Idling for Decades: A European Study on Risk Factors Associated with the Delay Before a Narcolepsy Diagnosis

Abstract

Purpose Narcolepsy type-1 (NT1) is a rare chronic neurological sleep disorder with excessive daytime sleepiness (EDS) as usual first and cataplexy as pathognomonic symptom. Shortening the NT1 diagnostic delay is the key to reduce disease burden and related low quality of life. Here we investigated the changes of diagnostic delay over the diagnostic years (1990–2018) and the factors associated with the delay in Europe. Patients and Methods We analyzed 580 NT1 patients (male: 325, female: 255) from 12 European countries using the European Narcolepsy Network database. We combined machine learning and linear mixed-effect regression to identify factors associated with the delay. Results The mean age at EDS onset and diagnosis of our patients was 20.9±11.8 (mean ± standard deviation) and 30.5±14.9 years old, respectively. Their mean and median diagnostic delay was 9.7±11.5 and 5.3 (interquartile range: 1.7−13.2 years) years, respectively. We did not find significant differences in the diagnostic delay over years in either the whole dataset or in individual countries, although the delay showed significant differences in various countries. The number of patients with short (≤2-year) and long (≥13-year) diagnostic delay equally increased over decades, suggesting that subgroups of NT1 patients with variable disease progression may co-exist. Younger age at cataplexy onset, longer interval between EDS and cataplexy onsets, lower cataplexy frequency, shorter duration of irresistible daytime sleep, lower daytime REM sleep propensity, and being female are associated with longer diagnostic delay. Conclusion Our findings contrast the results of previous studies reporting shorter delay over time which is confounded by calendar year, because they characterized the changes in diagnostic delay over the symptom onset year. Our study indicates that new strategies such as increasing media attention/awareness and developing new biomarkers are needed to better detect EDS, cataplexy, and changes of nocturnal sleep in narcolepsy, in order to shorten the diagnostic interval.

SPHYNCS: The Use of the Swiss Narcolepsy Scale in a New Cohort of Patients with Narcolepsy and Its Borderland and Review of the Literature

“…The greatest diagnostic delay was seen in individuals with suspected idiopathic hypersomnia (up to 32 years). This confirms previous evidence for delayed diagnosis of CDH and, in particular, narcolepsy, commonly due to physician and patient unawareness of the symptoms characteristic of the disorder [6]. The high sensitivity and specificity of SNS and sSNS scales could significantly prevent delays in the diagnosis of NT1.…”

“…The lack of healthcare awareness regarding narcolepsy hinders both general practitioners and patients from effectively utilizing diagnostic tests to facilitate accurate diagnosis. Consequently, this leads to a significant reduction in the quality of life of affected individuals, secondary psychopathological disturbances, motor vehicle accidents, and financial losses [6,7].…”

Challenges in the Management of Narcolepsy in a Resource Limited Setting: A Case Report

“…Higher CSF orexin levels, the absence of cataplexy, and a prolonged duration of symptoms, that is, pediatric onset of symptoms, have been shown to independently predict a delay in diagnosis [11][12][13]. Other variables linked to a delay in diagnosis include longer intervals between daytime sleepiness and cataplexy onset, lower cataplexy frequency, shorter durations of irresistible daytime sleep, lower daytime REM sleep propensity, and being female [15]. It should be noted that patient-related factors, especially delay in presentation, contribute to the delay in diagnosis.…”

The Swiss Narcolepsy Network (SNaNe)

“…Since there are 7000-8000 rare diseases, with about seven (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) percent of the population concerned, the total number of patients affected by a rare disease in our country is estimated to be more than half a million. Narcolepsy is a rare disease with a suggested prevalence of 1/2000 (data in the literature on the prevalence vary somewhat and we refer to a recent review for details [1]). Patients suffering from narcolepsy share a common fate with patients affected by other rare diseases.…”