Objective To investigate the possible influencing factors of serum high-sensitivity C-reactive protein (hs-CRP) levels on admission, and to assess the the association between admission serum hs-CRP levels and mortality in patients admitted because of acute myocardial infarction (AMI).
Methods A total of 609 patients with AMI from Peking University People's Hospital between January, 2005 and December, 2009 were enrolled in this retrospective analysis. The clinical data including age, gender, traditional risk factors of atherosclerosis, history of cardiovascular disease, laboratory test results including hs-CRP, lipid, serum creatinine, myocardial enzymes, and echocardiographic results were collected. The potential influencing factors of hs-CRP levels, and correlations between admission hs-CRP and in-hospital outcomes were statistically analysed by the use of logistic regression.
Results The median serum hs-CRP level of 609 patients with AMI is 8.22 mg/l (3.40 mg/l, 12.99 mg/l). Patients with hs-CRP level>3.0 mg/l accounted for 78.1%. Hs-CRP correlated positively with the time interval from onset of pain until the hs-CRP levels were tested and myocardial enzymes and negatively with statin use before admission. With increasing hs-CRP levels (<1.0, 1.0 to 3.0, >3.0 to 10.0 and >10.0 mg/l) left ventricular ejection fraction decreased, while incidence rate of aneurysm formation, ventricular septal perforation, mitral valve prolapse and apical thrombus was no significant difference. A total of 22 (3.6%) patients died during hospitalisation, of which 21 (3.4%) for cardiac death. Increased hs-CRP levels were associated with increased risk of in-hospital death (OR=1.134, 95% CI, 1.046 to 1.228, p=0.002). When controlling for the confounding effect of age, gender, traditional risk factors of atherosclerosis, history of cardiovascular disease, cardiac function and cardiac enzymes, patients with hs-CRP≥11 mg/l had a 3-fold increased risk of death compared with those hs-CRP<11mg/L (OR=4.009, 95% CI, 1.175 to 13.673, p=0.027). After further adjusted for renal function, correlation between elevated hs-CRP and death reduced below the significant level (OR=2.519, 95% CI, 0.673 to 9.433, p=0.170).
Conclusions There was a weak association between admission serum hs-CRP levels and in-hospital mortality in patients with AMI. The prognostic value of hs-CRP levels at admission was limited.