Condition category
Circulatory System
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
High blood pressure (hypertension) is the largest contributor to global mortality and a major risk factor for heart disease and stroke. About 30% of the UK population suffer from hypertension.
A direct association has been found between survival and adherence to medication for high blood pressure (statin therapy). However, medication adherence is a significant problem with around 50% of patients with cardiovascular disease or its major risk factors not regularly taking their medications (adherence) one year after starting treatment.

The aim of this research is to assess adherence to anti-hypertensive and statin medication in a UK population through direct (urine testing) and self-report measures. These results can be combined with data from a survey we have designed and validated, to identify psychological barriers and facilitators to adherence. The findings will inform the design and deployment of new interventions based on behavioural science to improve adherence and thus patient outcomes.

Who can participate?
Patients at the GP surgery who are taking statins, or medication for high blood pressure

What does the study involve?
Taking part in the study will involve providing a small amount of personal information, most of which is collected routinely by the doctor. Participants will be asked to give a routine urine sample to check if the medicines prescribed are having the expected effect. Finally, participants will complete a simple questionnaire which will ask about experiences of taking blood pressure medications or statins and reasons why this may be difficult or easy. This will take approximately 20 minutes to complete. If necessary, medical notes may be accessed by members of the research team to check certain details.

What are the possible benefits and risks of participating?
There are no direct benefits bu the study will allow us to design ways to help people to take their medications and improve their blood pressure or cholesterol control in the future.
Taking part in the study involves providing a minimal amount of personal information, giving a routine urine sample and answering a simple questionnaire. There is no reasonable expectation that any harm will arise from this.

Where is the study run from?
Imperial College Healthcare NHS Trust, UK

When is the study starting and how long is it expected to run for?
April 2016 to June 2021

Who is funding the study?
1. Robert Luff Foundation, UK
2. NIHR Imperial Patient Safety Translational Research Centre, UK

Who is the main contact?
Dr Gaby Judah

Trial website

Contact information



Primary contact

Dr Gaby Judah


Contact details

Imperial College London
10th Floor
QEQM Building
St Mary's Hospital
Praed Street
W2 1NY
United Kingdom
+44 (0)203 3121962



Additional contact

Prof Peter Server


Contact details

Imperial College London - Hammersmith Campus
Imperial College Translational and Experimental Medicine Building (ICTEM)
National Heart and Lung Institute (NHLI)
Du Cane Road
W12 0NN
United Kingdom
+44 (0)207 594 1099



Additional contact

Dr David Wingfield


Contact details

Brook Green Medical Centre
Bute Gardens
W6 7EG
United Kingdom
+44 (0)207 471 3333

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number

38504, IRAS 200751

Study information

Scientific title

Understanding the psychological determinants of medication adherence in patients taking anti-hypertensive and statin medication in the United Kingdom


Study hypothesis

Research questions:
- What is the self-reported and objectively measured rate of anti-hypertensive and statin medication non-adherence in a UK patient population?
- What are the psychological and behavioural barriers to medication adherence?
- What are the psychological and behavioural facilitators of medication adherence?
- Can identified behavioural and psychological constructs be used to predict medication non-adherence?

Ethics approval

Approved 10/03/2016, East Midlands - Derby Research Ethics Committee (The Old Chapel, Royal Standard Place, Nottingham, NG1 6FS; +44(0)207 104 8036;, ref: 16/EM/0106

Study design

Observational; Design type: Cross-sectional

Primary study design


Secondary study design

Cross sectional study

Trial setting


Trial type


Patient information sheet

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




The research project takes place in three distinct but linked phases - each of which will be conducted at a different time sequentially and involve a different cohort of patients from the study population.

