Aussies help show why calcium score tests are valuable

Want to know your risk of heart disease? This quick test can help, especially if you’ve stopped taking statins.

Coronary calcium score tests are a valuable and potentially lifesaving tool that help identify heart disease risk, a world-first study of Australian adults has confirmed.

Published in the journal JAMA, it found the Coronary Artery Calcium Score (CACs) worked well for treating those in the precarious “intermediate risk” zone which represents about half of the population.

This is a group who are often overlooked for treatment, but half of these adults have coronary disease.

Around 1.3 million adult Australians live with heart, stroke or vascular disease. Image: iStock

The three-year randomised controlled trial involved 1100 Australians aged between 40 to 70 years and was led by the Baker Heart and Diabetes Institute in partnership with the Menzies Institute for Medical Research, Victorian Heart institute and sites in Perth, Adelaide and Brisbane.

Lead researcher and cardiologist Professor Tom Marwick said CACs were a CT scan of a person’s heart to flag calcium, which identifies the fatty plaques that can narrow and block arteries.

“We don’t think it’s a stand-alone test,” he said. “We think it is part of a strategy for identifying risk and then communicating that risk. It’s a piece of information that’s understandable to the patient.”

He said CACs were also not a replacement for heart health checks, more a valuable adjunct to risk assessment and education.

This is important as around 50 per cent of Australians on statins stop taking the cholesterol-lowering drugs within a year.

The reason, Professor Marwick said, was many felt they were spending money on the drug, but felt the same.

Heart health checks include blood pressure and cholesterol levels and other risk factors such as family history. Calcium checks could be a valuable adjunct.

“Now we can show them this is your coronary system, and here’s the calcium, you have disease. It is a pivotal moment in the patient’s understanding.”

He said there had been a high level of adherence on the trial that the researchers found was about using the technique to educate patients.

“A heart health check as currently configured is a clinical evaluation that includes cholesterol levels and blood pressure and other risk factors (such as family history) to calculate clinical risk,” Professor Marwick said. “I think that’s a great foundation.”

He said these calculators had been used for more than 50 years, but were based on assessing risk in the population.

“When I’m seeing somebody in front of me, they want to know their own individual risk,” Professor Marwick said.

“So when the heart health check or the standard risk calculators say the risk is very low or the risk is very high, I’m good with that. That’s all we need (to decide on treatment).

“But then there’s a big group in the middle, about 40 or 50 per cent of the population, who are at intermediate risk. So there are things that we’re currently not capturing with those risk calculators.

The researchers say CACs are not a replacement for heart health checks, more a valuable adjunct to risk assessment and education.

“Our argument is that where there’s ambiguity, we now have a tool (CACs) to say whether there is disease in that particular person.”

The test gives a “score” that predicts outcome.

Professor Marwick said the data from the study also shows benefit for those with a score of 100 or more who start on statins.

The tests carry an out-of-pocket cost of around $200, but Professor Marwick said “in his personal opinion” CACs in selected circumstances should be funded by Medicare.

“We hope the fact that we’ve got trial data and we’ve also done cost-effectiveness analyses will enable people to revisit this, because coronary disease has a social gradient,” Professor Marwick said. “It means that the people who would most benefit from having tests are the least able to afford it.”