Changes in quality of life in individuals with narcolepsy type 1 after the H1N1-influenza epidemic and vaccination campaign in Norway: a two-year prospective cohort study.

OBJECTIVE:Cross-sectional studies show a lower health-related quality of life (HRQoL) in individuals with narcolepsy. We aimed to describe changes in HRQoL after two years of multidisciplinary follow-up in a cohort of mainly post-H1N1 vaccination narcolepsy type-1 (NT1) patients in Norway. METHODS:Prospective-cohort study. Narcolepsy diagnosis was based on the International Classification of Sleep Disorders (third edition). Psychiatric comorbidity was assessed using the Achenbach System of Empirically Based Assessment (ASEBA). HRQoL was evaluated with the Pediatric Quality of Life Inventory (PedsQL™ Generic Core Scales 4.0) at baseline and follow-up. Mean follow-up time was 20.7 (2.7) months. RESULTS:Thirty one patients (18 females) with NT1, mean age 14.6 (SD = 4.8) years answered questionnaires at baseline and follow-up. On a group level, the PedsQL Total Health Summary score significantly improved by a mean of 5.9 (95%CI = 0.4, 11.9), p = 0.038; this was mainly driven by improvements in the Physical Health Summary score by 9.8 (3.0, 16.5) points, p = 0.006 and the School Functioning Scale score by 7.5 (1.0, 13.9) points p = 0.025. The Total ASEBA score was correlated with PedsQL Total Health Summary score at baseline, but not with changes in HRQoL. Sodium oxybate (Xyrem®) treatment at follow up was positively associated with changes in PedsQL Total Health Summary score, after adjusting for age and gender, p = 0.027. CONCLUSION:HRQoL in NT1 patients improved after two years of follow-up. The use of sodium oxybate (Xyrem®) at follow-up was associated with increases in HRQoL. Psychiatric comorbidity was correlated with HRQoL at baseline but did not predict changes in HRQoL at follow-up.