Obstructive sleep apnea and idiopathic intracranial hypertension: a systematic review and meta-analysis.

OBJECTIVE: To determine the pooled prevalence of obstructive sleep apnea (OSA) among adults with idiopathic intracranial hypertension (IIH) using polysomnography (PSG) and the Berlin Questionnaire screening. NATURE: IIH is a vision-threatening disorder characterized by elevated intracranial pressure. OSA shares overlapping risk factors and pathophysiological mechanisms with IIH, including nocturnal hypoxia and hypercapnia. Clarifying OSA prevalence in IIH is clinically important for diagnosis and management. METHODS: For this prospectively registered systematic review and meta-analysis (PROSPERO: CRD420251132794), we searched MEDLINE, Embase, and CENTRAL from inception to August 23, 2025, for studies reporting PSG-confirmed OSA or Berlin Questionnaire positivity in adults with IIH. Risk of bias was assessed using ROBINS-I and RoB-2, and certainty of evidence was checked using the Grading of Recommendations, Assessment, Development and Evaluation tool. Random-effects meta-analyses of proportions generated pooled prevalence estimates. Subgroup analyses excluded high-risk studies, leave-one-out analyses assessed robustness, and funnel plots evaluated publication bias. RESULTS: Eleven studies met the inclusion criteria. Across 9 PSG-based studies (n = 299), the pooled prevalence of OSA in IIH was 0.44 (95% CI: 0.26-0.63; I² = 90.5%). Leave-one-out analyses showed stable results (39%-50%). Excluding high-risk studies (4 studies; n = 132) yielded a pooled prevalence of 0.53 (95% CI: 0.32-0.74). Four Berlin Questionnaire studies (n = 154) showed a pooled prevalence of 0.65 (95% CI: 0.54-0.74; I² = 0%). Funnel plot asymmetry suggested publication bias, and certainty of evidence was very low. CONCLUSIONS: OSA is common among patients with IIH, supporting routine objective sleep evaluation. Prospective studies are needed to clarify this association.