Condition category
Urological and Genital Diseases
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Patients with kidney disease need dialysis to replace the work their kidneys are not able to do. One of the types of dialysis available is called Peritoneal Dialysis (PD). It relies on a special fluid being drained in and out of the patient’s body. If a PD patient becomes constipated, this fluid cannot drain out properly. As a result, the dialysis process stops working. All PD patients are given laxatives to prevent them from becoming constipated. Rather than rely on laxative medicine, this study aimed to improve the intake of dietary fibre as a means of preventing constipation.

Who can participate?
All adult patients on PD were invited to take part if they were using laxatives regularly and wanted to try an alternative.

What does the study involve?
Patients were randomly put into one of three groups. The first group was given dietary fibre in the form of a white powder that dissolved easily in drinks and soft food. The second group was given a white powder that looked the same but had no fibre. This is called a placebo. These two groups did not know which of the powders they had been given. They were told to mix the powder with any drink or food each day for 4 weeks. They had to start gradually in case the powder caused them any discomfort. They were told to continue taking their usual laxatives until they could tell that the powder was having an effect. They were shown how to measure the effect the powder might be having by looking at their stools. If their stools became looser, they were told to reduce their laxatives but keep going with the powder. The third group were given a special diet chart that listed foods containing dietary fibre that were safe for kidney patients to eat. They were told to try and include six to nine items from the list every day to see if they could improve their intake of dietary fibre using normal food.

What are the possible benefits and risks of participating?
The advantage of taking part would be to use a more natural way of controlling bowel function rather than relying on medication. There were no risks involved with this trial. None of the interventions required patients to make changes to their existing therapeutic dietary advice or their medication.

Where is the study run from?
The study was designed by one of the Renal Dietitians and originally tried out in Portsmouth. It was then extended to include other renal units across England. These were Kings College London, York, Royal Berkshire, Sheffield, Exeter, Truro, Plymouth, Kent and Canterbury. In all cases, the work was carried out by one of the Renal Dietitians on each Unit.

When is the study starting and how long is it expected to run for?
The study ran from March 2009 to August 2010.

Who is funding the study?
The study was funded by a grant from the British Renal Society.

Who is the main contact?
Debbie Sutton, Renal Research Dietitian

Trial website

Contact information



Primary contact

Mrs Debbie Sutton


Contact details

Portsmouth - Queen Alexandra Hospital
Renal Unit
United Kingdom
+44 23 9228 6000

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A multicentre randomised trial to assess whether increased dietary fibre intake (using a fibre supplement or high fibre foods) reduces laxative requirement in free living Peritoneal Dialysis patients


Study hypothesis

The main aim of this study is to investigate whether a daily bowel habit of appropriate consistency may be achieved through a higher fibre diet and minimal use of laxatives.

We will conduct the study to:
1. Establish current bowel habits, fibre intake, laxative use and costs, and the prevalence of constipation among all peritoneal dialysis (PD) programme patients
2. Test whether an increase in dietary fibre intake by 6 - 12 g per day (using a fibre supplement or high fibre food) results in improved bowel habits and reduced laxative use
3. Ensure that the treatment has no adverse effects on fluid balance or laboratory parameters (potassium, phosphate)
4. Investigate whether an increased fibre intake improves lipid profile

Ethics approval

Portsmouth IOW and SE Hants REC approved on the 18/12/2008 (ref: 08/H0501/123)

Study design

Multicentre randomised interventional treatment trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Topic: Renal and Urogenital; Subtopic: Renal and Urogenital (all Subtopics); Disease: Renal


1. Fibre supplement arm
2. High dietary fibre arm
3. Placebo arm

The length of study period in each arm is 4 weeks.

Intervention type



Not Applicable

Drug names

Primary outcome measure

Regular bowel activity, measured once at the end of the 4 week intervention period

Secondary outcome measures

1. Has stopped their laxatives
2. Stools equal to 3, 4 or 5 on the Bristol Stool Form

Measured once at the end of the 4 week intervention period.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. PD patient for minimum 3 months
2. Regular user of laxatives
3. Aged greater than 18 years, either sex

Participant type


Age group




Target number of participants

Planned sample size: 100

Participant exclusion criteria

Does not meet inclusion criteria

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Portsmouth - Queen Alexandra Hospital
United Kingdom

Sponsor information


Portsmouth Hospitals NHS Trust (UK)

Sponsor details

Southwick Hill Road
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type

Research organisation

Funder name

British Renal Society

Alternative name(s)


Funding Body Type

private sector organisation

Funding Body Subtype

Associations and societies (private and public)


United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

30/08/2016: No publications found in PubMed, verifying study status with principal investigator.