1] 494 0
Name [1] 494 0
The University of Auckland Staff Grant
Address [1] 494 0
Country [1] 494 0
New Zealand
Primary sponsor type
Dr Rona Moss-Morris
Secondary sponsor category [1] 400 0
Name [1] 400 0
Dr Rosie Williamson
Address [1] 400 0
Country [1] 400 0
Secondary sponsor category [2] 401 0
Name [2] 401 0
Leona Didsbury
Address [2] 401 0
Country [2] 401 0
Secondary sponsor category [3] 402 0
Name [3] 402 0
Laura Bogalo
Address [3] 402 0
Country [3] 402 0
Secondary sponsor category [4] 403 0
Name [4] 403 0
Prof Trudie Chalder
Address [4] 403 0
Country [4] 403 0

Ethics approval
Ethics application status

Brief summary
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 35401 0
Address 35401 0
Country 35401 0
Phone 35401 0
Fax 35401 0
Email 35401 0
Contact person for public queries
Name 9407 0
Laura Bogalo
Address 9407 0
Psychological Medicine
Faculty of Medical and Health Sciences
University of Auckland
Private Bag 92019
Country 9407 0
New Zealand
Phone 9407 0
+64 9 3737599
Fax 9407 0
+64 9 3737013
Email 9407 0
Contact person for scientific queries
Name 335 0
Dr Rona Moss-Morris
Address 335 0
Psychological Medicine
Faculty of Medical and Health Sciences
University of Auckland
Private Bag 92019
Country 335 0
New Zealand
Phone 335 0
64 9 3737599 (Ext.) 86756
Fax 335 0
+64 9 3737013
Email 335 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary