Fact check: Health Minister Peter Dutton’s dementia facts flawed

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Fact check: Health Minister Peter Dutton’s dementia facts flawed

The number of people being diagnosed with dementia is going to soar to 7,500 a week, Health Minister Peter Dutton says.

Mr Dutton argues the Government’s controversial Medicare reforms announced in the budget are necessary to ensure the health system can provide for genomic testing, new cancer drugs and the growing number of people being diagnosed with dementia.

He told ABC’s Lateline on September 8, Australia needs to be able to pay for “the fact that 170 people per week today are being diagnosed with dementia, but in a number of years it’ll be 7,500 a week”.

It’s well recognised that the number of people with dementia is growing, but could the number being diagnosed really increase fortyfold in a number of years?

ABC Fact Check takes a look at the numbers.

Prevalence: The number of people with dementia

Dementia is a term used to describe over 100 different conditions which cause a progressive decline in a person’s functioning. A loss of memory, intellect, and rationality are often experienced by dementia sufferers.

Advocacy group Alzheimer’s Australia says there are over 330,000 Australians living with dementia. But this is only an estimate. There has never been a national study in Australia of dementia prevalence using clinical diagnoses, according to advisory firm Deloitte Access Economics in a September 2011 report.

In the absence of clinical data, a number of studies have estimated dementia prevalence in Australia. Some have based their estimates on diagnosis rates in Europe. Others have attempted to evaluate rates based on large Australian datasets containing mini-mental state examinations, a brief questionnaire used to screen for cognitive impairment. 

The Deloitte report says: “It is estimated there are 266,574 people with dementia in Australia in 2011, projected to increase to 553,285 people by 2030, and 942,624 people by 2050.”

Based on these estimates, by 2050 there would be 3.5 times more people with dementia than in 2011.

The Australian Institute of Health and Welfare estimates 298,000 Australians were living with dementia in 2011 – more than 10 per cent higher than the Deloitte figure. The institute projects the number will triple to 900,000 by 2050.

International studies show similar trends. A 2013 publication by Alzheimer’s Disease International estimates the global number of dementia sufferers will increase threefold – from 36 million in 2010 to 115 million by 2050. It says an ageing population is the main driver of projected increases.

The Australian Bureau of Statistics provides an estimate of dementia prevalence within Australia, however the Deloitte report says “it relies on self-reported identification, leading to severe under reporting due to an individual’s limited capacity to recognise mild and moderate dementia if not formally diagnosed”. The ABS predicts of all people over 65 years of age, 2.7 per cent had dementia or Alzheimer’s disease.

But prevalence studies do not estimate how many new cases are being diagnosed each week, as per Mr Dutton’s claim.

Incidence: The number of new cases

The 2011 Deloitte report said there was little data relating to the number of newly diagnosed cases, or incidence, of dementia. “In general, there are problems with diagnosing dementia, as the date of onset is generally undetermined due to the progressive onset of the condition,” it said.

Professor Henry Brodaty, co-director of the Centre for Healthy Brain Ageing at the University of NSW, tells Fact Check there has never been an incidence study of dementia in Australia.

An incidence study involves reviewing a sample of healthy people who are then revisited years later to see how many have developed a medical condition, like dementia, Professor Brodaty explained.

Some estimates of incidence rates for dementia do exist in Australia, but a 2007 report by the Australian Institute of Health and Welfare says: “The methodological issues associated with determining estimates of dementia incidence – that is, the number of new cases in a specified period – mean that there are few data sources available in this area.”

In its more recent report, the institute used old data to estimate that 173 Australians joined the group of people with dementia each day in 2011. That’s around 1,211 new cases a week.

However, the report said: “Methodological challenges in estimating the incidence of dementia include a lack of relevant data, for example, on duration of illness and relative risk of mortality.”

It went on to say that because of “the lack of new data sources on the incidence of dementia, producing revised incidence estimates is beyond the scope of this report”.

The 2011 Deloitte report echoed the sentiment that estimating how many people were diagnosed with dementia each week was fraught with difficulty.

It said while some Australian studies have used information from health studies undertaken in Europe, this is “not ideal as the data used in these studies are relatively old (from the mid 1980s to the mid 1990s) and imply that Australia has the same dementia incidence and prevalence rates as Europe”.

“This is despite known differences in dementia risk factors,” it said.

Expert estimates

Professor Brodaty says the most simple way to estimate incidence is by using mortality rates in the following equation.

Assuming that a person with a dementia diagnosis would live on average for five years, the number of new cases would be one fifth of the prevalence figure.

Based on the Alzheimer’s Australia prevalence figure of 330,000, this would result in 66,000 new cases each year, or over 1,260 per week.

If the average person diagnosed with dementia had a 10-year life span, then the figures would halve. Likewise, Professor Brodaty said if the lifespan was only three years the figures would go up.

In terms of predicting the cases into the future, Professor Brodaty says it’s widely agreed that cases will triple over the next 40 years – or by 2050 – so by that stage there would be around 3,600 cases per week.

Peter Dutton’s numbers

Before the September 2013 federal election, the Coalition released a policy to ‘boost dementia research’, which says: “There are over 320,000 Australians living with dementia and every week 1,700 new cases are added to this total. Alarmingly, by 2050 nearly 7,500 Australian will be diagnosed with dementia every week.”

Mr Dutton’s claim that 170 people are diagnosed with dementia each week is significantly less than estimates given by Professor Brodaty or any of the reports consulted by Fact Check as well as what’s in the Coalition policy document.

An increase from 170 cases per week to 7,500 cases per week in “a number of years”, as Mr Dutton put it, amounts to a fortyfold increase. But the best estimates from reports around the globe suggest figures are set to treble over 40 years.

As for the 7,500 per week by 2050 mentioned in the Coalition’s policy document, Fact Check has been unable to verify this figure which appears to be on the high side when compared to other estimates.

If the generous weekly incidence figure of 1,700 per week is trebled, as per the expert estimates, it would be around 5,100 per week by 2050.

The verdict

Mr Dutton predicts a fortyfold increase in the number of dementia cases being diagnosed each week “in a number of years”. This is not supported by the evidence, which predicts cases will triple over the next four decades.

Even if he had cited the figures in the Coalition policy document, he would still be on shaky ground.

There has never been a clinical study of the rate of new cases of dementia diagnosed in Australia, and experts say estimating incidence reliably is difficult.

While rates of dementia are climbing, Mr Dutton’s figures aren’t “fact” as he said.

His claim is flawed.

Sources