# Simplified heart-risk guideline may miscalculate risk for millions

##### Sep 09, 2010

A method that is widely used to predict the risk of a major coronary event may over- or underestimate risk for millions of Americans, according to a study directed by a researcher at the San Francisco VA Medical Center and the University of California, San Francisco.

The method in question is the simplified version of the so-called Framingham model, which is used to estimate a patient's 10-year risk of a heart attack, stroke, or other coronary event based on risk factors such as age, , blood pressure, and smoking. National guidelines recommend using the risk estimates generated by the Framingham model to classify patients as among one of three risk groups. Guidelines recommend more aggressive strategies to treat cholesterol in patients classified into higher-risk groups.

The original Framingham model uses a complicated mathematical equation to calculate risk, while the simplified version is based on a point system, with a certain number of points for each risk factor.

"We thought there might be significant differences between the two methods, which would have significant impacts on how people are treated for cholesterol," says principal investigator Michael Steinman, MD, a physician at SFVAMC and an assistant professor of medicine at UCSF. "And in fact, that turned out to be the case."

For the study, which appears in the Online First section of the "," the researchers assessed data from 2,543 subjects who participated from 2001 to 2006 in National Health and Nutrition Examination Surveys sponsored by the . The subjects were chosen to be representative of 39 million adults in the United States for whom guidelines recommend using the Framingham method to predict future cardiovascular risk.

For each subject, the researchers calculated risk based on the original Framingham model and on the simplified model, and compared the differences, "which turned out to be substantial for many patients," says Steinman, who is senior author of the paper.

Under the point-based system, 15 percent of the subjects were classified as being at a different level of risk than they were under the original model. Nationwide, say the authors, 5.7 million Americans would be placed into different risk groups using the point-based model than they would be using the original model, with 3.9 million misclassified into higher risk groups and 1.8 million misclassified into lower risk groups.

"Across the group, on average, these statistical differences balance out," says Steinman. "But for individual patients, they are potentially important. A lot of individuals would be treated differently - either more aggressively or less aggressively - using the point-based model."

Steinman notes that the point-based model, which can be completed in a few minutes with pen and paper, was introduced over a decade ago, when computers and personal digital assistants were less powerful and not so common in private medical practices.

"While the point-based system is a substantial improvement over having no standardized method for predicting risk, just about any computer or PDA in use today can calculate the original Framingham model," says Steinman. "This means that your doctor can calculate your risk just as easily using the complex equation, which is likely to be more accurate than the point-based system. So there's not much reason to use the point-based system anymore in most instances."

Steinman cautions that the study was not designed to determine the benefits or harms for individuals who would be treated differently based on the results of the two models.

The study authors note that the next generation of cholesterol guidelines is expected to be released in the near future, and that point-based versions of the new risk model have already been developed, which may result in similar misclassifications.

"With risk prediction models being increasingly used for many different diseases and conditions, this could be a general problem in the field of medicine," predicts Steinman. "In creating simplified risk models, we have to be aware of the potential impact on individual patients."

Explore further: West Africa's Ebola outbreak prompts changes in I.Coast cuisine

Provided by University of California - San Francisco

## Related Stories

#### New tests needed to predict cardiovascular problems in older people more accurately

Jan 09, 2009

A long-standing system for assessing the risk of cardiovascular disease amongst older people should be replaced with something more accurate, according to a study published today on bmj.com.

#### Framingham risk assessment doesn't accurately predict coronary artery disease, study suggests

Apr 21, 2010

If patients with suspected coronary artery disease (CAD) are excluded from further screening because of a low Framingham score, many patients with substantial atherosclerosis (a build-up of plaque inside the arteries) will ...

#### Researchers find that healthy, younger adults could be at risk for heart disease

Jan 12, 2009

Even younger adults who have few short-term risk factors for heart disease may have a higher risk of developing heart disease over their lifetimes, according to new findings by a UT Southwestern Medical Center researcher.

