Condition category
Nervous System Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Urinary catheters are soft tubes put into the bladder to drain and then collect urine. In the UK, an average of 1 in 1000 people use long-term indwelling catheters. People using these catheters can experience complications, like blockages (where the urine does not drain into the catheter bag properly), urinary infections, pain, and a type of incontinence called catheter bypass. These complications can affect a person’s quality of life. They may also mean more emergency visits with nurses and GPs. Research shows that people consider blockage to be one of the most troubling aspects of using catheters over a long period. In current standard catheter care, catheter blockages are dealt with by either changing the catheter more often and/or using catheter washout liquids to washout the catheter. Some people are advised to do a catheter washout every week to try to reduce blockages. Others are not. The difference is because at present, there is no clear evidence to show whether doing regular washouts helps avoid blockages. People doing washouts also use different solutions. One is a weak salty (saline) solution, and the other is a citric mix, more like weak lemon juice. Both solutions are used in the NHS but it is not known which works best. The aim of this study is to find out the best way to reduce the number of blockages that can happen in people who have long-term indwelling catheters to find out if washing out the catheter every week using catheter washout liquids reduces catheter blockages and other problems like urinary incontinence or urinary tract infections.

Who can participate?
Adult men and women who have been using a catheter for ≥ 28 days and for whom there is no plan for discontinuation of catheter use at the time of recruitment, who are able to or has someone who can do catheter washouts for them.

What does the study involve?
Participants are randomly allocated to one of three groups for 24 months:
1. Weekly normal saline catheter washouts plus standard care
2. Weekly acidic (citric) catheter washouts plus standard care
3. Standard care only (i.e. no catheter washouts)
Participants are given a special calendar to record any problems with their catheter. They are contacted each month by a member of the research team who asks about any catheter-related problems they may have had. Every six months, participants are asked to complete a questionnaire about their quality of life and satisfaction with treatment.

What are the possible benefits and risks of participating?
Participants will receive the same level of care from their healthcare team whether or not they take part in the study. Participants may not benefit personally from taking part, but will be directly helping us to improve the care of patients with a long-term catheter in the future.
The washout solutions used in the study are already being used in the NHS. There may be a possible increase in the risk of urine infection when doing regular catheter washouts. The researchers will monitor this closely within the study and will ask participants about urine infections during every follow-up in the study. There are some side-effects from the long-term use of catheters but the researchers do not think that the risk will be increased by introducing regular washouts.

Where is the study run from?
University of Aberdeen (UK)

When is the study starting and how long is it expected to run for?
October 2019 to March 2023

Who is funding the study?
National Institute for Health Research (NIHR) (UK)

Who is the main contact?
Dr Lynda Constable

Trial website

Contact information



Primary contact

Prof Mohamed Abdel-Fattah


Contact details

School of Medicine
Medical Sciences and Nutrition
University of Aberdeen
Second Floor
Aberdeen Maternity Hospital
AB25 2ZH
United Kingdom
+44 (0)1224 438424



Additional contact

Dr Lynda Constable


Contact details

Centre for Healthcare Randomised Trials (CHaRT)
3rd Floor
Health Sciences Building
University of Aberdeen
AB25 2ZD
United Kingdom
+44 (0)1224 438144/8174



Additional contact

Dr Diana Johnstone


Contact details

Centre for Healthcare Randomised Trials (CHaRT)
3rd Floor
Health Sciences Building
University of Aberdeen
AB25 2ZD
United Kingdom
+44 (0)1224 438144/8174

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number

CPMS: 41284

Study information

Scientific title

Randomised controlled trial comparing the clinical and cost-effectiveness of various washout policies versus no washout policy in preventing catheter-associated complications in adults living with long-term catheters



Study hypothesis

In the UK, it is estimated that approximately 1 in 500 people live with a long term catheter. A urinary catheter is a thin, soft, flexible tube inserted into the bladder to drain urine to a collection bag. LTCs can be associated with complications including catheter blockage and urinary tract infections. Catheter blockages affect 50% of people with LTCs. Blockage and infection can impact upon quality of life and NHS resources.

