DNA tests might identify ‘invisible population’ who are not currently seen as in danger

Hundreds of thousands more adults in the UK could benefit from taking statins because their genes put them at high risk of heart disease, research suggests.

Speaking on Wednesday at the UK Biobank conference in London, Prof Sir Peter Donnelly, the founder of the company Genomics Plc, warned of an “invisible population” who are not identified as at risk by current screening programmes because their blood pressure and cholesterol do not raise red flags.

“There are a lot of people who aren’t on the radar, who wouldn’t have been offered statins, but who are at high risk when you include genetics,” he said.

Donnelly, who was previously the director of the Wellcome Centre for Human Genetics, is pioneering a new kind of predictive DNA test, which measures the contributions of thousands of genes. Earlier this year, the health secretary, Matt Hancock, called for these kind of tests, which can assess risk for common cancers and heart disease, to be rolled out on the NHS without delay.

The latest work suggests heart disease risk genes can work independently from known risk factors, including high blood pressure and cholesterol, which are used by GPs to decide whether someone would benefit from taking medicines such as statins.

This means that if a DNA test was incorporated into national screening, as Hancock has proposed, there would be a substantial shakeup of who is classified as “high risk”, which is a 10% chance of heart disease in the next 10 years.

Donnelly’s research suggests that for every 1 million adults aged 40 to 55 who are identified as being at high risk of heart disease, if a genetic risk score was also included about a quarter of these individuals could be shifted into the low-risk category. This is because even though their cholesterol and blood pressure might be higher than average, they carry protective genes that make a heart attack or stroke far less likely.

However, the genetic test would also move 528,000 adults who would previously have been missed into the high-risk category, because of their genetic profiles. Currently about 4 million people are being treated with statins in England.

“You end up with more people above the risk threshold, but they’re not the same people,” said Donnelly. “Many of these high-risk individuals are currently invisible to the health system.

“Our focus now is on how to incorporate genetic scores for heart disease into the NHS in ways which are equitable, and which help, rather than further complicate, work for already overstretched GP practices.”

Further work is required to establish whether this hidden population would benefit from statins, which work by lowering cholesterol, to the same degree as those with high cholesterol. However, a previous study indicates those with risky genetic profiles get the greatest benefits from preventative medication.

Tim Chico, a professor of cardiovascular medicine at the University of Sheffield, said genetic scores were very likely to play a role in the management of heart health in the next decade. While statins play a crucial role, Chico said, there should also be a focus by doctors on the social and environmental contributors to heart disease, including diet and exercise.





