Lack of association of C-reactive protein and coronary calcium by electron beam computed tomography in postmenopausal women: implications for coronary artery disease screening

Abstract

OBJECTIVES

We sought to test the hypothesis that C-reactive protein, a marker of inflammation, would correlate positively with coronary calcium, a marker of atherosclerosis, in postmenopausal women.

BACKGROUND

High sensitivity testing for C-reactive protein (hsCRP) has recently been shown in large population studies to predict cardiac events in asymptomatic postmenopausal women. Coronary calcification determined by electron beam computerized tomography (EBCT) has also been suggested to be predictive of cardiac events in women.

METHODS

We performed hsCRP testing and determined calcium scores by EBCT in 172 asymptomatic postmenopausal women (mean age: 64.5 ± 7.9 years) at risk for cardiac disease. Risk factors were determined by history, physical, electrocardiogram, exercise testing, and lipoprotein profiles.

RESULTS

Calcium scores ranged from 0 to 2618. For analysis, calcium scores were divided into three groups; none (0 to 10), minimal (>10 to 50), and significant (>50). Overall, there was no significant positive relationship between hsCRP level and calcium score. Specifically, the hsCRP levels (mg/dl) were 0.24 ± 0.43, 0.33 ± 0.47 and 0.17 ± 0.32 (medians 0.11, 0.15, and 0.06) for women with none, minimal, and significant coronary calcification, respectively. In subgroup analysis, a similar lack of positive association was observed after stratification by smoking status and by hormone replacement therapy use, two factors known to increase hsCRP.

CONCLUSIONS

In contrast to our a priori hypothesis, we found no evidence of a positive association between hsCRP and calcium score by EBCT. These data thus raise the possibility that hsCRP and EBCT calcium score reflect different pathologic processes, an issue with implications for coronary artery disease screening.