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.