There are two broad strategies for preventing and managing catheter blockage: more frequent change of catheter and/or the use of liquid solutions to washout or flush the catheters. We do not know enough about the benefits, harms or costs of regular prophylactic washouts, to recommend whether or not they should be standard care.

In this study the researchers will determine the clinical and cost-effectiveness, acceptability, satisfaction, and safety of weekly prophylactic catheter washout policies in addition to standard LTC care compared to standard LTC care only for adults living with LTC. The primary outcome is catheter blockage requiring intervention. The primary economic outcome is the incremental cost per quality adjusted life year (QALY) gained for each washout policy compared to standard LTC care only.

Ethics approval

Approved 22/03/2019, Wales REC6 (Health and Care Research Wales) (Wales National Pool, Sketty Lane, Swansea SA2 8QG; Tel: +44 (0)1267 611164, 01874 615949; Email:, ref: 19/WA/0015

Study design

Randomised; Both; Design type: Prevention, Device, Qualitative

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 to request a patient information sheet


Catheter-associated complications


The researchers are recruiting 600 people who have a LTC from primary care, secondary care and care homes. They are randomising participants to one of three groups:
1. Saline washouts. A policy of weekly prophylactic normal saline catheter washouts plus standard LTC care
2. Acidic washouts. A policy of weekly prophylactic acidic (citric) catheter washouts plus standard LTC care
3. Standard LTC care only (i.e. no prophylactic catheter washouts)

The researchers are following participants for 24 months to assess catheter blockages, infections, and complications, plus their quality of life, satisfaction, costs to the participant and NHS. They are exploring the views, attitudes, experiences and expectations of washouts with participants, nurses, and doctors.

Intervention type



Drug names

Primary outcome measure

Any catheter blockage requiring intervention up to 24 months post randomisation, from the question ‘Have you had any catheter blockages since we last spoke to you?’ from patient-reported monthly phone call CRF (monthly for 24 months) (Intervention is defined as any of the following: unplanned catheter removal or change or washout performed by the participant/ designated person or required unplanned visits to/from any healthcare provider, or hospital admission)

Secondary outcome measures

1. S-CAUTI requiring antibiotics use from the questions ‘Have you had a urine infection since we last spoke to you?’ and ‘How many infections required antibiotics?’ from patient-reported monthly phone call CRF (monthly for 24 months)
2. Duration of LTC in situ, catheter change due to other reasons than blockage; from the questions ‘Has there been discontinuation of long-term catheter use?’, ‘For the (reported problem), what treatment did you have?’ and Answers ‘Catheter change’ from patient-reported monthly phone call CRF (monthly for 24 months)
3. Adverse events; where participant has reported a treatment in the patient-reported monthly phone call CRF (monthly for 24 months) and the question of the clinical team is asked ‘Is this a SAE? Please tick’
4. Hospital admissions, GP/nurse outpatient visits for catheter-related complications from the questions ‘Since we last spoke to you, have you had to stay in hospital overnight for any of the problems related to your catheter?’, ‘For the (reported problem), where did you have treatment or a consultation with a doctor or nurse?’ and possible answers ‘GP at home, Nurse at home, care home staff, GP at surgery, Nurse at practice, Self/informal carer, Staff at hospital’ from patient-reported monthly phone call CRF (monthly for 24 months)
5. Generic quality of life assessed by EQ-5D-5L17 (EuroQol questionnaire – 5 dimensions – 5 levels) patient-reported questionnaire; Timepoint(s): 0, 6, 12, 18, 24 months post-randomisation
6. Condition-specific quality of life assessed by ICIQ-LTCqol18 (International Consultation on Incontinence Modular Questionnaire – Long Term Catheter quality of life) patient-reported questionnaire; Timepoint(s): 0, 6, 12, 18, 24 months post-randomisation
7. Adherence to allocated interventions; from the questions ‘Have you done a weekly washout since we last called you ?’, ‘Have you had any problems with the weekly washout?’, ‘Has your clinical care team recommended a change in washout frequency?’, ‘Has your clinical care team recommended a change in type of washout solution?’ and ‘Have you done any regular (preventative) washouts since we last called you?’ from patient-reported monthly phone call CRF (monthly for 24 months)
8. Patients’ convenience and satisfaction assessed by an adapted version of the abbreviated Treatment Satisfaction Questionnaire for medication; Timepoint(s): 0,6,12,18,24 months post-randomisation patient-reported questionnaire
9. Impact on day to day activities using the General Self-Efficacy Scale (GSE)20 and ICECAP-A (ICEpop CAPability measure for Adults) (≤ 65 years) or ICECAP-O21 (ICEpop CAPability measure for Older people) > 65 years patient-reported questionnaire; Timepoint(s): 0, 6, 12, 18, 24 months post-randomisation
10. Time and travel costs for patients and their relatives, friends or informal carers, from patient-reported questionnaire questions ‘We wish to know how much money and time were spent by you and any companion in attending health care appointments or being admitted to hospital’, including travel costs, time and whether or not accompanied by another person.; Timepoint(s): 18 months post-randomisation

