Giving meaning to measure: linking self-reported fatigue and function to performance of everyday activities.
Fatigue, a common symptom of cancer patients, particularly those on active treatment, is generally evaluated using self-report methods, yet it remains unclear how self-reported fatigue scores relate to performance of daily activities. This study examines the relationships among self-reported and performance-based measures of function in patients receiving chemotherapy (CT) to link self-reported fatigue measures to self-report and performance-based measures of function. Self-reported fatigue using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and self-reported physical function using the physical function 10 subscale of the Short Form 36 (SF-36) (PF-10) were measured in 64 patients within 2 weeks of beginning CT (n=64) and after three cycles of CT (n=48). Motor and cognitive functions were captured using five self-reported and seven observed-performance measures at each time point. Significant correlations between self-reported and observed measures ranged from 0.30 to 0.71. Self-reported fatigue correlated (0.30-0.45) with performance-based function. FACIT-F scores in the range of 30 and below and PF-10 scores in the range of 50 and below were related to an increased difficulty performing everyday activities. Observed measures of physical performance correlate moderately with self-reported fatigue and self-reported physical function. These relationships enable one to begin linking fatigue scores directly to a person's ability to perform everyday activities.
Rehabilitation Institute of Chicago and Northwestern University, Chicago, Illinois 60611, USA. trudy@northwestern.edu
Trudy
T
Mallinson
David
D
Cella
John
J
Cashy
Bernhard
B
Holzner
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D003071:Cognition / Q000502:physiology; D005221:Fatigue / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009369:Neoplasms / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology*; D012647:Self-Assessment