PRedicting Out of OFfice Blood Pressure in the clinic (PROOF-BP)
Lead Research Organisation:
University of Oxford
Department Name: Primary Care Health Sciences
Abstract
Heart attacks and strokes are the main cause of death and disability in the developed world. Patients with high blood pressure (hypertension) are more likely to suffer a heart attack or stroke. The risk of this happening can be significantly reduced with drugs which lower blood pressure. Accurate measurement of blood pressure is therefore vital to ensure that patients with high blood pressure are recognised and treated appropriately.
New clinical guidelines recommend that blood pressure is measured for 24 hours to confirm patients with high blood pressure. Measuring blood pressure for 24 hours is obviously time consuming, but also expensive and often uncomfortable for patients. Despite this, it is recommended because it reduces the number of patients being incorrectly diagnosed with high blood pressure. Incorrect diagnoses occur because patients who are anxious when they visit the doctor's surgery often have high blood pressure which then decreases to normal levels when they return home. This is known as the white coat effect. These patients do not require treatment with blood pressure lowering drugs but may be prescribed them because the doctor doesn't realise that the reason their blood pressure is raised is because they are anxious. Incorrect prescription of these drugs may have bad consequences for the patient and is a waste of NHS money.
This project aims improve the accuracy of blood pressure measurement in the doctor's surgery and thus reduce the need for 24 hour measurements. Using a new blood pressure measurement technique, our pilot work suggests that it is possible to predict which patients have high blood pressure because they are anxious and which patients have true raised blood pressure requiring treatment. This new technique could identify which patients can be treated on the basis of blood pressure measurements made in the doctor's surgery and therefore reduce the number of patients needing to undergo expensive, uncomfortable, 24 hour measurement. It could therefore improve the quality of patient care and save money for the NHS.
The aim of this project is to establish how good this new technique is at predicting true blood pressure and whether it can be used on a day-to-day basis in the doctor's surgery. The effectiveness of this blood pressure measurement technique will be investigated using existing data collected from a typical population of patients in primary care. This analysis will establish the inputs required to develop a blood pressure measurement tool for use in the doctor's surgery. This tool will then be developed and tested it on patients from doctor's surgeries across Birmingham. The final stage of the project will involve comparing the performance of the new tool against the standard method of blood pressure measurement currently being used (patients with suspected high blood pressure being sent for 24 hour measurement) in the context of a clinical trial. Only the initial planning (pilot) for this clinical trial will be completed during this fellowship. Further funding will be sought to complete this clinical trial after the fellowship has concluded. The project will not involve the use of medicinal products (drugs) or human tissue.
The Fellow will conduct all analyses of existing datasets proposed in this project with the assistance of colleagues in the host institution. The development of a blood pressure measurement tool will be done with assistance from the IT programming team in the Primary Care Clinical Research and Trials Unit at the University of Birmingham.
New clinical guidelines recommend that blood pressure is measured for 24 hours to confirm patients with high blood pressure. Measuring blood pressure for 24 hours is obviously time consuming, but also expensive and often uncomfortable for patients. Despite this, it is recommended because it reduces the number of patients being incorrectly diagnosed with high blood pressure. Incorrect diagnoses occur because patients who are anxious when they visit the doctor's surgery often have high blood pressure which then decreases to normal levels when they return home. This is known as the white coat effect. These patients do not require treatment with blood pressure lowering drugs but may be prescribed them because the doctor doesn't realise that the reason their blood pressure is raised is because they are anxious. Incorrect prescription of these drugs may have bad consequences for the patient and is a waste of NHS money.
This project aims improve the accuracy of blood pressure measurement in the doctor's surgery and thus reduce the need for 24 hour measurements. Using a new blood pressure measurement technique, our pilot work suggests that it is possible to predict which patients have high blood pressure because they are anxious and which patients have true raised blood pressure requiring treatment. This new technique could identify which patients can be treated on the basis of blood pressure measurements made in the doctor's surgery and therefore reduce the number of patients needing to undergo expensive, uncomfortable, 24 hour measurement. It could therefore improve the quality of patient care and save money for the NHS.
