The association between C-reactive protein on admission and mortality in patients with acute myocardial infarction

Objective. In patients presenting with acute myocardial infarction the pathophysiologic and prognostic value of serum C-reactive protein is not well defined. This study assessed the association between serum C-reactive protein levels on admission and mortality in patients admitted because of acute myocardial infarction. Design. Retrospective cohort study. Setting. Tertiary care centre. Patients. A total of 729 patients with acute myocardial infarction admitted within a period of 3 years. Main outcome measures. C-reactive protein levels on admission, cardiovascular risk factors and survival within the observational period. Results. Within the 3-year observational period, 118 patients died of a cardiovascular cause. With increasing serum C-reactive protein levels (< 0.5, 0.5 to < 2, 2 to < 5, 5-10 and > 10 mg dL(-1)) mortality also increased (14%, 19%, 20%, 39% and 28%, respectively). When controlling for the confounding effect of age, thrombolytic treatment, the time interval between onset of pain and admission, smoking, diabetes mellitus, hypercholesterolemia, hypertension, and elevated creatine kinase on admission in a multivariate Cox regression model, there was only a weak and nonsignificant association between increased serum C-reactive protein and the risk of death. Conclusions. Patients with elevated concentrations of serum C-reactive protein admitted to the hospital because of acute myocardial infarction are at an increased risk of dying. This association is however, largely explained by other baseline variables, in particular by an estimate of the duration of myocardial ischaemia. If C-reactive protein measured by means of an ultra-sensitive assay is more suitable for risk stratification of unselected patients with acute myocardial infarction, needs further study.