IJCS | Volume 33, Nº4, July and August 2020

386 Figure 2 - ROC curve for the scoring system in predicting mortality. Area under the ROC curve = 0.868 (95% CI 0.818 - 0.918). Table 4 - Sensitivity, specificity, positive predictive value and negative predictive value of the scoring system proposed using a cut-off of 26 Proposed scale of points In-hospital Mortality Yes No ≥ 26 points 49 134 < 26 points 6 274 Validation measures Percentage value CI (95%) Sensitivity 89.1% 0.809 – 0.973 Specificity 67.2% 0.626 – 0.717 Positive predictive value 26.8% 0.204 – 0.332 Negative predictive value 97.9% 0.962 – 0.996 C Statistic 86.8% 0.818 – 0.918 CI: confidence interval. Table 5 - Relationship between the hematological scoring system and the KILLIP score in predicting mortality among patients with into ST-segment elevation myocardial infarction Scale of points KILLIP Total I and II III and IV ≥ 26 points 120 (40.3%) 23 (82.1%) 143 < 26 points 178 (59.7%) 5 (17.9%) 183 Total 298 28 326 Kappa coefficient = 0.141 (61.5% overall agreement). with poorer prognosis. The scoring system with these three variables, after adjusted multivariate analysis and a cut-off of 26 points, showed a sensitivity of 89.1%, specificity of 67.2%, negative predictive value of 97.9% and positive predictive value of 26.8%. Thus, with these cut-off points on a scale of 0 to 49 points, patients can be categorized into two groups: low and high risk of death, with an accuracy of 86.8% (area under the ROC curve). The main purpose of this hematological scoring system is to promote better clinical surveillance during hospitalization based on these laboratory variables. In addition, results of the score showed an agreement with patients’ clinical data, as the lower risk in-hospital mortality was associated with lower score values. This hematological scoring system had a negative predictive value of 97.9%. Monteiro Júnior et al. Hematological scoring system in AMI Int J Cardiovasc Sci. 2020; 33(4):380-388 Original Article