Interobserver variability of grading scales for aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE Worldwide, different scales are used to assess the clinical condition on admission after aneurysmal subarachnoid hemorrhage. In addition to the prognostic value, the inter-rater variability should be taken into account when deciding which scale preferably should be used. We assessed the interobserver agreement of the commonly used World Federation of Neurological Surgeons, the Hunt and Hess, and the Prognosis on Admission of Aneurysmal Subarachnoid Hemorrhage scales. METHODS In a cohort of 50 subarachnoid hemorrhage patients, 103 paired assessments were performed on the 3 admission scales by 2 independent observers per assessment with a total of 57 different raters. Patients were assessed during the first week after the hemorrhage. The interobserver agreement was calculated using quadratic (weighted) kappa statistics. RESULTS The weighted kappa value of the Prognosis on Admission of Aneurysmal Subarachnoid Hemorrhage scale was 0.64 (95% CI, 0.49-0.79), of the World Federation of Neurological Surgeons scale was 0.60 (95% CI, 0.48-0.73), and of the Hunt and Hess scale was 0.48 (95% CI, 0.36-0.59). CONCLUSIONS The Hunt and Hess scale showed the lowest interobserver agreement, whereas agreement of the World Federation of Neurological Surgeons and Prognosis on Admission of Aneurysmal Subarachnoid Hemorrhage scales was similar with overlapping CI.