Comparison of CRP and LDL Cholesterol Levels in the Prediction of First Cardiovascular Events

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Volume 347:1557-1565 November 14, 2002 Number 20

Comparison of C-Reactive Protein and Low-Density Lipoprotein Cholesterol

Levels in the Prediction of First Cardiovascular Events

M. Ridker, M.D., Nader Rifai, Ph.D., Lynda Rose, M.S., E.

Buring, Sc.D., and R. Cook, Sc.D.

ABSTRACT

Background Both C-reactive protein and low-density lipoprotein (LDL)

cholesterol levels are elevated in persons at risk for cardiovascular

events. However, population-based data directly comparing these two

biologic markers are not available.

Methods C-reactive protein and LDL cholesterol were measured at base

line in 27,939 apparently healthy American women, who were then followed

for a mean of eight years for the occurrence of myocardial infarction,

ischemic stroke, coronary revascularization, or death from

cardiovascular causes. We assessed the value of these two measurements

in predicting the risk of cardiovascular events in the study population.

Results Although C-reactive protein and LDL cholesterol were minimally

correlated (r=0.08), base-line levels of each had a strong linear

relation with the incidence of cardiovascular events. After adjustment

for age, smoking status, the presence or absence of diabetes mellitus,

categorical levels of blood pressure, and use or nonuse of

hormone-replacement therapy, the relative risks of first cardiovascular

events according to increasing quintiles of C-reactive protein, as

compared with the women in the lowest quintile, were 1.4, 1.6, 2.0, and

2.3 (P<0.001), whereas the corresponding relative risks in increasing

quintiles of LDL cholesterol, as compared with the lowest, were 0.9,

1.1, 1.3, and 1.5 (P<0.001). Similar effects were observed in separate

analyses of each component of the composite end point and among users

and nonusers of hormone-replacement therapy. Overall, 77 percent of all

events occurred among women with LDL cholesterol levels below 160 mg per

deciliter (4.14 mmol per liter), and 46 percent occurred among those

with LDL cholesterol levels below 130 mg per deciliter (3.36 mmol per

liter). By contrast, because C-reactive protein and LDL cholesterol

measurements tended to identify different high-risk groups, screening

for both biologic markers provided better prognostic information than

screening for either alone. Independent effects were also observed for

C-reactive protein in analyses adjusted for all components of the

Framingham risk score.

Conclusions These data suggest that the C-reactive protein level is a

stronger predictor of cardiovascular events than the LDL cholesterol

level and that it adds prognostic information to that conveyed by the

Framingham risk score.

Source Information

From the Center for Cardiovascular Disease Prevention and the Divisions

of Preventive Medicine (P.M.R., L.R., J.E.B., N.R.C.) and Cardiology

(P.M.R.), Brigham and Women's Hospital and Harvard Medical School; and

the Department of Laboratory Medicine, Children's Hospital and Harvard

Medical School (N.R.) - all in Boston.

Address reprint requests to Dr. Ridker at the Center for Cardiovascular

Disease Prevention, Brigham and Women's Hospital, 900 Commonwealth Ave.

East, Boston, MA 02215, or at pridker@....