Fatigue and depression predict quality of life in patients with early multiple sclerosis: a longitudinal study

Background and purpose : The clinical predictors of health-related quality of life (HRQoL) in multiple sclerosis (MS) have mainly been studied in patients with long-standing disease. The objective of this study was to investigate the longitudinal association among HRQoL and clinical characteristics in early MS. Methods : Relapsing MS patients within 12 months of clinical onset were enrolled in a neuroprotection trial of riluzole versus placebo as an add-on to weekly interferon with up to 36 months of follow-up. Serial clinical measures included Short Form-36 (SF-36) as the measure of HRQoL, MS Functional Composite (as a measure of disability), Modified Fatigue Impact Scale, Patient Health Questionnaire-9 (as a measure of depression) and a cognitive battery. Multivariable linear regression analyses assessed cross-sectional associations. Mixed model regressions with mutual adjustments were used to assess the longitudinal association of HRQoL components and clinical, cognitive and demographic variables. Results : Forty-three patients were enrolled within 7.5 ± 4.9 months of clinical onset (72% female, mean age 36 years). The baseline severity of fatigue and depression predicted subsequent changes in SF-36 Physical Component Summary (PCS) (P values of 0.001 and 0.021, respectively). In longitudinal analyses, changes in disability and depression were associated with changes in SF-36 PCS (P values of 0.002 and 0.009, respectively), whereas changes in cognitive function and fatigue were associated with changes in SF-36 Mental Component Summary (P values of 0.037 and 0.001, respectively). A 1-unit increase in MS Functional Composite was associated with a 7.1-point increase in SF-36 PCS (95% CI, 2.6–11.6). Conclusions : Fatigue, depression, cognition and disability are independently associated with HRQoL in early MS.