If the existing guidelines for treating cholesterol and high blood pressure do not change, a newly introduced heart risk calculator could result in 16 million individuals losing eligibility for preventive treatments. This loss of access to cholesterol and blood pressure medications might lead to an additional 107,000 heart attacks and strokes over the next decade, but it could also lower the incidence of new diabetes cases by 57,000 in the same timeframe. These results highlight the necessity to reassess the current treatment thresholds alongside updated risk assessments to tailor therapy effectively and enhance clinical decision-making.
A new cardiovascular disease risk calculator has been introduced which evaluates a patient’s likelihood of experiencing a heart attack or stroke. Although it is more accurate than its predecessor, keeping existing guidelines for cholesterol and blood pressure treatment unchanged could result in some unintended outcomes, according to researchers from Harvard Medical School.
The research, published on July 29 in JAMA, predicts that the new risk calculator would leave almost 16 million individuals ineligible for treatment based on the existing guidelines that direct clinical decisions on cholesterol and blood pressure medications. This impact would be particularly noticeable among men aged 50 to 69. The expected decrease in access to statin and blood pressure treatment could lead to an additional 107,000 heart attacks and strokes over the next ten years, according to the analysis.
“The key message from our research is that alongside new risk estimations, we must also rethink treatment thresholds, as it can fundamentally change the recommended care for millions of Americans,” explained James Diao, the study’s first author and a resident physician at Brigham and Women’s Hospital.
The introduction of the new risk assessment tool presents an excellent opportunity to reevaluate these treatment thresholds, the researchers noted.
“Cardiovascular disease prevention revolves around two main aspects: predicting risk and deciding when treatment is necessary to prevent heart attacks or strokes. I would be worried if we modify only one aspect without reviewing the treatment guidelines,” stated Raj Manrai, the study’s senior author and an assistant professor of biomedical informatics at HMS.
Regular updates of risk estimates
Assessing an individual’s risk of having a heart attack or stroke over ten years has been crucial for preventing cardiovascular diseases in healthy individuals and avoiding recurrence in those with prior incidents. This personalized risk prediction, along with public health initiatives, has been instrumental in reducing the toll of cardiovascular disease, which remains the leading cause of death in the U.S. and globally, despite significant advancements in diagnosis and treatment over recent decades.
In November 2023, the American Heart Association launched an updated version of the calculator named PREVENT, designed with more recent population data reflecting changes in cardiovascular disease patterns over the last 10-20 years. This new tool offers 10-year risk estimates for individuals aged 30 to 79 and 30-year risk estimates for those aged 30 to 59. Similar to its 2013 predecessor, the new calculator includes standard cardiovascular indicators like cholesterol and high blood pressure, but it also adds factors such as kidney function. Unlike the earlier version, PREVENT does not consider race, recognizing it as a social construct rather than a biological one. Furthermore, the new calculator allows for the inclusion of blood sugar levels, urine protein, and geographic factors, and suggests initiating risk assessments at the age of 30 instead of 40.
While the American Heart Association and the American College of Cardiology have not yet officially endorsed this new calculator, some healthcare providers have begun to utilize it to inform patient management.
Projecting the clinical impact of the new calculator
The researchers based their predictions on data from nearly 7,700 individuals aged 30 to 79 participating in the U.S. National Health Examination and Nutrition Survey, applying both the 2013 and 2023 risk calculators to evaluate risk and outcomes.
The analysis indicated that the new risk calculator would classify nearly half of the U.S. population into lower risk categories. Conversely, fewer than 0.5 percent of individuals would be reassigned to higher risk categories with the new tool.
The authors then assessed the eligibility for statin and blood pressure medications under current guidelines, which recommend treatment for many at intermediate to high risk and discussions for those at borderline risk.
According to the new risk classification and existing treatment criteria, over 14 million people would no longer qualify for cholesterol-lowering medications, while 2.6 million would lose eligibility for hypertension treatments.
Changes in medication access
Using the new risk calculator, 67.5 million people would be advised to start taking statins, a decrease from 81.8 million under the 2013 guidelines. The most significant changes would affect men, adults in their 50s and 60s, and Black individuals. Although the PREVENT calculator can estimate risks for younger patients (ages 30-79) compared to the previous tool calibrated for ages 40-79, very few individuals aged 30-39 would qualify for treatment. The researchers do suggest, however, that using the new calculator for this younger demographic could provide insights for better long-term monitoring and prevention.
Additionally, the analysis found that the reduced reliance on cholesterol-lowering statins could prevent nearly 57,000 new cases of diabetes, as statins have been associated with an increased diabetes risk.
For blood pressure medications, 72.7 million adults would be eligible under the new risk formula, decreasing from 75.3 million with the previous calculator. The majority of the changes would take place among men aged 50 to 69, with 2 percent of Black adults becoming ineligible for blood pressure treatment compared to 1.4 percent of white adults.
Overall, the new risk calculator would lead to 15.8 million individuals newly ineligible for statins and hypertension treatments, the analysis revealed.
Increased risk of heart attacks and strokes
To assess the potential rise in heart attacks and strokes resulting from these changes, the researchers estimated the risk reduction that would be lost due to the lack of preventive treatment among those newly ineligible. Essentially, they gauged the number of heart attacks and strokes that would no longer be prevented if treatment were discontinued.
The authors project that this decrease in medication eligibility could lead to 107,000 more heart attacks or strokes over the next decade.
Additionally, the exclusion of race from the revised calculator impacts Black Americans by assigning them a lower risk profile compared to the earlier tool that considered race as a factor. However, the analysis did not predict a significant increase in heart attacks and strokes among newly ineligible Black Americans compared to their white counterparts. This unexpected outcome likely results from pre-existing inequalities in access to preventive cardiovascular care. The researchers highlight that since many Black individuals do not receive the preventive advantages of statins and blood pressure medications initially, the loss of eligibility will not drive an increase in cardiovascular events.
“We initially assumed that if Black individuals became disproportionately ineligible for statins, they would experience a proportional rise in heart attacks and strokes, but our findings contradicted this assumption,” Diao remarked. “This likely arises from the fact that fewer Black Americans have access to these medications and recommended care, to begin with. It’s an example where two wrongs don’t make a right.”
Making treatment decisions
While the significance of risk thresholds is clear at a population level, their implications on individual care decisions must also be acknowledged, the researchers emphasize. At the individual level, treatment choices should extend beyond a risk calculator, as no assessment can completely encapsulate every patient’s unique risk profile.
The researchers stress that individualized risk evaluations and treatment decisions should involve more than just inputting data into a calculator. While calculating a patient’s risk is an essential first step, it is crucial to refine that risk based on further information from the patient, such as family history, lifestyle, and other health conditions that could contribute to cardiovascular issues but may not be covered in the calculator. It is equally important for doctors to understand the patient’s preferences regarding risk tolerance versus possible treatment side effects.
“The nuanced decision-making necessary in a physician’s office means that after thorough discussions, two patients with identical risk evaluations might end up following different treatment plans,” Manrai noted. “And that is beneficial.”
