OBJECTIVE: To investigate whether hs-CRP and IL-6 provide additional diagnostic value beyond that achieved by the HEART score in patients with chest pain suggestive of acute coronary syndrome (ACS) admitted to the emergency department (ED).
METHODS: This was a post hoc analysis using data from the RACING-MI study. Baseline data, including hs-CRP and IL-6 levels, were analyzed using the plasma from the biobank. A total of 818 patients with chest pain suggestive of ACS were included in this analysis. Of these, 98 were diagnosed with ACS (12%). Logistic regression was used to identify the independent predictors of ACS development in patients with chest pain.
RESULTS: hs-CRP levels >2 mg/L were observed in 50% of all ACS cases. IL-6 levels >1.3 pg/mL were observed in 71% of all ACS cases. hs-CRP had a sensitivity of 50% and specificity of 51% for the diagnosis of ACS, whereas IL-6 had a sensitivity of 71% and specificity of 29%. The diagnostic likelihood ratios for ACS was 1.0 for hs-CRP>2 mg/L and IL-6 > 1.3 pg/mL, respectively. Logistic regression analysis revealed that age, male gender, and ongoing smoking were associated with ACS in patients with acute chest pain. No association was found between IL-6 or hs-CRP level and ACS. This was observed for both IL-6 and hs-CRP, whether assessed on a continuous scale or using prespecified cut-off values.
CONCLUSION: Among the 818 patients admitted to the ED with chest pain suggestive of ACS, neither hs-CRP nor IL-6 provided an independent added diagnostic value. Our results suggest that inflammatory markers have limited diagnostic value in detecting patients with ACS in the ED.