ISRCTN ISRCTN15446376
DOI https://doi.org/10.1186/ISRCTN15446376
Secondary identifying numbers V1; 13/4/14
Submission date
15/04/2015
Registration date
29/04/2015
Last edited
09/07/2020
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Circulatory System
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Record updated in last year

Plain English summary of protocol

Background and study aims
Obesity is a term used to describe somebody who is very overweight, with a lot of body fat. It's a common problem, estimated to affect around one in every four adults and around one in every five children aged 10 to 11 in the UK. People who are obese are at risk of a number of serious and potentially life-threatening conditions, such as high blood pressure. High blood pressure is dangerous because it can have no symptoms, and increases the risk of a heart attack or stroke. It can also cause permanent damage to vital organs, such as the kidney, eye, brain and heart. Normally, high blood pressure can be treated with medications but these medications don’t work very well in obese patients and we’re not sure why. Most information on blood vessel structure comes from blood vessels studied in a laboratory. Here, we are using a technique which allows us to view blood vessels in the patient directly. Eye (retinal) blood vessel analysis is a non-invasive way to measure the structure of small blood vessels in a patient. The aim of this study is to get a better understanding of the differences in small blood vessel structure between obese patients and lean patients.

Who can participate?
Adults with a BMI over 30 or lower than 25.

What does the study involve?
Participants have non-invasive tests to check how well their blood vessels are functioning. Two of these tests are eye tests. There is also a blood test.

What are the possible benefits and risks of participating?
There are no risks or benefits to participating in this study.

Where is the study run from?
Wellcome Trust Clinical Trials Facility, Central Manchester University Hospitals Trust (UK)

When is the study starting and how long is it expected to run for?
June 2015 to January 2017

Who is funding the study?
British Heart Foundation (UK)

Who is the main contact?
Dr A Greenstein (scientific)

Contact information

Dr Adam Greenstein
Scientific

Institute of Cardiovascular Sciences
University of Manchester
Core Technology Facility
Grafton Street
Manchester
M13 9PL
United Kingdom

Phone +44 (0) 161 275 1202
Email adam.greenstein@manchester.ac.uk

Study information

Study designSingle site cohort observation
Primary study designObservational
Secondary study designCohort study
Study setting(s)Hospital
Study typeScreening
Participant information sheet Not available in web format, please use contact details to request a participant information sheet.
Scientific titleIdentification of cardiovascular changes in obesity using dynamic and static retinal vessel analysis
Study objectivesChanges in retinal vessel function can be correlated with obesity, blood pressure, pulse wave velocity and blood metabolic markers.
Ethics approval(s)North West - Greater Manchester South Research Ethics Committee, 29/07/2015 ref: 15/NW/0548
Health condition(s) or problem(s) studiedCardiovascular disease associated with obesity
InterventionAll participants who express an interest in study participation will be invited to attend Manchester Clinical Research Facility. Following informed consent procedure (estimated to take approximately 15mins), all participants will undergo:
1. Assessment of past medical history and physical examination: height, weight, waist circumference (10 mins)
2. Pupil dilation (Tropicamide eye drops applied taking 2 minutes to perform but up to 20 minutes to take effect)
3. Blood sampling – up to 10ml (2 teaspoon blood) takes up to 10mins to perform
4. Pulse Wave velocity measurement lay in supine position (10 mins)
5. Blood pressure will be recorded at the start and end of procedure but also throughout the assessment using a wrist cuff
6. Dynamic retinal vessel analysis (flicker stimulation) (15 mins)
7. Static retinal vessel analysis (10 mins)
8. Oxygen saturation will be measured by taking a photograph of the fundus of the eye (5 mins)
9. Carbon dioxide inhalation – during the imaging examination of the eye, a mixture of 95% air/5% carbon dioxide will be administered via nasal cannula (procedure takes 2-3 minutes but gas will be administered for only 45 seconds)
10. On completion of the assessment, participants will be given the general advice leaflet for Tropicamide and advised not to drive for 4 hours This completes study participation.
Total duration of assessment not expected to be more than 2 hours.
Intervention typeOther
Primary outcome measureVascular function measured by degree of response to flicker stimulation, retinal arteriolar-venular ratio (AVR) and blood oxygen saturation on the assessment day.
Secondary outcome measuresPeripheral measurements: blood pressure, pulse wave velocity and blood levels of HbA1c and blood lipids (triglycerides, LDL and HDL cholesterol) on the assessment day.
Overall study start date01/02/2015
Completion date31/12/2020

Eligibility

Participant type(s)Mixed
Age groupAdult
SexBoth
Target number of participants30 healthy lean controls and 30 obese patient-participants
Key inclusion criteriaPatient-participants:
1. Willing and capable to provide consent to participation
2. BMI greater than 30
3. No known ocular diseases
4. No known concurrent clinical problem likely to interfere with participation or completion of the study

Healthy controls:
1. BMI lower that 25
2. No known diabetes
3. No known ocular diseases
4. No known concurrent clinical problem likely to interfere with participation or completion of the study
Key exclusion criteria1. Under 18 years old
2. Intubated/ventilated patients
3. Unwilling to give consent to participation OR advised by consultee that this would be against the patient’s wishes
4. Smoker
5. If eaten with in an hour of the examination
6. If drank alcohol within an hour of the examination
7. If drank coffee within an hour of the examination
8. If overly hungry
9. Recently treated infection
10. Known ocular diseases
11. Known concurrent clinical problem likely to interfere with participation or completion of the study

Additional exclusion for healthy controls:
1. Diabetes
2. BMI above 25
Date of first enrolment01/06/2015
Date of final enrolment30/06/2020

Locations

Countries of recruitment

  • England
  • United Kingdom

Study participating centre

Manchester Clinical Research Facility
Oxford Road
Manchester
M13 9WL
United Kingdom

Sponsor information

The University of Manchester
University/education

Oxford Road
Manchester
M13 9PT
England
United Kingdom

Phone +44 (0) 161 275 5436
Email fmhsethics@manchester.ac.uk
ROR logo "ROR" https://ror.org/027m9bs27

Funders

Funder type

Government

National Institute for Health Research
Government organisation / National government
Alternative name(s)
National Institute for Health Research, NIHR Research, NIHRresearch, NIHR - National Institute for Health Research, NIHR (The National Institute for Health and Care Research), NIHR
Location
United Kingdom

Results and Publications

Intention to publish date31/12/2021
Individual participant data (IPD) Intention to shareYes
IPD sharing plan summaryAvailable on request
Publication and dissemination planPlanned publication in a peer reviewed journal.
IPD sharing planThe datasets generated during and/or analysed during the current study are/will be available upon request from adam.greenstein@manchester.ac.uk

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
HRA research summary 28/06/2023 No No

Editorial Notes

09/07/2020: The trial contact details have been made publicly visible.
01/06/2017: The following changes have been made to the record:
1. The overall trial dates have been updated from 01/06/2015 - 31/01/2017 to 01/02/2015 - 31/12/2020
2. The recruitment end date has been updated from 31/01/2017 to 30/06/2020
3. The name of the trial participating centre has been changed from Wellcome Trust Clinical Trials Facility to Manchester Clinical Research Facility
4. The funder has been changed from British Heart Foundation to the National Institute for Health Research
5. The interventions and IPD sharing statement have been added
24/03/2016: Ethics approval information added.