Introduction Excessive daytime sleepiness (EDS) is disabling and it’s control is usually contingent on ongoing pharmacological therapy including: modafinil, methylphenidate, dexamfetamine, pitolisant, and sodium oxybate. Irrespective of the medication used, all pharmacological options must be taken to have an effect and while assessment of treatment adherence is standard clinical practice in many chronic conditions, in sleep medicine, evidence regarding adherence to prescribed medications is strikingly limited.

The aim of this study was to assess degree and predictors of adherence to prescribed treatment in patients with narcolepsy attending a tertiary Sleep Disorders Centre.

Methods We examined adherence to treatment in consecutive adult patients with a final diagnosis of narcolepsy by comparing prescription collection rates with prescribed therapy over a one-year period. Three levels of adherence were defined depending on the medication supplied in the last year in proportion to the total prescribed: poor (≤50%), intermediate (51–79%), and good (≥80%) adherence. Patients with adherence <80% were considered as sub-optimally adherent.

Results Demographic and clinical characteristics 162 patients were identified, from which 123 subjects with accurate information regarding current treatment regimen and adherence were included (see table 1). Good adherence was seen in 52.8% of patients, whilst 12.2% were intermediately and 35% poorly adherent. No difference was seen in proportion of good adherence between patients with refractory vs non-refractory symptoms (41.5% vs 58.5%; p=0.68). The proportion of refractory patients with suboptimal adherence was 44.9%. Patients with NT1 were less likely than those with NT2 to have suboptimal adherence (40.4% vs 75%; p=0.002).

Discussion Our findings suggest that poor adherence is observed in a high proportion of patients with narcolepsy, and that a diagnosis of NT2 seems to be associated with non-adherence to prescribed treatment. Adherence to treatment should be routinely assessed in narcolepsy, particularly prior to initiating any step-up in therapy.