1) Semi-structured interviews - formalised semi-structured interviews of patients attending the Peart Rose clinic will be performed. Whilst the focus will be on allowing patients to freely express their experience of taking medication, a structured topic guide will be used to direct the interviews as required to help elicit barriers and facilitators of adherence. Patients will be recruited until saturation (<10% statement duplication), which from previous similar studies is likely to be approximately 15 patients. The interviews will be analysed thematically to guide questionnaire item generation in conjunction with an appropriate literature review. Each interview will take approximately 20 mins.

2) Questionnaire design and piloting - following thematic analysis of the semi-structured interviews and a thorough systematic literature review questionnaire items will be generated and constructively aligned to the validated Health Belief Model and Theoretical Domains Framework of behaviour. The pilot questionnaire will then be tested on a sample patient population of 30 patients and subsequently refined via calculation of ceiling and floor effects, inter-item correlation and Cronbach’s Alpha internal consistency measures. The pilot questionnaire items will also be assessed for readability and comprehensibility using a validated method to ensure it is appropriate for the target
population. Completion of the pilot questionnaire will take approximately 15 minutes and recruitment of participants will be from the same population and via the same methodology as will be adopted with the final definitive questionnaire study.

3) Principal data collection and testing - in order to validate the new questionnaire, and to assess the association between medication adherence and its’ behavioural and psychological determinants approximately 200 patients from the Peart Rose Hypertension Clinic will be recruited into a cross-sectional evaluative study. During routine clinic attendance participants will complete the questionnaire. In addition routine demographic information including age, sex, martial status, co-morbidities, medication history and socio-economic metrics will be collected. Participants will also be asked to complete validated measures of self-reported medication adherence (Moresby Medication Adherence Scale (MMAS-8), and the Self-Report Behavioural Automaticity Index (SRBAI)) in order to aid in the validation of the new questionnaire. Patients give urine samples on a regular basis as part of their routine care in the clinic; results of direct measures of medication adherence will be collected and utilised to validate the questionnaire.

All results will then be assimilated and appropriately analysed prior to publication and dissemination - hopefully providing a new validated questionnaire for assessing medication adherence in a UK secondary care hypertensive population, together with providing evidence for development of a short assessment tool and further studies in other patient populations e.g. General Practice.

Intervention type



Drug names

Primary outcome measure

Measured during the data collection session:
1. Urine test of medication adherence. A urine sample will be tested for anti-hypertension and statin metabolites to give a valid and reliable direct measure of medication adherence within the past 24hrs.
2. Self-reported medication adherence. Using 3 item Likert scale from Voils 2012

Secondary outcome measures

Measured during the data collection session:
1. Habit, measured using the Self Report Automaticity Index, a 4-item Likert scale from Gardner 2012

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

All patients attending a primary or secondary care service for the treatment of hypertension that are willing to take part

Participant type


Age group




Target number of participants

Planned Sample Size: 450; UK Sample Size: 450

Participant exclusion criteria

In the opinion of the investigator unsuitable or unable to adequately complete questionnaire e.g. due to inadequate level of English comprehension

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

St. Mary's Hosptial
Imperial College Healthcare NHS Trust Praed Street
W2 1NY
United Kingdom

Sponsor information


Imperial College London

Sponsor details

Research Governance Office
Room 221
Level 2
Medical School Building
Norfolk Place
W2 1PG
United Kingdom
+44 (0)207 5941862

Sponsor type




Funder type


Funder name

Robert Luff Foundation

Alternative name(s)

Funding Body Type

private sector organisation

Funding Body Subtype

Trusts, charities, foundations (both publically funded and privately funded)


United Kingdom

Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Funder name

Imperial College London

Alternative name(s)

Funding Body Type

private sector organisation

Funding Body Subtype

Universities (academic only)


United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication in a high-impact peer-reviewed journal.

IPD sharing statement:
The current data sharing plans for this study are unknown and will be 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

14/01/2020: Uploaded protocol Version 1.7, 6 August 2019 (not peer reviewed). 09/12/2019: Trial’s existence confirmed by National Institute for Health Research (NIHR).