Abstract
STUDY OBJECTIVES: Idiopathic hypersomnia (IH) is a disorder of central hypersomnolence that results in excessive daytime sleepiness in the absence of another identifying cause. Case studies from sleep clinic patients may not be a fair representation of the wider IH population. This study aims to better characterize patients diagnosed with IH in Australia and New Zealand using online patient-driven survey data. METHODS: A retrospective analysis of 686 participants from the Hypersomnolence Australia Patient Data Registry diagnosed with either IH (n = 554), narcolepsy type 1 (n = 54), or narcolepsy type 2 (n = 78) between January 2013 and October 2022 was performed. RESULTS: Participants with IH reported additional sleep disorders such as obstructive sleep apnea (16.4%) and restless legs syndrome (7.9%), and notable comorbidities included depression (46.2%) and anxiety (50%). There was a mean delay in diagnosis of 10 years in participants with IH, when compared to symptom onset. IH presents with unique but also overlapping symptomatology with narcolepsy type 2, with similar reporting of long daytime naps, unrefreshed sleep, and automatic behavior. Modafinil was the most common medication (45.5%) used by participants with IH, followed by dexamphetamine (44.2%). Most participants with IH reported receiving physicians' advice regarding positive lifestyle changes but recommend that newly diagnosed patients be given more advice about medication use. CONCLUSIONS: This study demonstrates a delay in IH diagnosis when compared to symptom onset and overlapping features of IH and narcolepsy type 2. It also highlights the heterogeneous presentation of IH and the value of large patient registries in future research. CITATION: Anderson J, Yee BJ, Grunstein R, et al. Insights from a 10-year Australasian idiopathic hypersomnia patient data registry study. J Clin Sleep Med. 2024;20(12):1955-1964.