Addition of Routine Blood Biomarkers to TIMI Risk Score Improves Predictive Performance of 1-year Mortality in Patients with ST-segment Elevation Myocardial Infarction

Background: Several biomarkers have been proposed as independent predictors of poor outcomes in ST-segment elevation myocardial infarction (STEMI). We investigated whether adding information obtained from routine blood tests including hypoxic liver injury (HLI), dysglycemia, anemia, and high neutrophil to lymphocyte ratio (NLR) could improve the prognostic performance of the TIMI risk score for the prediction of 1-year mortality. Methods: A total of 1057 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) between 2007 and 2014 were retrospectively enrolled from 4-regional hospitals. HLI and dysglycemia were defined as serum transaminase >twice the normal upper limit and glucose <90 or >250 mg/dL, respectively. The effect of adding biomarkers to the TIMI risk score on its discriminative ability was assessed using c-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Results: The 1-year mortality rate was 7.1%. The best cutoff value of NLR for the prediction of 1-year mortality was 4.3 (sensitivity, 67%; specificity, 65%). HLI (HR, 2.019; 95% CI, 1.104-3.695), dysglycemia (HR, 2.535; 95% CI, 1.324-3.923), anemia (HR, 2.071; 95% CI, 1.093-3.923), and high NLR (HR, 3.651; 95% CI, 1.927-6.918) were independent predictors of 1-year mortality. When these 4 parameters were added to the TIMI risk score, the c-statistic significantly improved from 0.841 to 0.876 (p<0.001), and the NRI and IDI were estimated at 0.203 (95% CI, 0.130-0.275; p<0.001) and 0.089 (95% CI, 0.060-0.119; p<0.001), respectively. Conclusions: The addition of HLI, dysglycemia, anemia, and high NLR to the TIMI risk score may be useful for very early risk stratification in patients with STEMI receiving primary PCI.