Oxfordshire community stroke project classification improves prediction of post-thrombolysis symptomatic intracerebral hemorrhage

Background The Oxfordshire Community Stroke Project (OCSP) classification is a simple stroke classification system with value in predicting clinical outcomes. We investigated whether and how the addition of OCSP classification to the Safe Implementation of Thrombolysis in Stroke (SITS) symptomatic intracerebral hemorrhage (SICH) risk score improved the predictive performance. Methods We constructed an extended risk score by adding an OCSP component, which assigns 3 points for total anterior circulation infarcts, 0 point for partial anterior circulation infarcts or lacunar infarcts. Patients with posterior circulation infarcts were assigned an extended risk score of zero. We analyzed prospectively collected data from 4 hospitals to compare the predictive performance between the original and the extended scores, using area under the receiver operating characteristic curve (AUC) and net reclassification improvement (NRI). Results In a total of 548 patients, the rates of SICH were 7.3% per the National Institute of Neurological Diseases and Stroke (NINDS) definition, 5.3% per the European-Australasian Cooperative Acute Stroke Study (ECASS) II, and 3.5% per the SITS-Monitoring Study (SITS-MOST). Both scores effectively predicted SICH across all three definitions. The extended score had a higher AUC for SICH per NINDS (0.704 versus 0.624, P = 0.015) and per ECASS II (0.703 versus 0.612, P = 0.016) compared with the SITS SICH risk score. NRI for the extended risk score was 22.3% (P = 0.011) for SICH per NINDS, 21.2% (P = 0.018) per ECASS II, and 24.5% (P = 0.024) per SITS-MOST. Conclusions Incorporation of the OCSP classification into the SITS SICH risk score improves risk prediction for post-thrombolysis SICH.