Early screening for dementia leads to overdiagnosis

The drive to diagnose dementia early by looking for minor changes in memory may be resulting in serious levels of overdiagnosis and inappropriate treatment, specialists from the University of Sydney and the UK report.

The screening of older people for minor memory changes - often called mild cognitive impairment or pre-dementia - is leading to unnecessary investigation and potentially harmful treatment for what is arguably an inevitable consequence of ageing.

The team of specialists say that expanding diagnosis of dementia will result in up to 65% of people aged over 80 having Alzheimer’s disease diagnosed - and up to 23% of non-demented older people being labelled with dementia.

They argue that this policy is not backed by evidence and ignores the risks, harms and costs to individuals, families and societies. It may also divert resources that are badly needed for the care of people with advanced dementia.

Paper co-author Professor David Le Couteur from Sydney University’s Charles Perkins Centre said dementia is an age-related condition and, with an ageing global population, it is predicted to become an overwhelming and costly problem.

“Although evidence suggests that five to 10% of people with mild cognitive symptoms will develop dementia each year, current policy in many countries is aimed at encouraging more widespread and earlier diagnosis of dementia,” he said.

“For example, in the US, the Medicare insurance program will cover an annual wellness visit to a physician that includes a cognitive impairment test. In England, the government has announced that it will reward general practitioners for assessing brain function in older patients - and has committed to have “a memory clinic in every town and every city” despite no sound evidence of benefit.

Le Couteur also said that imaging techniques and tests have been developed and are increasingly being used in diagnosing memory changes despite uncertainty about their accuracy.

“Furthermore, there are no drugs that prevent the progression of dementia or are effective in patients with mild cognitive impairment, raising concerns that once patients are labelled with disease or pre-disease, they may try untested therapies and run the risk of adverse effects.”

The paper co-authors also question whether ageing of the population is becoming a ‘commercial opportunity’ for developing screening, early diagnosis tests and medicines marketed to maintain cognition in old age.

The desire of politicians, dementia organisations, academics and clinicians in the field to raise the profile of dementia is understandable, write the authors, “but we risk being conscripted into an unwanted war against dementia”.

They suggest that the political rhetoric expended on preventing the burden of dementia would be much better served by efforts to reduce smoking and obesity, given the link that has been established between mid-life obesity and cigarettes with the risk of dementia.

Experts from around the world will gather at the upcoming Preventing Overdiagnosis conference to discuss how to tackle the threat to health and the waste of money caused by unnecessary care.

This work was published in the British Medical Journal.