Introduction

Narcolepsy is a chronic sleep disorder with multiple comorbid conditions. Sodium oxybate (SXB) is strongly recommended for treatment of narcolepsy. This study used aggregate electronic health record (EHR) data to characterize demographic characteristics and comorbidities of patients with narcolepsy treated with or without SXB.

Methods

An EHR-based search identified first-time Mayo Clinic patients between 1975–2020. Patients had ≥1 narcolepsy-specific ICD-9/-10 code and ≥1 diagnostic mention of narcolepsy in clinical notes (natural-language-processing algorithm). Patients with narcolepsy treated with SXB were age/sex matched with a cohort without SXB treatment. Common comorbidities were identified using ICD-9/-10 codes and compared between cohorts (odds ratio [OR]).

Results

Of 4387 patients identified, 8% received SXB treatment (n=351; mean [IQR] age at first diagnosis code observed at Mayo Clinic, 32 [23.2-46.1] y; 65.5% female; 92.3% white); 4036 patients had no SXB treatment (mean [IQR] age at first diagnosis code observed at Mayo Clinic, 44.8 [29.8-59.0] y; 58.0% female; 88.9% white). The 10 most commonly reported comorbidities (overall population) were insomnia (46.6%), fatigue (46.3%), depression (42.2%), hypertension (36.2%), hyperlipidemia (34.2%), obstructive sleep apnea (32.3%), diabetes mellitus (31.3%), arrhythmia (27.3%), idiopathic hypersomnia (IH; 26.8%), and coronary artery disease (17.6%). A cohort of 351 patients without SXB were age/sex matched to patients with SXB for comparison of comorbidities. In the unadjusted analysis, P values were significant for differences between cohorts (OR [95% CI] SXB vs no SXB) for fatigue (0.72 [0.54-0.97]; P< 0.05; adjusted P>0.9) and IH (0.60 [0.43-0.84]; P< 0.01; adjusted P=0.29). After P value adjustment (Bonferroni correction), there were no significant differences between these cohorts in ORs for any comorbidity. The matched cohorts, which were younger than the overall population, had numerically lower rates of these diagnoses vs the overall population, except fatigue and IH in patients without SXB and depression in patients with SXB.

Conclusion

Among age-/gender-matched cohorts of patients with/ without SXB, there were no significant differences in comorbidities. Prevalence of comorbid IH/narcolepsy diagnoses highlight the diagnostic challenge in differentiating IH from narcolepsy type 2. SXB is highly effective but used by < 1:10 patients with narcolepsy in the Mayo Clinic health system.

Support (if any)

Avadel Pharmaceuticals