The aim of this project is to establish how good this new technique is at predicting true blood pressure and whether it can be used on a day-to-day basis in the doctor's surgery. The effectiveness of this blood pressure measurement technique will be investigated using existing data collected from a typical population of patients in primary care. This analysis will establish the inputs required to develop a blood pressure measurement tool for use in the doctor's surgery. This tool will then be developed and tested it on patients from doctor's surgeries across Birmingham. The final stage of the project will involve comparing the performance of the new tool against the standard method of blood pressure measurement currently being used (patients with suspected high blood pressure being sent for 24 hour measurement) in the context of a clinical trial. Only the initial planning (pilot) for this clinical trial will be completed during this fellowship. Further funding will be sought to complete this clinical trial after the fellowship has concluded. The project will not involve the use of medicinal products (drugs) or human tissue.
The Fellow will conduct all analyses of existing datasets proposed in this project with the assistance of colleagues in the host institution. The development of a blood pressure measurement tool will be done with assistance from the IT programming team in the Primary Care Clinical Research and Trials Unit at the University of Birmingham.
Technical Summary
Background
Accurate blood pressure (BP) measurement is important to ensure antihypertensive treatment is targeted appropriately. New guidelines recommend the use of the 'gold standard' out of office measurement to confirm all diagnoses of hypertension. Our own pilot work suggests that the characteristics of BP measured repeatedly in the clinic can be used to predict out office BP thus, reducing the need for expensive out of office measurement. This method of assessing clinic BP characteristics has only been evaluated in patients with uncontrolled hypertension. Further work is needed to translate this novel method into routine clinical practice.
Aims
1)Establish the predictive abilities of multiple clinic BP measurements for out of office BP in a general population.
2)Develop a 'triaging' tool which reduces the number of patients with suspected hypertension being referred for out of office BP measurement.
3)Pilot a clinical trial assessing general practitioner (GP) use of this triaging tool for patients with suspected and existing hypertension.
Methods
Using a dataset of approximately 1,400 patients (>18 years; white, South Asian or Black ethnicity from within the UK and Canada), BP characteristics from multiple clinic measurements will be estimated using polynomial regression modelling. These will be compared to out of office BP monitoring (ambulatory and home) and the predictive abilities of clinic BP for white coat and masked hypertension will be evaluated. Using the resulting diagnostic thresholds for these conditions, a web based tool for use in clinical practice will be developed. This will be piloted in GP practices in Birmingham, providing preliminary data to inform a full clinical trial.
Scientific/Medical opportunities
This work presents an opportunity to improve the diagnosis of hypertension and accuracy of routine clinic BP measurement. This could lead to significant cost savings and improved quality of care for patients with hypertension.
Accurate blood pressure (BP) measurement is important to ensure antihypertensive treatment is targeted appropriately. New guidelines recommend the use of the 'gold standard' out of office measurement to confirm all diagnoses of hypertension. Our own pilot work suggests that the characteristics of BP measured repeatedly in the clinic can be used to predict out office BP thus, reducing the need for expensive out of office measurement. This method of assessing clinic BP characteristics has only been evaluated in patients with uncontrolled hypertension. Further work is needed to translate this novel method into routine clinical practice.
Aims
1)Establish the predictive abilities of multiple clinic BP measurements for out of office BP in a general population.
2)Develop a 'triaging' tool which reduces the number of patients with suspected hypertension being referred for out of office BP measurement.
3)Pilot a clinical trial assessing general practitioner (GP) use of this triaging tool for patients with suspected and existing hypertension.
