The Impact of Symptom Severity on Health-Related Quality of Life in Patients with Narcolepsy

Abstract Background: Narcolepsy has deleterious implications on daily life. However, few studies have fully assessed the severity of pentad symptoms of Chinese adults with narcolepsy type 1 (NT1), as well as the relation with health-related quality of life (HRQoL). It is still not clear how the global functioning of patients with NT1 are affected by these pentad symptoms and which does specific symptom affect HRQoL. This is the first study to assess the pentad symptom severity and its correlation with HRQoL in patients with NT1.Methods: Our cross-sectional study is to assess the pentad symptom severity and its correlation with HRQoL in patients with NT1. A total of 174 patients with NT1 were recruited. They completed Narcolepsy Severity Scale (NSS) and European Quality of Life-5 Dimensions Questionnaire (EQ-5D) including five dimensions (EQ-5D utility values) and a visual analog scale (EQ-5D VAS). The relation between severity of symptoms and HRQoL dimensions was assessed by Pearson correlation analyses. Logistic regression was used to identify the significant predictors of HRQoL. Nomogram was established based on results of independent predictors factors on logistic regression analyses. Results: The scores for NSS, EQ-5D utility values and EQ-5D VAS were 29.89±10.08, 0.78±0.09 and 64.30±19.84 in patients with NT1 respectively. NSS score showed a significantly correlation with self-care (r=0.157, P<0.05), usual activities (r=0.236, P<0.01), pain/discomfort (r=0.174, P<0.05), anxiety/depression (r=0.2, P<0.01) and EQ-5D utility values (r=-.261, P<0.01). EDS (excessive daytime sleep), cataplexy, hallucinations, paralysis and disrupted nocturnal sleep (DNS) were significant associated to EQ-5D VAS (r ranged from -0,154 to -0.354, P<0.05). EDS (OR=-0.297, 95% CI -1.892- -0.634) and DNS (OR=-0.16, 95% CI -0.7307- -0.446) were predictors of HRQoL. Regards the NSS scores, NSS score (OR=-0.360, 95% CI -0.979- -0.438) and treated (OR=0.215, 95% CI 3.567-16.188) were predictors of the metrics of HRQoL. The C-indices of the nomogram was 0.726 (95% CI 0.686-0.766). Conclusion: The severity of symptoms could disrupt self-care and usual activities and increase pain/discomfort and anxiety/depression. NSS score could be used for predicting HRQoL, but with a modest precision.