Additional analysis of red blood cell distribution width improves the predictive value of the GRACE 2.0 score for 18-month mortality in patients with acute myocardial infarction

Aim. To identify whether the addition of red blood cell distribution width (RDW) could improve the Global Registry of Acute Coronary Events (GRACE) risk score 2.0 in patients with acute myocardial infarction (AMI). Material and methods. This prospective observational study included 577 AMI patients who underwent coronary angiography within 24 hours after symptom onset. Admission RDW was measured as part of the automated complete blood count. GRACE 2.0 score at admission was calculated. The clinical endpoint was 18-month all-cause mortality. Logistic regression analysis was used to identify predictive values of RDW. Area under the receiver-operator characteristic (ROC) curve (AUC), net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated to evaluate the increment of predictive value for the combination of RDW with GRACE 2.0 score in predicting clinical adverse outcome. Results. The median age of patients was 65 (interquartile range: 56-74) years, while 60,7% were male. During 18-month follow-up, 66 patients (11,4%) died. RDW was positively correlated with GRACE 2.0 score (r=0,16, p<0,001). Multivariate analysis showed that both GRACE 2.0 score and RDW were independent predictors of 18-month mortality (odds ratio 1,025; 95% confidence interval CI 1,013-1,037; p<0,001; and 1,298; 1,087-1,551; p=0,004; respectively). The AUC for predicting 18-month mortality of GRACE 2.0 score, RDW and their combination was 0,795 (95% CI: 0,734-0,856), 0,708 (95% CI: 0,642-0,775) and 0,826 (95% CI: 0,775-0,876), respectively. Addition of RDW in the GRACE 2.0 score enhanced NRI (0,428; p=0,0009) and IDI (0,014; p=0,002). Conclusion. Baseline RDW levels at admission was associated with 18-month mortality in patients with AMI. The inclusion of RDW into GRACE 2.0 score enables more accurate prediction of long-term risk of death compared with GRACE 2.0 score alone.