Methods
Using a dataset of approximately 1,400 patients (>18 years; white, South Asian or Black ethnicity from within the UK and Canada), BP characteristics from multiple clinic measurements will be estimated using polynomial regression modelling. These will be compared to out of office BP monitoring (ambulatory and home) and the predictive abilities of clinic BP for white coat and masked hypertension will be evaluated. Using the resulting diagnostic thresholds for these conditions, a web based tool for use in clinical practice will be developed. This will be piloted in GP practices in Birmingham, providing preliminary data to inform a full clinical trial.
Scientific/Medical opportunities
This work presents an opportunity to improve the diagnosis of hypertension and accuracy of routine clinic BP measurement. This could lead to significant cost savings and improved quality of care for patients with hypertension.
Planned Impact
Cardiovascular disease is the leading cause of morbidity and mortality in the UK and around the world. The most significant, modifiable risk factor for cardiovascular disease is high blood pressure and in the UK, it affects up to one third of those aged 35 and over with the figure rising to 64-73% with increased age. Many more patients are thought to remain undiagnosed and untreated. This work specifically focuses on improving the care of patients with treated and undiagnosed hypertension. In those with a diagnosis of hypertension, treatment is dependent on accurate measurement of blood pressure in the clinic. Patients suffering white coat or masked hypertension may be over or under treated on the basis of this routine measurement. Patients with undiagnosed hypertension may have their blood pressure measured in the clinic but if they suffer from masked hypertension, under current practice they will not be sent for out of office measurement and therefore will not receive the treatment they need to control their blood pressure.
Predicting which patients suffer from white coat or masked hypertension will allow clinicians to target out of office blood pressure measurement to those who need it most. This will improve the accuracy of blood pressure measurement, thus reducing the proportion of patients with undiagnosed hypertension and increasing the number receiving the correct treatment for their condition. This work could therefore benefit patients with existing or suspected hypertension and also the clinicians tasked with managing their care.
By the end of this fellowship, I will have developed a tool which can be used in clinical practice and have laid the foundations for a definitive clinical trial which will establish the effectiveness and cost effectiveness of this tool in clinical practice. The necessary equipment needed to implement this novel method of blood pressure measurement already exists in general practices across the country. A recent survey suggested that at least half of blood pressure monitors in general practice are automatic and this figure is likely to rise now that the traditional mercury devices have been banned. It is likely that this methodology could easily be implemented once an evidence base has been established. There is the very real possibility that patients and clinicians could benefit directly from this research in the short term.
The primary research outcome of this fellowship will be to establish a sufficient evidence base to inform a clinical trial to establish the use of a new blood pressure measurement tool in routine clinical practice. Following this trial and the wide dissemination of its results, guideline development groups from the National Institute for Clinical Excellence and the British Hypertension Society will be engaged to ensure that this method blood pressure measurement (if proven to be effective) is incorporated into routine clinical practice. All patients who have their blood pressure measured accurately benefit from the correct treatment and reduced risk of cardiovascular disease. Therefore, this research has great potential to directly influence patient care.
Predicting which patients suffer from white coat or masked hypertension will allow clinicians to target out of office blood pressure measurement to those who need it most. This will improve the accuracy of blood pressure measurement, thus reducing the proportion of patients with undiagnosed hypertension and increasing the number receiving the correct treatment for their condition. This work could therefore benefit patients with existing or suspected hypertension and also the clinicians tasked with managing their care.
By the end of this fellowship, I will have developed a tool which can be used in clinical practice and have laid the foundations for a definitive clinical trial which will establish the effectiveness and cost effectiveness of this tool in clinical practice. The necessary equipment needed to implement this novel method of blood pressure measurement already exists in general practices across the country. A recent survey suggested that at least half of blood pressure monitors in general practice are automatic and this figure is likely to rise now that the traditional mercury devices have been banned. It is likely that this methodology could easily be implemented once an evidence base has been established. There is the very real possibility that patients and clinicians could benefit directly from this research in the short term.
