Combined Idiopathic Intracranial Hypertension score, an integrated severity and treatment-oriented tool for idiopathic intracranial hypertension: a retrospective cohort study

Abstract

IIH has evolved into a multidisciplinary condition managed across neurology, ophthalmology, interventional neuroradiology, and surgery. Existing tools address only partial aspects of disease severity; no unified, treatment-oriented classification exists to support multidisciplinary decision-making. Cross-specialty communication is inconsistent leading to heterogenous therapeutic decisions. We aimed to develop and evaluate a standardized multidisciplinary score for idiopathic intracranial hypertension (IIH) and assess its association with therapeutic escalation. We enrolled adults fulfilling the revised Friedman criteria at a tertiary interventional neuroradiology referral center from 2020 to 2025. Clinical data were organized into four domains: ophthalmologic severity with a combination of visual function and tomographic data (E grades 1–4), neuroradiology findings (N grade A to C), intracranial pressure (ICP), and treatment modality. We included 250 patients (93.0% female, median age at diagnosis 29.0 years, median ICP 34.0 cmH 2 O). E grade was significantly associated with invasive intervention ( p < 0.001 for endovascular stenting, Cochran-Armitage test for trend). Among E1-grade patients, 64% underwent endovascular stenting and 64% received high-dose methylprednisolone. Firth’s penalized logistic regression confirmed E grade as a significant independent predictor of invasive interventions (adjusted odds ratio = 0.47 per grade [toward milder disease]; 95% CI 0.32–0.68, p < 0.001). Inter-rater agreement for E grading was substantial (weighted Cohen’s κ 0.82, 95% CI 0.68–0.96). The Combined Idiopathic Intracranial Hypertension score provides a shared, notation for multidisciplinary IIH documentation. In this cohort, the ophthalmologic grade and intracranial pressure were associated with the need for invasive intervention (adjusted OR 0.47 per grade toward milder disease; AUC 0.68), and E grading showed substantial inter-rater agreement (weighted κ 0.82). Prospective external validation is required before the complete four-domain score can be recommended for clinical decision-making. Not applicable.