#### Is your heart aging faster than you are?

Nov 26, 2007

Despite the increasing evidence that managing high cholesterol reduces cardiovascular events, many people do not achieve recommended lipid levels. This is due, in part, to patients’ lack of understanding about their risk ...

#### Assessing the real risk of heart disease in young people with low short-term risks

Jan 27, 2009

Risk stratification has become central to strategies for the prevention of coronary heart disease, with the implication that priority is given to those at highest risk (ie, those with established heart disease). However, ...

#### New heart disease risk score should be recommended in the UK, say experts

Jul 08, 2009

A new score for predicting a person's risk of heart disease performs better than the existing test and should be recommended for use in the United Kingdom by the National Institute for Health and Clinical Excellence (NICE), ...

## Recommended for you

#### West Africa's Ebola outbreak prompts changes in I.Coast cuisine

4 hours ago

West Africa's first outbreak of Ebola fever is bad news for gourmets in Ivory Coast, but brings respite from the hunter to species sought out for tasty meat but feared to carry the disease.

#### Ebola has killed 61 in Guinea since January

7 hours ago

The Ebola virus has claimed 61 lives in Guinea out of 109 laboratory-confirmed cases since January, the government said Saturday.

#### Two expats die of MERS in Saudi commercial hub

7 hours ago

Two foreigners died of MERS in the Saudi city of Jeddah, the health ministry said Saturday, as fears rise over the spreading respiratory virus in the kingdom's commercial hub.

#### UAE reports 12 new cases of MERS

7 hours ago

Health authorities in the United Arab Emirates have announced 12 new cases of infection by the MERS coronavirus, but insisted the patients would be cured within two weeks.

#### Filipino tests negative for Middle East virus

19 hours ago

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

#### Philippines boosts MERS monitoring after UAE nurse scare

Apr 19, 2014

The Philippines said Saturday it was stepping up its defences against the deadly MERS virus, with the large numbers of Filipino workers in the Middle East seen as potential carriers.

## More news stories

#### Team identifies source of most cases of invasive bladder cancer

A single type of cell in the lining of the bladder is responsible for most cases of invasive bladder cancer, according to researchers at the Stanford University School of Medicine.

#### Cancer stem cells linked to drug resistance

Most drugs used to treat lung, breast and pancreatic cancers also promote drug-resistance and ultimately spur tumor growth. Researchers at the University of California, San Diego School of Medicine have discovered ...

#### Researchers uncover link between Down syndrome and leukemia

Although doctors have long known that people with Down syndrome have a heightened risk of developing acute lymphoblastic leukemia (ALL) during childhood, they haven't been able to explain why. Now, a team ...

#### 'Chaperone' compounds offer new approach to Alzheimer's treatment

A team of researchers from Columbia University Medical Center (CUMC), Weill Cornell Medical College, and Brandeis University has devised a wholly new approach to the treatment of Alzheimer's disease involving ...

#### Improving newborns' bacterial environment could fend off infections, animal study suggests

Mothers give a newborn baby a gift of germs—germs that help to kick-start the infant's immune system. But antibiotics, used to fend off infection, may paradoxically interrupt a newborn's own immune responses, leaving already-vulnerable ...

#### Study casts doubt on climate benefit of biofuels from corn residue

Using corn crop residue to make ethanol and other biofuels reduces soil carbon and can generate more greenhouse gases than gasoline, according to a study published today in the journal Nature Climate Change.

#### Bulletproof nuclei? Stem cells exhibit unusual absorption property

Stem cells – the body's master cells – demonstrate a bizarre property never before seen at a cellular level, according to a study published today from scientists at the University of Cambridge. The property ...

#### Computational method dramatically speeds up estimates of gene expression

With gene expression analysis growing in importance for both basic researchers and medical practitioners, researchers at Carnegie Mellon University and the University of Maryland have developed a new computational ...

#### Easter morning delivery for space station

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.

#### Google Trends info is placed on inbox duty for subscribers

(Phys.org) —Google Trends has added a new service to its mix, where users can enter email subscriptions for Google Trends, and can be sent notifications on topics of interest, showing them what is popular ...