magine your financial adviser using information she gathered from you one day in your mid-30s to guide your investments through your mid-60s. That’s probably not an effective strategy. Yet it’s akin to what cardiologists like us have traditionally done for our patients. We think there’s a better way.
Back in 1998, researchers with the legendary Framingham Heart Study created the first heart risk calculator. Using answers to questions about age, cholesterol and blood pressure levels, tobacco use, and the presence of diabetes, it estimated an individual’s risk of having a heart attack or stroke over the next 10 years. Since then, this calculator has been revised and many others have been developed, including ones that extend the time horizon out to an individual’s lifetime. Yet much to our surprise, the use of these single-point-in-time risk calculators does little to reduce the risk of heart attack or stroke compared with not using such calculators.
We made that finding when we and other colleagues from Northwestern University Feinberg School of Medicine and the London School of Hygiene and Tropical Medicine pooled data from 41 randomized trials looking at the effect of calculating or not calculating cardiovascular risk scores to adults without cardiovascular disease. The trials included nearly 200,000 participants.
Calculating and sharing single-point-in-time cardiovascular risk scores helped reduce cholesterol and blood pressure a small amount, mostly because the scores were used to have patients start taking medications that lowered these two risk factors. But the scores did not decrease the rate of heart attacks, strokes, or other cardiovascular events for three reasons: Doctors often didn’t start patients with high scores on medications to prevent cardiovascular events; single-point-in-time risk scores did not help patients stick with their medications long term; and the overall effects on cholesterol and blood pressure were too modest to influence the rate of cardiovascular disease. The results were published in the Cochrane Database of Systematic Reviews.
For a risk tool to improve outcomes, it must be used regularly and paired with sustained treatments proven to reduce risk over time, including healthy lifestyle changes and, as needed aspirin, cholesterol-lowering statins, and drugs to lower blood pressure. To make better decisions, doctors and patients need information over time on benefits and risks of treatments and behavioral strategies. This is similar to how people rebalance their financial portfolios based on their changing situations and financial risks in the market.
To create a longitudinal risk calculator that incorporates information about an individual’s changing cardiovascular condition over time, we worked with risk experts Dr. Donald Lloyd-Jones from Northwestern University, Dr. David Goff from the National Heart, Lung, and Blood Institute, and Dr. Darshak Sanghavi from the Center for Medicare and Medicaid Innovation. Using this calculator requires two immediate steps — assess baseline cardiovascular disease risk and then calculate the benefits and harms from starting aspirin, a statin, a blood pressure-lowering drug, or smoking cessation and other lifestyle changes, either alone or in combination. During follow-up visits, the individual’s risk is then reassessed and updated based on his or her response to treatment and adoption (or lack of it) of behavioral changes that influence risk.
This new longitudinal risk score, called the Million Hearts Longitudinal ASCVD Risk Assessment Tool is now being tested in a large, randomized trial to see if it is effective at reducing heart attacks and strokes. The trial also will evaluate the effect of providing financial incentives to physicians based on how much they lower the cardiovascular risk of their patients using this calculator.
As we imagine the future of cardiovascular medicine, we predict that longitudinal risk scores will be a better way for doctors and patients to make fully informed and ongoing decisions about the best treatments to prevent heart attacks and strokes.
Kunal N. Karmali, MD, is an instructor in cardiology and Mark D. Huffman, MD, is an assistant professor of preventive medicine and cardiology at Northwestern University Feinberg School of Medicine in Chicago.