Simple Non-Lab Methods As Good As Lab Tests At Predicting Cardiovascular Disease Risk

In a new study from Brigham and Women's Hospital (BWH), researchers show that methods using non-laboratory-based risk factors predict cardiovascular events as accurately as more costly laboratory-based tests.

"Using non-laboratory tests could simplify risk assessment in countries where laboratory testing is inconvenient or unavailable," said Thomas Gaziano, MD of the Division of Cardiovascular Medicine at BWH and lead author of the study.

Using a previous cohort developed in the early 1970's and comprised of 14407 US participants between the ages of 25 -74, Gaziano and colleagues re-analysed the NHANES I study. The follow-up study population included 6186 participants who did not report a history of cardiovascular disease (heart attack, heart failure, stroke, angina), or cancer. The lab-based method, which required blood-tests, looked at age, systolic blood pressure, smoking status, total cholesterol, reported diabetes status, and current treatment for high blood pressure. The non-lab method substituted body-mass index for cholesterol.

Researchers found that in the 6186 people initially not reporting a history of CVD, there were 1529 first-time cardiovascular events and 578 deaths due to cardiovascular disease over a 21 year period. Both lab and non-lab methods calculated a number called the c-statistic to assess cardiovascular risk prediction, and for both men and women, lab and non-lab methods gave similar c-statistics. Furthermore, the non-lab method correctly classified patients at the same rate as the lab method across four commonly used levels of risk used in guidelines around the world, suggesting good calibration.

Study authors add that the cost for developing nations to perform cholesterol tests on patients who were at risk for the development of cardiovascular disease could use more than 10 percent of the nation's health care budget, which adds little benefit to non-lab tests. Non-lab test are effective at collecting the appropriate information to determine risk quickly and in a non-invasive way.

"Approximately 80 percent of cardiovascular deaths occur in developing countries where assessment of patients at high risk is an important strategy for prevention. Since developing countries have limited resources for laboratory testing, cheap, simple and effective, non-lab methods of testing would help immensely," said Gaziano.