External validation of the nag scale for predicting hematoma expansion in patients with acute intracerebral hemorrhage

Abstract

Early hematoma expansion (HE) is seen in about 30% of intracerebral hemorrhage (ICH) patients, but detecting high risk factors for HE is challenging. The NAG scale was one of the proposing factors for HE in patients with acute ICH. The aim of this study is to validate the scale. Between January 2016 and December 2018, we retrospectively reviewed consecutive series of patients with primary ICH, who were diagnosed by an initial non-contrast computed tomography (CT) scan within 24 h after onset. Patients underwent follow-up CT scans at 6 h, 24 h, and 7 days after admission, and the HE was defined as an increasing rate in hematoma volume >33% or an absolute volume of increment >6 mL on follow-up CT scans, compared with initial CT scans. Poor prognosis was defined as modified Rankin Scale 4–6 at discharge. Logistic regression analysis and receiver operating characteristic curves were used to determine discrimination ability of the score. A total of 82 patients (51 men; median age 67 years) were analysed in our study, and HE was included in 25 patients (30%). Higher NAG sores were related to HE, poor prognosis, and in-hospital death. The C statistic was 0.77 (95% confidence interval [CI], 0.66–0.88) for HE, 0.77 (95% CI, 0.67–0.87) for poor prognosis, and 0.80 (95% CI, 0.68–0.92) for in-hospital death. Multivariate logistic regression analysis with known risk factors showed the NAG scale was the sole predictor for HE. External validation of the NAG scale showed good discrimination.