Blood pressure measurement for cardiovascular risk prediction

Aims:

Doctors regularly estimate how likely it is that a patient will have a heart attack or stroke in the near future, using information about the patient’s health. We aim to find out if measuring blood pressure in different ways changes the estimates doctors make and whether this changes how they treat their patients.

Why this is important:

Blood pressure can be measured in several different settings e.g. at a doctors surgery or at home. For some people, their blood pressure readings will change depending on where the measurement is taken. For example, many people have an alerting reaction when their blood pressure is measured by their doctor, so their readings are higher at the doctor’s surgery compared to those taken at home.

Doctors often estimate about how likely it is that a patient will have a heart attack of stroke. We hope to find ways to make this more accurate, allowing treatment to be targeted to where its needed most." - Professor Richard McManus, University of Oxford.

Doctors often use risk calculators to estimate how likely it is that a patient will have a heart attack or stroke in the near future so that they can advise on treatment or lifestyle changes for those who are at particularly high risk. Primarily, these calculators are intended for use with blood pressure measurements taken in the doctor’s surgery and so using measurements taken elsewhere may not be appropriate. We aim to find out how much estimates of risk change in individual patients, when blood pressure measured in different ways is used in these calculators. We also aim to find out how many people may have their treatment changed based on these differences.

Recent research also suggests that variation in blood pressure as well as the average blood pressure level may be important in determining how likely a heart attack or stroke is. We also aim to develop a new calculator that will additionally account for variation in blood pressure as well as more traditional patient characteristics.

Methods:

1. Review of the risk calculators doctors currently use.
2. Systematic review of research regarding blood pressure variability and risk of heart attack/ stroke.
3. Online patient survey to find out how doctors measure blood pressure as part of usual care.
4. Secondary analysis of data from two blood pressure studies to determine the effect of different blood pressure measurement on risk estimates.
5. Development of a new risk calculator using electronic medical records from the clinical practice research datalink.

How this could benefit patients:

This project will support doctors in deciding who is at high risk of a heart attack or stroke. This will help to target treatment and advice at patients with the greatest need. It will also mean that fewer patients are unnecessarily prescribed treatments which they must continue to take throughout their life.