title: The Pittsburgh Fatigability scale for older adults: development and validation.
abstract: OBJECTIVE
  To describe the development of the Pittsburgh Fatigability Scale (PFS) and establish its reliability and concurrent and convergent validity against performance measures.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  University of Pittsburgh, Pittsburgh, Pennsylvania.
  
  
  METHODS
  Scale development sample: 1,013 individuals aged 60 and older from two registries; validation sample: 483 adults aged 60 and older from the Baltimore Longitudinal Study of Aging (BLSA).
  
  
  METHODS
  The scale development sample and BLSA participants self-administered an initial 26-item perceived fatigability scale. BLSA participants also completed measures of performance fatigability (perceived exertion from a standard treadmill task and performance deterioration from a fast-paced long-distance corridor walk), a 6-m usual-paced corridor walk, and five timed chair stands.
  
  
  RESULTS
  Principal components analysis with varimax rotation reduced the 26-item scale to the 10-item PFS. The PFS showed strong internal consistency (Cronbach's alpha 0.88) and excellent test-retest reliability (intraclass correlation 0.86). In the validation sample, PFS scores, adjusted for age, sex, and race, were greater for those with high performance fatigability, slow gait speed, worse physical function, and lower fitness, with differences between high and low fatigability ranging from 3.2 to 5.1 points (P < .001).
  
  
  CONCLUSIONS
  The 10-item PFS physical fatigability score is a valid and reliable measure of perceived fatigability in older adults and can serve as an adjunct to performance-based fatigability measures for identifying older adults at risk of mobility limitation in clinical and research settings.
authors.affiliation: Department of Epidemiology, Center for Aging and Population Health, Pittsburgh, Pennsylvania.
authors.forename: Nancy W
authors.initials: NW
authors.lastname: Glynn
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Santanasto
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.forename: Robert M
authors.initials: RM
authors.lastname: Boudreau
authors.forename: Scott R
authors.initials: SR
authors.lastname: Beach
authors.forename: Richard
authors.initials: R
authors.lastname: Schulz
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000375:Aging; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005221:Fatigue / Q000175:diagnosis*; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D010414:Pennsylvania; D005082:Physical Exertion; D016138:Walking / Q000502:physiology
keywords: fatigability; fatigue; mobility; performance measures; validation