Predictive value of the early modified National Institutes of Health Stroke Scale for the prognosis of ischemic stroke / 中华神经科杂志

ABSTRACT

Objective To investigate the predictive value of the modified National Institutes of Health Stroke Scale ( mNIHSS),measured within 9 days after stroke,for the outcome in terms of modified Rankin Scale (mRS) at 6 months after stroke.Methods AII 161 patients with acute anterior circulation ischemic stroke were recruited consecutively from July 2010 until November 2010.The mNIHSS score was assessed within 3 days,4 to 6 days and 7 to 9 days after stroke,and the mRS score at 6 months after stroke was assessed by a neurology resident.Spearman rank correlation and ROC curve were used for statistic analysis.Results One hundred and sixty-one patients were assessed within 3 days,at 4 to 6 days and 7 to 9 days after stroke.Significant Spearman rank correlation coefficients were found between mRS at 6 months and mNIHSS scores within 3 days (rs =0.592,P＜0.01 ),4 to 6 days (rs =0.597,P＜0.01 ) and 7 to 9days (rs =0.595,P＜0.01).At 6 months after stroke,the AUC ranged from 0.789 (95％ CI 0.708-0.856) for measurements within 3 days to 0.792 (95％ CI 0.712-0.857 ) and 0.799 ( 95％ CI 0.721-0.864) for 4 to 6 days and 7 to 9 days,respectively. There was no significant difference for the AUCbetween them.The optimal cut-off values for the prediction of prognosis at 6 months were 8,7 and 6 points of mNIHSS score within 3 days,4 to 6 days and 7 to 9 days,respectively.The negative predictive value gradually increased from 0.847 for assessment within 3 days to 0.867 ( 95％ CI 0.578-0.765 ) for 7 to 9 days,whereas positive predictive value declined from 0.601 for assessment within 3 days to 0.533 for 7 to 9 days.The overall accuracy of predtictions decreased from 0.753 for assessment within 3 days to 0.709 for 7 to 9 days.Conclusions When measured within 9 days,the mNIHSS has a good predictive value for final outcome in terms of mRS at 6 months after stroke.However,the optimal cut-off values for the prediction of prognosis at 6 months are different when early mNIHSS scores were assessed at different periods.