Comparative evaluation of H&H and WFNS grading scales with modified H&H (sans systemic disease): A study on 1000 patients with subarachnoid hemorrhage

The comparative studies on grading in subarachnoid hemorrhage (SAH) had several limitations such as the unclear grading of Glasgow Coma Scale 15 with neurological deficits in World Federation of Neurosurgical Societies (WFNS), and the inclusion of systemic disease in Hunt and Hess (H&H) scales. Their differential incremental impacts and optimum cut-off values for unfavourable outcome are unsettled. This is a prospective comparison of prognostic impacts of grading schemes to address these issues. SAH patients were assessed using WFNS, H&H (including systemic disease), modified H&H (sans systemic disease) and followed up with Glasgow Outcome Score (GOS) at 3 months. Their performance characteristics were analysed as incremental ordinal variables and different grading scale dichotomies using rank-order correlation, sensitivity, specificity, positive predictive value, negative predictive value, Youden's J and multivariate analyses. A total of 1016 patients were studied. As univariate incremental variable, H&H sans systemic disease had the best negative rank-order correlation coefficient (-0.453) with respect to lower GOS (p < 0.001). As univariate dichotomized category, WFNS grades 3-5 had the best performance index of 0.39 to suggest unfavourable GOS with a specificity of 89% and sensitivity of 51%. In multivariate incremental analysis, H&H sans systemic disease had the greatest adjusted incremental impact of 0.72 (95% confidence interval (CI) 0.54-0.91) against a lower GOS as compared to 0.6 (95% CI 0.45-0.74) and 0.55 (95% CI 0.42-0.68) for H&H and WFNS grades, respectively. In multivariate categorical analysis, H&H grades 4-5 sans systemic disease had the greatest impact on unfavourable GOS with an adjusted odds ratio of 6.06 (95% CI 3.94-9.32). To conclude, H&H grading sans systemic disease had the greatest impact on unfavourable GOS. Though systemic disease is an important prognostic factor, it should be considered distinctly from grading. Appropriate cut-off values suggesting unfavourable outcome for H&H and WFNS were 4-5 and 3-5, respectively, indicating the importance of neurological deficits in addition to level of consciousness.