SALT-SWAP - Testing different approaches to help people reduce their salt intake
| ISRCTN | ISRCTN20910962 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN20910962 |
| Protocol serial number | 33949 |
| Sponsor | University of Oxford |
| Funder | British Heart Foundation |
- Submission date
- 27/03/2017
- Registration date
- 05/04/2017
- Last edited
- 25/02/2022
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Circulatory System
Plain English summary of protocol
Background and study aims
High blood pressure increases the risk of heart disease and stroke and is a major cause of ill-health in the UK. There is evidence that eating too much salt can increase your blood pressure. The recommended salt intake for adults is less than 6g/day, but the average adult in the UK eats 8.1g/day. The majority of the salt people eat comes from packaged or processed foods. For many high-salt products there is a similar, lower-salt alternative but it can be difficult for shoppers to quickly identify these alternatives. The aim of this study is to test a new program to help people with high blood pressure to reduce their salt intake, by helping them choose lower-salt products when supermarket shopping.
Who can participate?
Adults with high blood pressure who regularly shop in a supermarket and own a smartphone.
What does the study involve?
Participants are randomly allocated to one of two groups. Those in the first group take part in the program to help them lower their salt intake. This consists of advice from a healthcare professional about salt and its effect on blood pressure and instructions to download and use a smartphone app which suggests lower-salt alternatives when grocery shopping. Those in the second group receive an information leaflet which contains tips and tools to help reduce salt intake.
What are the possible benefits and risks of participating?
Participants may benefit from reducing their salt intake. There are no notable risks involved with participating.
Where is the study run from?
The study is being run by Nuffield Department of Primary Care Health Sciences, University of Oxford and takes place in GP practices in Oxfordshire and the Thames Valley (UK)
When is the study starting and how long is it expected to run for?
November 2016 to March 2019
Who is funding the study?
British Heart Foundation (UK)
Who is the main contact?
Ms Sarah Payne Riches
sarahpayne001@yahoo.com
(updated 07/09/2021, previously: sarah.payneriches@phc.ox.ac.uk)
Contact information
Scientific
Radcliffe Observatory Quarter
Woodstock Road
Oxford
OX2 6GG
United Kingdom
 ORCID ID |
0000-0001-8804-9500 |
|---|---|
| Phone | +44 1865 289300 |
| sarahpayne001@yahoo.com |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Randomised; Interventional; Design type: Treatment, Prevention, Psychological & Behavioural, Complex Intervention |
| Secondary study design | Randomised controlled trial |
| Study type | Participant information sheet |
| Scientific title | Randomised controlled feasibility trial of a complex behavioural intervention to reduce salt intake among people with high blood pressure |
| Study acronym | SALT-SWAP |
| Study objectives | The aim of this study is to test a new intervention to help people with high blood pressure to reduce their salt intake, by helping them choose lower-salt products when supermarket shopping. |
| Ethics approval(s) | South Central – Hampshire B REC, 17/03/2017, ref: 17/SC/0098 Major amendment 1: 20/12/2017 Major amendment 2: 21/06/2018, Major amendment 3: 21/08/2018 Major amendment 4: 04/01/2019 |
| Health condition(s) or problem(s) studied | Hypertension |
| Intervention | Participants will be randomised to one of two groups using computer generated block randomisation. Intervention: Participants will receive a behavioural intervention consisting of one session of brief dietary and motivational advice, to be delivered by a health care professional (HCP) in primary care. In addition, participants will receive ongoing support at the point of choice while shopping using a mobile phone application (app), which will suggest lower salt alternatives, enable self-monitoring and provide feedback on salt content of purchases. The brief advice session by the HCP will last approximately 20 minutes. The intervention period will be 6 weeks. Control: Participants will receive an information and advice leaflet by post. This leaflet is produced by the British Heart Foundation and is called Cut Down on Salt and contains tips and tools to help reduce salt intake. There will be one follow up assessment which will occur in the week following the 6 week intervention period. Baseline assessment measures will be repeated and all participants will be also be asked to complete a short post-intervention questionnaire to assess aspects of the intervention (or control) they received. |
| Intervention type | Other |
| Primary outcome measure(s) |
Feasibility outcomes: |
| Key secondary outcome measure(s) |
1. Salt content of purchased foods is measured as salt in g/100g of total product weight, assessed through scanning of purchased product bar-codes and linking to a food and nutrient information database during a baseline period of two weeks before the intervention and over the intervention period |
| Completion date | 05/07/2019 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | All |
| Target sample size at registration | 40 |
| Total final enrolment | 50 |
