Time-dependent prognostic effect of high sensitivity C-reactive protein with statin therapy in acute myocardial infarction

Background: Elevated high sensitivity C-reactive protein (hs-CRP) in acute myocardial infarction (AMI) patients undergoing percutaneous coronary intervention (PCI) has prognostic value for future cardiovascular events. This study aimed to ascertain a valid prognostic time-period for predicting cardiovascular outcome based on baseline hs-CRP in AMI patients undergoing successful PCI on statin therapy.

Methods: Overall, 4410 AMI patients were enrolled from the Korea Acute Myocardial Infarction-National Institutes of Health (KAMIR-NIH) registry. Participants were divided into groups according to cut-off values of baseline hs-CRP (1.0, 3.0, and 10.0mg/L) and statin therapy intensity. The primary outcome was 36-month major adverse cardiovascular events (MACE), a composite of all-cause mortality, any myocardial infarction, and repeat revascularization. The secondary outcome was MACE developed 0-6, 6-12, and 12-36 months after AMI.

Results: The overall incidence of 36-month MACE was significantly higher as baseline hs-CRP increased (by groups: 8.8% vs. 8.6% vs. 10.7% vs. 15.4%, log-rank p<0.001). The prognostic effect of baseline hs-CRP was mostly confined to the first 6 months after AMI (0-6 months MACE by groups: 1.6% vs. 2.3% vs. 4.3% vs. 6.1%, log-rank p<0.001) and attenuated in high-intensity statin users. Six months after AMI, this prognostic effect of baseline hs-CRP was remarkably reduced (6-12 month MACE by groups: 2.4% vs. 2.1% vs. 2.8% vs. 4.0%, log-rank p=0.111, 12-36 month MACE by groups: 4.7% vs. 4.1% vs. 4.0% vs. 6.2%, log-rank p=0.218); however, high-intensity statin treatment showed a consistent improvement in outcome. The observed time-dependent prognostic effects remained consistent following multivariate analysis.

Conclusions: The prognostic impact of elevated hs-CRP at baseline was most evident during the first 6 months after AMI; however, the use of high-intensity statin persistently improved the clinical outcome even after the resolution of inflammatory reactions.