New cholesterol guidelines could reduce heart attacks, strokes: study

By Megan Brooks

NEW YORK (Reuters Health) - Widespread adoption of the new cholesterol guidelines would significantly reduce new cardiovascular events, say cardiologists from Texas.

"This is one of the first studies to carefully predict the implications of the new guidelines in the general population beyond just the amount of increase in statin use," Dr. Amit Khera, director of the preventive cardiology program at UT Southwestern in Dallas, said in a statement.

"Does it look like these new guidelines will prevent heart attacks and strokes? The answer is, 'yes,'" he said.

Introduced in November 2013, the American College of Cardiology/American Heart Association (ACC/AHA) Cholesterol Guidelines recommend fixed-dose statin treatment based on cardiovascular risk, rather than blood cholesterol targets (http://bit.ly/1drbW33).

It's been estimated that adoption of the new guidelines in place of the National Cholesterol Education Program/Third Adult Treatment panel (ATPIII) recommendations will boost eligibility for statin treatment by 11%, representing 12.8 million Americans.

"Although the magnitude of change in statin eligibility has been a topic of focus, the impact of the new guidelines on atherosclerotic cardiovascular disease (ASCVD) event rates and efficiency of additional statin use cannot be determined from the studies published to date," Dr. Khera and colleagues note in Circulation: Cardiovascular Quality and Outcomes, online August 5.

To assess the potential impact on event rates, they did an analysis of adults 30 to 65 years old examined in 2000-2002 and actively followed as part of the long-running Dallas Heart Study who would have newly qualified for statin use under the new guidelines.

A total of 2,848 adults were assessed for statin eligibility according to both guidelines. Overall, 17.2% of individuals were classified as statin-eligible by the old guidelines and 22.0% by the new guidelines, a net increase of 4.8% and a relative increase of 27.9%.

"The ASCVD event rate among newly statin-eligible individuals was 15.8% with an estimated one ASCVD event prevented for each additional 14 patients treated with high-dose statins and 21 treated with moderate-dose statins," the investigators report.

"The net increase in statin eligibility was 37.1% among participants with ASCVD events and 3.9% among participants without ASCVD events, resulting in a net reclassification improvement of 0.332 (P<0.001)," they say.

The team calculates that applying the new guidelines in place of the old would result in an additional 3.6 to 4.9 prevented ASCVD events for every 1,000 people screened and accordingly treated (using a risk-reduction factor of 30% to 45%, depending on the statin dosage).

Projecting these findings onto the larger Dallas County population, they estimate that 4,479 to 4,771 ASCVD events would be prevented in individuals 30 to 65 years of age over a 10-year period by following the new cholesterol guidelines.

Summing up, the researchers say, "Our findings are consistent with a recent report from the National Health and Nutrition Examination Surveys and suggest that, among individuals <60 to 65 years, adopting the ACC/AHA guidelines would result in a modest absolute increase in statin eligibility. Beyond reporting on additional statin use, we apply actual event rates to show that in this age group, additional statin use with adoption of the new guidelines seems reasonably efficient and effective."

Dr. Eugenia Gianos, assistant professor and cardiologist at NYU Langone Medical Center, reviewed the analysis for Reuters Health.

"Since the new guidelines came out there have been multiple applications of the guidelines to different cohorts to validate whether or not the predictive value holds up," she told Reuters Health. "This one is useful because it's a very large cohort and a diverse population, half of which were women. The downside is the age range. The mean age was only 43. In this particular age range, the guidelines were very useful in the patients they reclassified, giving more credit to the new guidelines."

However, the analysis doesn't look at patients above age 65. "A lot of the criticism of the guidelines is that some of the overuse of statins might be in an older population where benefit might not be derived from the statin if in fact their true cardiovascular risk in the long term is not actually as high as we would have thought," Dr. Gianos explained.

"I think when physicians are dealing with an older patient who doesn't have a lot of risk factors other than age, they need to use individual judgment and other potential factors that might help them establish risk," Dr. Gianos said.

"The benefit of the new guidelines is they are very simple to apply and that may broaden their use overall. However, there are still a number of physicians who have not accepted the new guidelines because they are very different from the prior guidelines," she added.

SOURCE: http://bit.ly/VPEPTg

Circ Cardiovasc Qual Outcomes 2014.

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