Work productivity and activity impairment in patients with narcolepsy type 1

The aim of this study was to assess work productivity and activity impairments and to explore their association with excessive daytime sleepiness, body mass index (BMI), depression, and anxiety in patients with narcolepsy type 1. We carried out a cross-sectional study in which patients with narcolepsy type 1 and matched controls for sex, age, and education were assessed for occupational features, EDS (Epworth Sleepiness Scale), BMI, depression (Beck Depression Inventory), anxiety (State-Trait Anxiety Inventory), and Work Productivity and Activity Impairment (WPAI). Different statistical approaches were used to investigate differences between groups and correlations between WPAI scores and clinical features. The 127 patients with narcolepsy type 1 (mean age 38.2 +/- 15.5, 91.3% taking drugs for narcolepsy) and 131 controls (mean age of 37.4 +/- 14.3) included did not differ in terms of occupational features, except for hours worked/week (29.9 in patients vs. 34.9 in controls) and officially recognised disability (30.7% vs. 5.3%). Impairment in all WPAI scores was approximately three times greater in patients. Narcolepsy was associated with work time missed in 27.4% of patients, while 93.2% to 95.5% of them had some impairment while working or during daily activities (vs. 37.5-46.8% of controls). Correlations with WPAI scores were found for excessive daytime sleepiness only in patients, and for both depression and anxiety in patients and controls, with a stronger correlation for activity impairment in patients. These results suggest that, despite treatment, narcolepsy type 1 was associated with extensive impairment especially regarding job effectiveness and daily activities. Future studies should investigate risk factors and effects of interventions on these outcomes.