Familial hypercholesterolaemia may be twice as common in Australia as first thought, and has emerged as a “major public health problem”, new evidence suggests.
And a narrative review published online this week by the Medical Journal of Australia says childhood may be the best time to diagnose and start treatment. The authors say they would like to see routine cascade screening of all close relatives of individuals diagnosed with FH.
“It is a lot more common than we first thought,” co-author Professor Gerald Watts told the limbic. “It’s a major public health problem at the moment.”
FH was previously considered to have a prevalence of one in 500 in the general community; however Professor Watts and his colleague Associate Professor Damon Bell from the University of Western found recent evidence suggesting the prevalence is between one in 200 and one in 350.
“These prevalence figures relate to the general population, and while FH is present in all ethnic groups, communities with gene founder effects and high rates of consanguinity, such as the Afrikaans, Christian Lebanese and Québécois populations, have a higher prevalence of the condition,” they wrote.
Although most people with FH are undiagnosed, Professor Watts said it still reduced the catabolism of low-density lipoprotein cholesterol (LDL-c) and increases rates of premature atherosclerotic cardiovascular disease (CVD).
“FH is a silent condition that many people don’t know about until they have a heart attack,” he said.
Talking to the limbic from Rome, where he is presenting, Professor Watts said anyone with high cholesterol should be tested for FH, bearing in mind that only about one in five will test positive.
This was where cascade screening became important, he said.
“What we need to do is hone in on the people who have tested positive – once identify them you have an index and then you can test close family members.”
Identifying the condition early in children can improve their cardiovascular disease (CVD)-free survival by 30 years of age compared with their untreated parents, the authors found.
“Lifestyle modifications and statins from 8 years of age can reduce the progression of atherosclerosis to the same rate as unaffected siblings over a 10-year period,” they wrote
A child is considered likely to have FH if they have:
- a low-density lipoprotein cholesterol (LDL-c) level ³ 5.0 mmol/L
- a family history of premature CVD and an LDL-c level ³ 4.0 mmol/L
- a first-degree relative with genetically confirmed FH and an LDL-c level ³ 3.5 mmol/L
However, Professor Watts said there were still some hurdles to overcome.
“Although we have recently shown that genetic testing is cost-effective in the cascade screening setting ($4155 per life year saved), only a few centres in Australia have this facility and testing is currently not Medicare rebatable,” they wrote.
“However, combining increased awareness of the benefits of identifying people with FH with the reducing analytical costs may increase the use of genetic testing. This in turn could guide advocacy and lobbying Medicare to support genetic testing for FH.”
Professor Watts said diagnosing children at a young age also presented valuable opportunities to promote healthy diet, prevent the child from taking up smoking and monitor blood pressure.
In severe cases statins can be used to attain therapeutic LDL-c targets and hence redress the residual risk of atherosclerotic CVD
“The testing of children usually raises some issues,” Professor Watts said. “Whether you ought to treat them depends on the risks.”
In addition to this, there have been significant advances in the care of individuals with FH in recent years. PCSK9 inhibitors have proven capabilities in allowing more patients already on statins to attain therapeutic LDL-c targets and hence redressing the residual risk of atherosclerotic CVD.
In a bid to improve national data that will help FH researchers develop better management and treatment strategies, the FH Australasia Network has set up a national registry.
Professor Watts said the registry was essentially an enabling tool to draw attention to the condition, education doctors and specialists, promote cascade testing, provide data for research and help with health policy and planning.
“It was launched less than a year ago and is going very well,” he said.