Complement C3 and C-reactive protein in male survivors of myocardial infarction

Background: Inflammatory processes play a fundamental role in the development of cardiovascular disease. Objectives: To compare the associations of complement C3 and C-reactive protein (CRP) with myocardial infarction (MI) and cardiovascular risk factors. Methods: 342 Caucasian male subjects aged <= 65 years with MI and 193 Caucasian age matched healthy male control subjects were recruited. C3 and CRP were measured by ELISA. Results: C3 and CRP were significantly higher (p<0.001) in patients compared with healthy subjects (patients vs. healthy subjects, C3: 1.22 gL(-1) vs. 1.00gL(-1); CRP: 1.41 mg L-1 vs. 0.72 mg L-1). In a logistic regression model, including conventional cardiovascular risk factors, C3 was independently associated with MI (odds ratio fora 1 S.D. increase in C3: 2.29[1.58, 2.92]); and this association remained after including CRP and/or fibrinogen in the model. CRP was independently associated with MI after accounting for conventional risk factors (odds ratio for a I S.D. increase in CRP: 1.47 [1.16,1.87]), however, this association was lost when C3 and/or fibrinogen were included in the model. Receiver operating characteristic (ROC) analysis indicated that the model which best predicted MI was the model including C3 and fibrinogen. Conclusions: These data suggest that elevated C3 is independently associated with MI and that elevated C3 may be a more specific marker of the inflammatory processes underpinning MI than CRP. (C) 2008 Published by Elsevier Ireland Ltd.