Assessment of cardiovascular risk
The guideline on assessing cardiovascular risk in adults includes the global risk assessment tool, which "provides a quantitative clinical assessment to guide clinical care," said Dr. Donald M. Lloyd-Jones, one of the cochairs in the work group that wrote this guideline.
Dr. Donald Lloyd-Jones
The guideline recommends lifetime risk alongside 10-year risk, said Dr. Lloyd-Jones, chair and professor of preventive medicine at Northwestern University, Chicago. The 10-year risk equations predict the risk of MI and stroke, while previous risk equations focused only on the risk of coronary heart disease events. "We realized quickly that we were leaving a lot of risk on the table by not also including stroke in our risk assessment algorithm," which is particularly important in female and black patients, he said.
Estimating lifetime risk may be particularly useful for identifying younger patients who have a low 10-year risk "but who have unhealthy lifestyles or risk factors that will put them at substantial risk for developing cardiovascular disease in the longer term," he added.
The risk equations for non-Hispanic white men and women and for black men and women are based on data from NHLBI-funded population-based studies, including the Coronary Artery Risk Development in Young Adults Study (CARDIA), the Atherosclerosis Risk in Communities Study (ARIC), and the Cardiovascular Health Study (CHS), as well as the Framingham Heart Study. These require input of age, sex, race, total and HDL cholesterol levels, blood pressure, blood pressure treatment status, and current smoking and diabetes status, which were identified as the best predictors for 10-year risk, Dr. Lloyd-Jones said.
Other risk markers were considered, but were not included because there was not sufficient information to warrant their inclusion in the equations. Until risk-predictor equations are developed for Hispanics, Latinos, and Asian-Americans, as relevant data become available, the risk equations for white men and women should be used for other races and ethnic groups in the United States, he said.
Based on review of the literature on newer risk markers, the work group determined that four markers "may be considered" in refining risk estimates, if there is uncertainty after performing the risk equations: family history of premature cardiovascular disease in a first degree relative, coronary artery calcium score, measurement of high sensitivity of C-reactive protein (CRP), and measurement of ankle-brachial index. The evidence for using other markers was insufficient, and "we explicitly recommend against performing carotid intimal medial thickness measurement," because of evidence that there is no additional benefit of this test, Dr. Lloyd-Jones said.
The guideline provides information on how to incorporate risk assessment into clinical practice settings, and includes an Excel spreadsheet that can be used to calculate risk, said Dr. Lloyd-Jones. Risk equations can also be programmed into electronic health records.
Dr. John Rumsfeld, acting national director of cardiology for the Veterans Health Administration, views the change in cholesterol treatment recommendations as "a course correction," rather than a radical change in direction. "These guidelines are based on an objective review of the evidence – and that evidence is clear: There is no evidence for treating to specific target numbers for cholesterol. Yet, there is clear and strong evidence for the use of statin medications for people at elevated risk for heart disease and stroke," he said.
"The new treatment approach is more patient centered; it is about treating those who are most likely to benefit from taking a chronic medication; it is about reducing their risk with proven medicines; and it also reduces patient burden by lessening the need for repeat testing and taking additional, unproven medications," he said in an interview.
Over a year ago, the VA health care system dropped its national performance measure for treating to an LDL-cholesterol below 100 mg/dL, based on an independent review of the evidence. Using an approach that is similar to that recommended in the new guideline, the VA implemented a performance measure that emphasized the use of statin medication in patients at elevated risk. "The change from treating targets to treating risk leads to fewer patients being overtreated with unproven medications, and reduces the burden on patients of repeated blood testing and additional medications to take," said Dr. Rumsfeld, also professor of medicine at the University of Colorado, Denver. In addition, the change reduces repeat blood tests and extra medication use, reducing costs to the health care system, he pointed out.
"Instead of repeated laboratory testing, and uptitrating medications or adding additional medications for patients to take with possible side effects, this approach emphasizes initiating treatment with proven medications for those at risk," he said.