Pittsburgh Fatigability Scale: One-Page Predictor of Mobility Decline in Mobility-Intact Older Adults

To evaluate the Pittsburgh Fatigability Scale (PFS) as a predictor of performance and functional decline in mobility-intact older adults.

Longitudinal analysis of Baltimore Longitudinal Study of Aging data.

National Institute on Aging, Clinical Research Unit, Baltimore, Maryland.

Mobility-intact men (46.8%) and women aged 60 to 89 with concurrent PFS administration and performance and functional assessment and follow-up assessment within 1 to 4 years (N=579).

The PFS is a self-administered, 1-page assessment of expected physical and mental fatigue with a score ranging from 0 (no) to 5 (extreme) associated with performing 10 activities. Analyses examined associations between each dimension scored continuously (0-50), categorically (0-5), and dichotomously and change in and likelihood of clinically meaningful decline in usual and fast gait speed, chair stand pace, and reported walking ability. Covariates included age, age² , sex, race, visit status, baseline function, and follow-up time. We defined meaningful decline as 0.05 m/s per year for usual gait speed, 0.07 m/s per year for fast gait speed, 0.02 chair stands/s per year and 1 point or more for walking ability index.

Over a mean 2.2 years, 20.5% to 37.7% of participants experienced meaningful decline across assessments. Independent of covariates, higher PFS physical and mental scores were most consistently associated with greater decline in usual gait speed, chair stand pace, and reported walking ability regardless of scoring approach. For example, higher physical fatigability was associated with twice the likelihood of meaningful decline in gait speed as lower physical fatigability (p=.001). PFS scores were superior to fatigue symptoms such as tiredness and energy level in predicting performance decline, which showed no association.

Routine self-administered perceived fatigability assessment may help identify older persons vulnerable to accelerated mobility decline. J Am Geriatr Soc 66:2092-2096, 2018.