| Key inclusion criteria | Current inclusion criteria as of 15/02/2019: 1. Participants’ most recent systolic blood pressure reading in the past 2 years is above 130 mmHg if they are currently taking anti-hypertensive medication or above 140 mmHg (if non-medicated) 2. If on pharmacological treatment for hypertension, participant has been prescribed a stable dose for at least the past 6 weeks. 3. Participant is willing and able to give informed consent for participation in the study 4. Male or female, aged between 18 and 80 years 5. English speaking 6. Who regularly shop in a supermarket (excluding online supermarkets), spending at least £25 at least once a fortnight 7. Own a smartphone (android or iOS) and express interest in using an app for healthy eating 8. Who express a desire for support to improve the nutritional quality of their diet to reduce their CVD risk Previous inclusion criteria: 1. Participants’ most recent blood pressure reading in the past 2 years is 140/90 mmHg or higher (taken in clinic, with or without subsequent ambulatory blood pressure monitoring daytime average or home blood pressure monitoring average blood pressure of 135/85 mmHg or higher) 2. Not currently taking hypertension medication 3. Participant is willing and able to give informed consent for participation in the study 4. Male or Female, aged between 18 and 80 years 5. English speaking 6. Who regularly shop in a supermarket (excluding online supermarkets), spending at least £25 at least once a fortnight 7. Own a smartphone (android or iOS) 8. Who express a desire for support to improve the nutritional quality of their diet to reduce their CVD risk |
| Key exclusion criteria | Current exclusion criteria as of 15/02/2019: 1. Already on a clinician supervised diet or a restricted diet 2. Unwilling to make dietary changes 3. Are currently using or have used the Foodswitch or Saltswitch apps previously 4. Unable to read and understand the instructions provided in English 5. Participants with secondary, previous accelerated or malignant hypertension as defined by read code 6. Currently being assessed for diagnosis of hypertension 7. Currently on any medication that may lead to hyponatraemia or fluid retention 8. Existing or recent cardiovascular conditions: heart attack or stroke within the last 3 months, heart failure of grade II New York Heart Association and more severe, or prolonged QT syndrome, angina, arrhythmia or atrial fibrillation 9. Currently participating in another study 10. Patients that the GP judges not able to meet the demands of the study or unlikely to comply with study procedures as stated in the protocol 11. They are planning on going away from home for more than 2 consecutive weeks during the 6 week intervention period Previous exclusion criteria: 1. Already on a clinician supervised diet or a restricted diet 2. Unwilling to make dietary changes 3. Are currently using or have used the Foodswitch or Saltswitch apps previously 4. Unable to read and understand the instructions provided in English 5. Currently on blood pressure lowering medication 6. Currently on any medication that may lead to hyponatraemia or fluid retention 7. Existing or recent cardiovascular conditions: heart attack or stroke within the last 3 months, heart failure of grade II New York Heart Association and more severe, or prolonged QT syndrome, angina, arrhythmia or atrial fibrillation. 8. Currently participating in another study (including follow-up) 9. Patients that the GP judges not able to meet the demands of the study or unlikely to comply with study procedures as stated in the protocol 10. They are planning on going away from home (holiday or other) for more than 4 consecutive days during the 6 week intervention period |
| Date of first enrolment | 20/09/2018 |
| Date of final enrolment | 01/05/2019 |
Locations
Countries of recruitment
- United Kingdom
- England
Study participating centre
Radcliffe Observatory Quarter
Woodstock Road
Oxford
OX2 6GG
United Kingdom
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Stored in repository |
| IPD sharing plan | The data will be in a non-publically available repository (University of Oxford). |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Results article | 21/10/2021 | 25/02/2022 | Yes | No | |
| Protocol article | protocol | 11/10/2019 | 14/10/2019 | Yes | No |
| HRA research summary | 28/06/2023 | No | No | ||
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
25/02/2022: Publication reference added.
07/09/2021: The following changes were made to the trial record:
1. The contact email was updated.
2. The plain English summary was updated to reflect these changes.
17/03/2021: The intention to publish date has been changed from 31/08/2020 to 17/04/2021.
11/06/2020: The intention to publish date has been changed from 31/12/2019 to 31/08/2020.
14/10/2019: Publication reference added.
12/06/2019: The total final enrolment was added.
08/05/2019: The recruitment end date was changed from 26/04/2019 to 01/05/2019.
26/03/2019: The condition has been changed from "Specialty: Primary Care, Primary sub-specialty: Cardiovascular disease; UKCRC code/ Disease: Cardiovascular/ Hypertensive diseases" to "Hypertension" following a request from the NIHR.
15/02/2019: The following changes were made:
1. The inclusion and exclusion criteria were updated.
2. The recruitment start date was changed from 30/05/2018 to 20/09/2018.
3. The recruitment end date was changed from 18/02/2019 to 26/04/2019.
4. The overall trial end date was changed from 30/04/2019 to 05/07/2019.
15/11/2018: The following changes were made:
1. The recruitment end date was changed from 30/10/2018 to 18/02/2019.
2. The overall trial end date was changed from 30/03/2019 to 30/04/2019.
3. The intention to publish date was changed from 30/09/2019 to 31/12/2019.
22/01/18: The following changes were made:
1. Recruitment start date was changed from 04/09/2017 to 30/05/2018.
2. Recruitment end date was changed from 04/12/2017 to 30/10/2018.
3. Overall trial end date was changed from 04/05/2018 to 30/03/2019.
4. Intention to publish date was changed from 04/05/2019 to 30/09/2019.
11/05/2017: Internal review.
