Background: Fatigue affects 33-77% of stroke survivors. There is no consensus concerning risk factors for fatigue post-stroke, perhaps reflecting the multifaceted nature of fatigue. We characterized post-stroke fatigue using the Fatigue Impact Scale (FIS), a validated questionnaire capturing physical, cognitive, and psychosocial aspects of fatigue.
Methods: The Stroke Outcomes Study (SOS) prospectively enrolled ischemic stroke patients from 2001-2002. Measures collected included basic demographics, pre-morbid function (Oxford Handicap Scale, OHS), stroke severity (Stroke Severity Scale, SSS), stroke subtype (Oxfordshire Community Stroke Project Classification, OCSP), and discharge function (OHS; Barthel Index, BI). An interview was performed at 12 months evaluating function (BI; Modified Rankin Score, mRS), quality of life (Reintegration into Normal living Scale, RNL), depression (Geriatric Depression Scale, GDS), and fatigue (FIS).
Results: We enrolled 522 ischemic stroke patients and 228 (57.6%) survivors completed one-year follow-up. In total, 36.8% endorsed fatigue (59.5% rated one of worst post-stroke symptoms). Linear regression demonstrated younger age was associated with increased fatigue frequency (β=-0.20;p=0.01), duration (β=-0.22;p<0.01), and disability (β=-0.24;p<0.01). Younger patients were more likely to describe fatigue as one of the worst symptoms post-stroke (β=-0.24;p=0.001). Younger patients experienced greater impact on cognitive (β=-0.27;p<0.05) and psychosocial (β=-0.27;p<0.05) function due to fatigue. Fatigue was correlated with depressive symptoms and diminished quality of life. Fatigue occurred without depression as 49.0% of respondents with fatigue as one of their worst symptoms did not have an elevated GDS.
Conclusions: Age was the only consistent predictor of fatigue severity at one year. Younger participants experienced increased cognitive and psychosocial fatigue.