Druce KL, et al. - Experts tested the presumption that the prevalent symptom of fatigue longitudinally forecasts work disability among rheumatoid arthritis (RA) and ankylosing spondylitis (AS) patients starting etanercept. Findings suggested a significant and independent impact of fatigue on absenteeism, presenteeism, productivity loss, and activity impairment for RA patients among those beginning etanercept therapy. Among AS patients, fatigue was significantly linked to presenteeism and activity impairment.