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged ≥18 years
2. Catheter has been in-situ for ≥28 days
3. No plan for discontinuation of LTC at the time of recruitment
4. Able to undertake catheter washouts or has a designated person able to perform washouts
5. Able to complete the trial documentation or has a proxy able to complete the trial documentation
6. Any type and route of LTC can be included

Participant type


Age group




Target number of participants

Planned Sample Size: 600; UK Sample Size: 600

Participant exclusion criteria

1. Intermittent self-catheterisation
2. Pregnant or contemplating pregnancy
3. Spinal cord injury at or above the sixth thoracic vertebra (T6) (risk of Autonomic Dysreflexia - AD)
4. Ongoing S-CAUTI (until treatment is complete)
5. Visible hematuria (unless investigated/ treated)
6. Known allergies to either of the catheter washout solutions
7. Current bladder cancer (until treatment is complete and patient discharged from cancer surveillance program)
8. Known bladder stones (until treatment is complete)
9. Any other clinical and social reasons that would be deemed by the recruitment team to be unsuitable for the study

If a participant stops using a long-term catheter (no catheter in situ) >=28 days. All data collected up to the point of stopping long term catheter use are retained and used in the analysis

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

NHS Grampian
Summerfield House 2 Eday Road
AB15 6RE
United Kingdom

Trial participating centre

Northumbria Healthcare NHS Foundation Trust
Nursery Park Nursery Road
NE63 0HP
United Kingdom

Trial participating centre

West Rainton Surgery
Woodland View West Rainton
United Kingdom

Trial participating centre

Great Lumley Surgery
Front Street Great Lumley
United Kingdom

Trial participating centre

The Haven Surgery
The Haven
United Kingdom

Sponsor information


NHS Grampian

Sponsor details

AB15 6RE
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type


Funder name

NIHR Evaluation, Trials and Studies Co-ordinating Centre (NETSCC); Grant Codes:

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

The protocol will be publicly available on the study website and the NIHR HTA website. The researchers intend to publish the study protocol as soon as is practicable.

IPD sharing statement
The data sharing plans for the current study are unknown and will be made available at a later date.

Intention to publish date


Participant level data

To be made available at a later date

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

04/09/2020: Recruitment to this study is no longer paused. 16/04/2020: Due to current public health guidance, recruitment for this study has been paused. 16/04/2020: NHS Lothian has been removed and Northumbria Healthcare NHS Foundation Trust, West Rainton Surgery, Great Lumley Surgery and The Haven Surgery have been added as trial participating centres. 04/11/2019: Trial's existence confirmed by the NIHR.