Agreement among different fatigue scales in people with extreme longevity and their offsprings: The FACET experience

Fatigue is a symptom frequently complained about by older people but unfortunately poorly understood given its subjectivity and the lack of a gold standard for its assessment. The purpose of this study was therefore to preliminarily explore agreement among four different fatigue scales in a sample of persons with extreme longevity (PEL), their direct offsprings (DO), and controls (CO) matched for age and sex with DO. κ statistics was used to quantify agreement among four different fatigue scales. The agreement ranged from mild to substantial and almost perfect agreement depending on the group considered. The highest agreement was found between the Multidimensional Assessment of Fatigue scale and the Short Form Health Survey-36-Vitality Subscale in the PEL group (κ 0.820; 95 % CI 0.471-0.947). These preliminary findings may serve as a guide in selecting the most feasible instrument to assess fatigue in future large-scale research and clinical activities involving older people.