In deciding whether a patient requires therapy to prevent an atherosclerosis-related heart attack or stroke, physicians usually rely heavily on measurements of cholesterol in the person’s blood. But that approach misses a great many vulnerable individuals. Several studies suggest that measuring blood concentrations of C-reactive protein – or CRP, a marker of inflammation – could add useful information. Indeed, in one recent report, Paul M. Ridker of Brigham and Women’s Hospital demonstrated that examining both CRP levels (which cannot be predicted from cholesterol measures) and cholesterol levels provides a more accurate indication of risk than assessing cholesterol alone.
Ridker grouped cholesterol levels in the general adult population into five progressively rising ranges (quintiles) and, separately, divided CRP levels into quintiles as well. Then he determined the relative risk faced by people having different combinations of cholesterol and CRP values. That is, he assigned a danger level of “one” to individuals whose cholesterol and CRP values both fell in the lowest quintile (front corner) and calculated how much that risk multiplied in adults having other permutations of cholesterol and CRP measurements.
He found that high CRP values signify markedly elevated risk for heart attack or stroke even in individuals with seemingly reassuring cholesterol values. For instance, people with average (third-quintile) cholesterol levels and the highest CRP levels face much the same peril as those who have the highest cholesterol and lowest CRP levels. And subjects having the highest values for both cholesterol and CRP confronted the greatest risk of all. Encouraged by such results, researchers now hope to undertake a large study assessing whether basing such treatment decisions on combined CRP and cholesterol testing will save lives.