Whether or not this research shows that screening is effective and cost effective, it will be a landmark trial that will affect UK screening guidance and guidance elsewhere around the world.
- Professor Richard Hobbs, University of Oxford
Oxford University researchers are part of a collaboration of several universities chosen to lead a new £3m programme of research investigating screening to detect undiagnosed atrial fibrillation, a heart condition responsible for one in ten strokes.
Funded by National Institute for Health Research, the research will include the largest ever randomised controlled trial to find out whether screening for atrial fibrillation in people aged 65 and over can prevent stroke and other problems that cause early deaths like heart attacks. The project will also find out whether this approach represents good value for money for the NHS.
Atrial fibrillation is the most common disturbance of the heart rhythm, characterised by an irregular pulse. It affects up to 10 in 100 people over the age of 65, a considerable proportion of whom do not know they have the condition.
Atrial fibrillation may not be associated with any symptoms, but is linked to increased risk of stroke, heart attack, dementia and premature death. About 10% of strokes happen in people unaware that they have atrial fibrillation. However, therapy with medication (anticoagulation) is highly effective at reducing the risk.
At present, some GPs look for atrial fibrillation opportunistically by using a diagnostic device such as a hand-held electrocardiogram (ECG) or simply take the pulse of patients who could be visiting for any reason. However, this is not done in a systematic way, and only in some general practices.
The research will discover whether screening systematically for atrial fibrillation and offering optimal
treatment reduces the incidence of stroke, premature death and other health risks associated with atrial fibrillation.
Led by the University of Cambridge in collaboration with Oxford University's Primary Care Clinical Trials Unit, the trial will involve 120,000 patients aged over 65 in 300 general practices across England. Patients in 100 practices will undergo screening, and those in 200 practices will not. People who are found to have atrial fibrillation by the screening programme will be offered treatment with anticoagulant drugs to reduce their risk of stroke and heart attack. Both sets of patients will be followed up for five years to see whether screening and treatment leads to fewer strokes, heart attacks and deaths.
The programme of research will include a cost effectiveness analysis to assess whether screening is a good use of NHS resources. Researchers will also observe what goes on in general practices when screening is carried out and interview staff and patients to explore issues around consent to screening and patient concerns.
Lead investigator Professor Jonathan Mant, Professor of Primary Care Research and Head of the Primary Care Unit at the University of Cambridge, said: “We know that a significant proportion of strokes occur in people with undiagnosed atrial fibrillation. Anticoagulation therapy is a very effective treatment that can reduce the risk of stroke by about 65%, so many of these strokes are preventable.
“At the moment, atrial fibrillation is detected haphazardly in some practices by opportunistic case finding. Our NIHR programme of research is testing a way of systematically screening everybody over 65 for atrial fibrillation. It’s more complete than the existing approach and simple, so won’t take up much doctor or nurse time.”
One problem with the current approach is that some people do not have atrial fibrillation all the time but go into and out of an irregular heart rhythm. In this new research, patients will be loaned a handheld ECG device, provided by Zenicor, to measure a (single lead) ECG twice a day at home for two weeks. “This novel technique, the first time home screening has been used on this scale in the NHS, will detect intermittent atrial fibrillation that otherwise would be missed in a one-off test at a GP appointment,” said Prof Mant.
Co-applicant Professor Richard Hobbs, Professor of Primary Care Health Sciences at the University of Oxford and Director of the NIHR School for Primary Care Research, said: “There’s currently not any evidence on whether systematic screening for atrial fibrillation works, so the National Screening Committee is not able to recommend it. Whether or not this research shows that screening is effective and cost effective, it will be a landmark trial that will affect UK screening guidance and guidance elsewhere around the world.
“We’ve been wanting to do a large trial of atrial fibrillation screening for more than 10 years, and we’re now able to do so thanks to funding from the NIHR. It simply would not be possible to do such huge studies without significant investment such as from the NIHR.”
The UK National Screening Committee has welcomed this trial of systematic population screening for atrial fibrillation. Prof Robert Steele, Independent Chair of the UK National Screening Committee, and Prof Anne Mackie, Director of Screening at Public Health England, said: “Screening for atrial fibrillation, which is a major cause of morbidity and death, would seem to be an excellent idea, but it is only by robust research coupled with economic analysis can we be sure that the benefit of screening outweighs any harm that it may cause and that it is cost effective.”