The primary research outcome of this fellowship will be to establish a sufficient evidence base to inform a clinical trial to establish the use of a new blood pressure measurement tool in routine clinical practice. Following this trial and the wide dissemination of its results, guideline development groups from the National Institute for Clinical Excellence and the British Hypertension Society will be engaged to ensure that this method blood pressure measurement (if proven to be effective) is incorporated into routine clinical practice. All patients who have their blood pressure measured accurately benefit from the correct treatment and reduced risk of cardiovascular disease. Therefore, this research has great potential to directly influence patient care.
Publications
A'Court C
(2016)
Blood pressure measurement: a call to arms.
in The British journal of general practice : the journal of the Royal College of General Practitioners
Albasri A
(2018)
Hypertension referrals from community pharmacy to general practice: multivariate logistic regression analysis of 131 419 patients.
in The British journal of general practice : the journal of the Royal College of General Practitioners
Albasri A
(2017)
A comparison of blood pressure in community pharmacies with ambulatory, home and general practitioner office readings: systematic review and meta-analysis.
in Journal of hypertension
Monahan M
(2018)
Predicting Out-of-Office Blood Pressure in the Clinic for the Diagnosis of Hypertension in Primary Care: An Economic Evaluation.
in Hypertension (Dallas, Tex. : 1979)
Penaloza-Ramos MC
(2014)
Cost-effectiveness of optimizing acute stroke care services for thrombolysis.
in Stroke
Sheppard J
(2018)
Benefits and Harms of Antihypertensive Treatment in Low-Risk Patients With Mild Hypertension
in JAMA Internal Medicine
Sheppard JP
(2015)
Prognostic significance of the morning blood pressure surge in clinical practice: a systematic review.
in American journal of hypertension
Sheppard JP
(2016)
Prevalence and predictors of hospital prealerting in acute stroke: a mixed methods study.
in Emergency medicine journal : EMJ
Sheppard JP
(2016)
Predicting Out-of-Office Blood Pressure in the Clinic (PROOF-BP): Derivation and Validation of a Tool to Improve the Accuracy of Blood Pressure Measurement in Clinical Practice.
in Hypertension (Dallas, Tex. : 1979)
Description | NIHR CLAHRC Phase 2 Project Funding |
Amount | £379,051 (GBP) |
Organisation | National Institute for Health Research |
Department | NIHR CLAHRC Oxford |
Sector | Public |
Country | United Kingdom |
Start | 06/2016 |
End | 12/2018 |
Description | NIHR SPCR Funding Round 9 |
Amount | £17,148 (GBP) |
Organisation | National Institute for Health Research |
Department | School for Primary Care Research |
Sector | Academic/University |
Country | United Kingdom |
Start | 09/2015 |
End | 09/2016 |
Description | SPCR Funding round 10 |
Amount | £534,382 (GBP) |
Funding ID | 335 |
Organisation | National Institute for Health Research |
Department | School for Primary Care Research |
Sector | Academic/University |
Country | United Kingdom |
Start | 09/2016 |
End | 05/2019 |
Title | PROOF-BP tool |
Description | The PROOF-BP tool is a clinical prediction tool which uses routinely available information about a patient's characteristics and medical history to predict what their blood pressure level would be if it were to be measure in an out-of-office setting (via ambulatory or self-monitoring). |
Type Of Material | Model of mechanisms or symptoms - human |
Year Produced | 2016 |
Provided To Others? | Yes |
Impact | The PROOF-BP tool is currently being examined for its accuracy in routine clinical practice. Further assessments of its cost-effectiveness are also under way. This findings of this follow-up work could lead to the adoption of its use in routine clinical practice. |
URL | https://sentry.phc.ox.ac.uk/proof-bp/ |
Title | PROOF-ABPM |
Description | The Prospective Register Of patients undergoing repeated OFfice and Ambulatory Blood Pressure Monitoring (PROOF-ABPM) is a database of patient characteristics, repeated clinic and ambulatory blood pressure, clinical assessment data linked to subsequent admissions to hospital and mortality. The PROOF-ABPM is unique in its consideration of multiple clinic blood pressure measurements in relation to ambulatory blood pressure readings taken in routine clinical practice. |
