INADEQUACY OF CLINICAL SCORING SYSTEMS TO DIFFERENTIATE STROKE SUBTYPES IN POPULATION-BASED STUDIES

Background and Purpose We undertook to examine the usefulness for epid emiological studies of two well-known validated clinical scoring metho ds, the Guys' Hospital Stroke score and the Siriraj Hospital Stroke sc ore, to classify strokes into the two main types, hemorrhagic and isch emic, in epidemiological studies. Methods Patients from a population-b ased stroke register who received either a CT scan or an autopsy were retrospectively scored using the two clinical scoring methods. The sco res were then compared with the CT scan and autopsy results to determi ne the sensitivity, specificity, and positive predictive value for int racranial hemorrhage (primary intracerebral and subarachnoid hemorrhag e) and ischemic stroke. Results Over a 12-month period, 554 patients f rom a population-based study underwent CT scanning. Films or autopsy r eports were available for 521 patients, and of these, sufficient clini cal information to calculate the Guys' Hospital Stroke score and the S iriraj Hospital Strobe score was available for 464 and 475 patients, r espectively. For the Guys' Hospital Stroke score, the sensitivity and specificity for intracranial hemorrhage were 31% and 95%, respectively ; the positive predictive value was 73%. The sensitivity and specifici ty for ischemic stroke were 78% and 70%, respectively, and the positiv e predictive value was 86%. For the Siriraj Hospital Stroke score, the sensitivity and the specificity for intracranial hemorrhage were 48% and 85%, respectively; the positive predictive value was 59%. The sens itivity and specificity for ischemic stroke were 61% and 74%, respecti vely, and the positive predictive value was 84%. Conclusions This vali dation study suggests that both clinical scores lack sufficient validi ty to be used in epidemiological studies for classification of stroke types and should probably not be used in the randomization of patients into treatment trials using thrombolytic or antithrombotic drugs in t he absence of diagnostic information based on neuroimaging techniques.