Condition category
Urological and Genital Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Haemodialysis has been the standard treatment for patients with chronic kidney disease for more than 50 years, with almost 3 million patients treated worldwide. Despite advances in dialysis technology, the 5-year survival for patients treated by haemodialysis is much less than that of some common cancers; with heart disease being he commonest cause of death. Blood pressure is typically high before a dialysis session, and then falls as fluid is removed from patients during the dialysis session. Low blood pressure (hypotension) is the commonest complication of routine outpatient haemodialysis treatments, estimated to occur in 20-40% of all treatments. Hypotension during haemodialysis is associated with an increased risk of both mortality and also for the older patient an increased risk of developing frailty and need for help in looking after themselves. Haemodiafiltration (HDF) is a type of haemodialysis but increases the range of substances compared to haemodialysis (HD). Some studies have suggested that HDF treatments have a lower risk of hypotension, and reduce mortality from any cause, and in particular mortality from heart disease. The aim of this study is to determine whether there are differences in blood pressure and stiffness of arteries in patients treated by HDF compared to HD.

Who can participate?
This study is only open to patients already taking part in the United Kingdom High-flux Haemodialysis vs High-volume Haemodiafiltration Registry Trial (H4RT)

What does the study involve?
Apart from taking part in the H4RT, patients are asked to attend for two echocardiograms in 2 years, additional blood tests during three dialysis sessions in 2 years, wearing an ambulatory blood pressure machine three times in 2 years, having three bioimpedance measurements in 2 years, and completing a simple test of cognitive function (the same one which is used on the president of the USA as part of their annual health check) three times in 2 years.

What are the possible benefits and risks of participating?
As with many studies there is no immediate benefit, but the results of the study will help determine whether one type of kidney dialysis treatment is better than the other, and also potentially provide information about targets for blood pressure control for kidney dialysis patients. No additional risks are expected over and above attending for dialysis, as all tests are established in routine clinical practice.

Where is the study run from?
University College London (UK)

When is the study starting and how long is it expected to run for?
January 2017 to March 2022

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

Who is the main contact?
Prof. Andrew Davenport

Trial website

Contact information



Primary contact

Prof Andrew Davenport


Contact details

UCL Department of Nephrology
United Kingdom
+44 (0)2077940500

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

Study To Investigate The Change In Hypotensive Episodes during Dialysis (STITCHED)



Study hypothesis

That treatment of patients with kidney failure with higher volume on-line haemodiafiltration leads to fewer episodes of intra-dialytic hypotension than conventional high-flux haemodialysis.

Ethics approval

Approved 01/02/2019, East Midlands Leicester Central Research Ethics Committee (The Old Chapel
Royal Standard Place, Nottingham, NG1 6FS; Email:, REC ref: 18/EM/0212

Study design

Observational study nested within the UK H4RT trial

Primary study design


Secondary study design

Cohort study

Trial setting


Trial type


Patient information sheet

Not available in web format. For further information please contact trial manager


Kidney failure treated by haemodialysis


Measured at study entry and at 24 months:
1. Ambulatory blood pressure and pulse wave velocity
2. Trans-thoracic echocardiography
3. Bioimpedance
4. Montreal Cognitive Assessment
5. Beta-2 microglobulin clearance
6. Measurement of cardiac biomarkers

Intervention type



Drug names

Primary outcome measure

Intra-dialytic hypotensive episodes recorded quarterly

Secondary outcome measures

1. Ambulatory blood pressure measured at study entry, 12 months and completion at 24 months
2. Arterial stiffness measured using pulse wave velocity (pressure mmHg) at study entry, 12 months and completion at 24 months
3. Cognitive function assessed using Montreal cognitive assessment at study entry, 12 months and completion at 24 months
4. Extracellular water volumes measured using bioimpedance (volume L) at study entry, 12 months and completion at 24 months
5. Cardiac biomarkers measured using lab test at study entry, 12 months and completion at 24 months
6. Cardiac echocardiographic parameters and function measured using transthoracic echocardiogram at study entry and study completion at 24 months
7. Clearance of the middle molecule β2 microglobulin measured using lab test at study entry, 12 months and completion at 24 months

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Patients randomised to The UK High-flux Haemodialysis vs High-volume Haemodiafiltration Registry Trial (H4RT) National Institute Health Research (NIHR) Health Technology Assessment 15/80/52

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Not enrolled in H4RT study
2. Unable to provide informed consent

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Royal Free Hospital
Pond Street
United Kingdom

Sponsor information


University College London

Sponsor details

Gower St
United Kingdom
+44 (0)20 7679 2000

Sponsor type




Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

Main publication expected 2023

IPD sharing statement
On completion the data will be stored in UCL (University College London) library archive in anonymised form. Study data will be retained for 15 years. Consent forms do not have a statement agreeing that data can be used by other researchers. As this is a sub-study of the United Kingdom High-flux Haemodialysis vs High-volume Haemodiafiltration Registry Trial (H4RT), then requests to access data once the trial has finished and main papers published will by application to the United Kingdom High-flux Haemodialysis vs High-volume Haemodiafiltration Registry Trial (H4RT).

Intention to publish date


Participant level data

Stored in repository

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

02/04/2020: Due to current public health guidance, this study has been paused. 27/03/2019: Trial's existence confirmed by the NIHR.