Genetic testing of healthy people a ‘looming disaster’ says global health evidence expert

November 16, 2017

Professor Paul Glasziou, the Australian-based global authority on evidence in healthcare, today called for action to stem a growing tide of overtesting, overdiagnosis and overtreatment, saying ‘classifying people as diseased when they don’t have anything that would ever cause them a problem, is a growing problem in medicine.’

In an interview with the The Recommended Dose podcast, Professor Glasziou warned that the new wave of genetic testing could be a ‘looming disaster’ and that ‘the world is very unprepared for this’.

Professor Glasziou is director of the Centre for Research in Evidence-Based Practice at Bond University on the Gold Coast, where he is also a regular surfer.

‘There are some things where genetic tests will help – the BRCA1 breast cancer gene is one example, because it’s a very strong predictor,’ Professor Glasziou told The Recommended Dose, which is funded by Cochrane Australia. ‘But I think our problem is going to be that we will end up with lots of pretty weak predictors, and that means everyone will have this slightly elevated risk and we don’t know how to deal with the labelling that that entails… and that slightly increased risk in everybody.’

‘So I feel like the world is very unprepared for this at the moment, but it’s a looming disaster for medicine if we start doing lots of genetic testing we discover that you’ve got raised risk for 50 out of the 5000 diseases and you don’t actually know what to do with all that information except worry about it.’

Professor Glasziou acknowledges that for many the issue of overdiagnosis and overtesting can be difficult to accept given the prevailing doctrine in medicine for generations has been that early detection is the best medicine. ‘For everyone it’s intuitive that early detection should be better – that more information should always be better – but I the overdiagnosis pattern teaches us that earlier isn’t better.’

He also says there’s a growing global awareness of this critical issue and that health professionals from all of the disease areas, consumer groups, government bodies and groups like the Australian Cancer Councils that this is a real issue and something must be done to recognise and address the issues of overdiagnosis, overtesting and overtreatment.

Professor Glasziou nominates winding back the number of tests, changing our definition of diseases and increasing shared decision making as important steps to containing the problem- as well as finding doctors who are interested in evidence. And he cautions that we must accept a degree of uncertainty in health care.

‘We have to live with a degree of uncertainty… it’s that seeking to resolve all uncertainty that leads us I think to leads us to the overtesting and the overdiagnosis. We feel like we must be able to find an answer if we just do all the imaging and all the blood tests possible and what you’ll end up with is a lot of false positives that will lead you down the wrong path’.

The Podcast host is the globally respected researcher and journalist Dr Ray Moynihan, a senior research fellow at Bond University.

Listen to the full interview on The Recommended Dose - now available on SoundCloud and Stitcher. Available on iTunes from Thursday 16 November.

You can also hear The BMJ's Editor-in-Chief Fiona Godlee and leading US psychiatrist Allen Frances in conversation with Ray on episodes one and two, talking respectively about the need for much greater independence between doctors and drug companies and the increasing overdiagnosis of everyday life experiences and emotions as mental health conditions.