Type Of Material | Database/Collection of data |
Provided To Others? | No |
Impact | Recruitment of patients to the database is ongoing. Notable impact arising from the database is not expected before 2017. |
URL | http://www.phctrials.ox.ac.uk/studies/proof-abpm |
Description | Clark Collaboration - University of Exeter |
Organisation | University of Exeter |
Department | Medical School |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Data analysis |
Collaborator Contribution | Data sharing |
Impact | No outputs to date |
Start Year | 2015 |
Description | Columbia collaboration |
Organisation | Columbia University |
Country | United States |
Sector | Academic/University |
PI Contribution | Collaboration with a consortium of researchers across the US, lead by investigators at Columbia University, New York. The aim of this work is to collate datasets and externally validate the PROOF-BP algorithm in a US population. We have provided expertise on how to implement the tool in these data and conduct the analyses |
Collaborator Contribution | They have collated datasets to validate the tool and will be responsible for conducting the analyses. |
Impact | n/a |
Start Year | 2019 |
Description | Godwin Collaboration - Memorial University of Newfoundland |
Organisation | Memorial University of Newfoundland |
Country | Canada |
Sector | Academic/University |
PI Contribution | This collaboration involves pooling of existing datasets to allow new analyses which I will conduct as part of my MRC fellowship |
Collaborator Contribution | Contributed ~250 patients for data analyses |
Impact | Papers published relating to the development and validation of the PROOF-BP tool |
Start Year | 2013 |
Description | Mckinstry Collaboration - University of Edinburgh |
Organisation | University of Edinburgh |
Department | Centre for Population Health Sciences |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | This collaboration involves pooling of existing datasets to allow new analyses which I will conduct as part of my MRC fellowship |
Collaborator Contribution | Provided data on 400+ patients for analysis |
Impact | Papers published relating to the development and validation of the PROOF-BP tool |
Start Year | 2013 |
Description | Myers Collaboration - Sunnybrook Health Sciences Centre |
Organisation | Sunnybrook Health Sciences Centre |
Country | Canada |
Sector | Academic/University |
PI Contribution | This collaboration involves pooling of existing datasets to allow new analyses which I will conduct as part of my MRC fellowship |
Collaborator Contribution | Contributed ~250 patients for data analyses |
Impact | Papers published relating to the development and validation of the PROOF-BP tool |
Start Year | 2013 |
Description | Article for The Conversation |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | The purpose of this activity was to explain the general principles of my research area to the general public. To achieve this, I wrote an article for the online newspaper 'The Conversation' entitled, "Why we should measure our own blood pressure", which explains how blood pressure is measured and how misdiagnosis and management can occur - a key rationale for my MRC fellowship work. The article was published online and read by 1,875 people in the first 10 days. |
Year(s) Of Engagement Activity | 2016 |
URL | https://theconversation.com/why-we-should-measure-our-own-blood-pressure-53928 |
Description | PROOF- BP paper publication |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Interviews for newspaper and radio |
Year(s) Of Engagement Activity | 2016 |
URL | https://www.theguardian.com/society/shortcuts/2016/mar/22/hidden-high-blood-pressure-white-coat-synd... |
Description | RECEPTS press release |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Media (as a channel to the public) |
Results and Impact | In conjunction with the publication of our article on receptionist's ability to recognised and respond to patients calling their GP with symptoms of stroke (the RECEPTS study), a press release was sent out. This was reported in the national print media (including the Daily Mail) and via various sources online (including NHS Choices 'Behind the headlines', Pulse magazine and the National Health Executive). |
Year(s) Of Engagement Activity | 2015 |
URL | http://www.dailymail.co.uk/news/article-3142677/Many-stroke-victims-saved-GP-receptionists-Patients-... |