Factors associated with diagnostic delay in narcolepsy: Real-world data from a Korean multicenter study

Narcolepsy is a rare chronic neurological disorder characterized by a pentad of symptoms: excessive daytime sleepiness, cataplexy, hypnagogic hallucination, sleep paralysis, and disturbed nighttime sleep. Narcolepsy begins in children and adolescents, yet most patients experience a diagnostic delay. We investigated this diagnostic delay and the factors contributing to it in Korean narcolepsy patients.

We retrospectively analyzed real-world, multi-center data from 137 patients with narcolepsy from 11 tertiary hospitals in South Korea. Demographic and clinical characteristics, polysomnography, and multiple sleep latency test data were available.

The mean age at first symptom onset and diagnosis was 18.2 ± 8.9 and 28.3 ± 13.3 years, respectively. Mean and median diagnostic delay were 10.3 ± 11.3 and 7.0 (3.0-13.0) years. In multivariable regression analysis, shorter sleep duration on holiday (β = - 0.75, p = 0.040), lower sleep efficiency (β = - 0.39, p = 0.011), reduced N2 sleep (β = - 0.17, p = 0.045), and lower nadir SpO₂ (β = - 0.67, p = 0.013) emerged as associated factors of prolonged diagnostic delays.

The diagnostic delay for narcolepsy remains long and is related to shorter sleep duration during the holiday, and poor objective nocturnal sleep. Shortening this diagnostic delay is the key to reducing disease burden and improving quality of life. This study highlights the importance of directing advocacy and educational efforts toward narcolepsy awareness.