For Predicting CV Risk, Life’s Essential 8 Doesn’t Add Much to Simple 7

The American Heart Association’s health assessment tool Life’s Essential 8 (LE8), which launched in 2022, isn’t any better at predicting future cardiovascular disease risk than its predecessor, Life’s Simple 7 (LS7), an analysis of observational data suggests.

This is in spite of the fact that the updated score includes a new factor, sleep, as well as more nuanced gradations for each of the seven other factors: dietary quality, physical activity, exposure to cigarette smoking, body mass index, fasting blood glucose, total cholesterol, and blood pressure.

George Howard, DrPH (University of Alabama at Birmingham), senior author of the paper, published recently in Circulation, said a common misconception is that sleep was the main difference between LE8 and LS7. “That’s what everybody says. But when we sat down to calculate Life’s Essential 8, [it became clear] they did a lot of other things—they did a boatload of other things,” he told TCTMD.

Originally, Life’s Simple 7 was designed as a tool to be “simple and accessible for clinicians and patients, and also to contain actionable items,” said Howard, adding that it succeeded in these goals. Most of the information could be obtained easily and had three levels of health for each domain, he noted. “Other than getting your cholesterol and fasting glucose [levels], I could do a Life’s Simple 7 evaluation for you in 5 minutes, [even] 3 minutes.”

Life’s Essential 8, on the other hand, is expressed not as three domains per metric, but as semicontinuous variables. Physical activity, for example, is categorized into eight levels.

Based on this added level of intricacy, the research team had expected Life’s Essential 8 would come out ahead. “We went into this because I was confident this was going to crush [Life’s Simple 7],” he said. The fact that it didn’t “basically was a big-time surprise for us.”

Donald Lloyd-Jones, MD (Northwestern University Feinberg School of Medicine, Chicago, IL), past president of the American Heart Association, chaired the writing group behind Life’s Essential 8 and led the effort to create Life’s Simple 7 in 2010. He says that the current analysis misses the point of the two tools, as well as the ideas behind the upgrade from LS7 to LE8.

“The main goal of measuring and quantifying [cardiovascular health] is to assess someone's health status today, and help them monitor it over time. Neither the original LS7 nor the new LE8 were intended to be used primarily as risk-prediction scores,” Lloyd-Jones commented in an email to TCTMD. “If that were the goal, they would have been constructed very differently. So this [new analysis] is not too surprising. For the purposes of risk prediction in middle-aged adults, there are guideline-recommended tools already available.”

On the other hand, there’s much data to show that measuring LS7 or LE8 is a way for clinicians and patients to improve long-term health and longevity, he added. While these two tools “work well to measure health at any stage of life, they are particularly useful for children and young adults, for whom there are no other risk-prediction scores,” Lloyd-Jones specified.

Both of these metrics are meant to facilitate conversations between patients and their doctors, and help patients better understand their health status at the time, he explained. “The upgrade from LS7 to LE8 was not designed to improve risk prediction but to improve health assessment, which it demonstrably does, as shown in other papers.”

Howard pointed out, however, that regardless of whether the two tools were designed for risk prediction, many people may view them in this way. It’s intuitive to think that “changing these habits would be associated with a change in cardiovascular risk,” he noted. Researchers, too, are using the tools as a lens through which health behaviors can be viewed: a search of PubMed turns up nearly 300 hits for Life’s Simple 7 and 85 hits for Life’s Essential 8.

Fairly small changes in either of the scales, if you’re doing poorly, are important—you can really reduce your risk. George Howard

For the current study, the researchers calculated both the LS7 and LE8 for 11,609 Black and white individuals free of baseline CVD who were enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study from 2003 to 2007. A total of 1,736 events occurred over a median follow-up of 12.8 years.

The two tools predicted nearly identical 10-year risk of CVD across the distribution of risk, with a correlation of 0.87. “Basically, because they’re so highly correlated, it can’t be that much of an improvement when going from LS7 to LE8,” said Howard.

The relationship between score and risk “is remarkably linear,” Howard said, and was concordant between the scores for participants at the same relative position in the LS7 and LE8 distribution. For participants in the 99th percentile of LS7 and LE8, the risk of incident CVD (coronary heart disease or stroke) was around 5%. For those in the 1st percentile, risk was nearly quadrupled at around 20%. “That’s a huge difference. Both of these scales [can] identify people at extraordinary risk. Twenty percent risk in a 10-year period: wow, I don’t want to be that,” he commented.

Moreover, decrease in risk accompanying each drop in score was greatest among those on the higher and lower ends of the spectrum. “Fairly small changes in either of the scales, if you’re doing poorly, are important—you can really reduce your risk. If I drop from a Life’s Simple 7 score of 11 to 12, I go from 22% risk to 12% risk. That’s good,” said Howard.

Adjusted for age, race, and sex, the C-statistics for the LS7 and LE8 models were 0.691 and 0.695 (P for difference = 0.12).

“Both LS7 and LE8 were associated with incident CVD, with discrimination of the two indices practically indistinguishable. As a simpler metric, LS7 may be favored for use by the general population and clinicians,” the researchers conclude.