Evaluation of Two Fatigability Severity Measures in Elderly Adults

Authors

  • John F. Schnelle PhD,

    Corresponding author
    1. Geriatric Research, Education and Clinical Center, Veterans Affairs Medical Center, Nashville, Tennessee
    • Division of General Internal Medicine and Public Health, Center for Quality Aging, Vanderbilt University, Nashville, Tennessee
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  • Maciej S. Buchowski PhD,

    1. Division of Gastroenterology, Hepatology and Nutrition, Energy Balance Laboratory, Vanderbilt University, Nashville, Tennessee
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  • Talat A. Ikizler MD,

    1. Division of Nephrology, Department of Medicine, School of Medicine, Vanderbilt University, Nashville, Tennessee
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  • Daniel W. Durkin PhD,

    1. Division of General Internal Medicine and Public Health, Center for Quality Aging, Vanderbilt University, Nashville, Tennessee
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  • Linda Beuscher PhD,

    1. Division of General Internal Medicine and Public Health, Center for Quality Aging, Vanderbilt University, Nashville, Tennessee
    2. School of Nursing, Vanderbilt University, Nashville, Tennessee
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  • Sandra F. Simmons PhD

    1. Division of General Internal Medicine and Public Health, Center for Quality Aging, Vanderbilt University, Nashville, Tennessee
    2. Geriatric Research, Education and Clinical Center, Veterans Affairs Medical Center, Nashville, Tennessee
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Address correspondence to John F. Schnelle, Vanderbilt University, 2525 West End Avenue, Suite 350, Nashville, TN 37203. E-mail: john.schnelle@vanderbilt.edu

Abstract

Objectives

To document the stability, concurrent validity, and clinical correlates of two fatigability severity measures as recommended by the American Geriatrics Society.

Design

Descriptive, cross-sectional.

Setting

Two independent living and one community senior centers.

Participants

Forty-three participants, with an average age 85 ± 6.

Measurements

Perceived fatigability severity was quantified by directly asking participants to report change in energy after a standardized 10-minute walk at a self-selected pace. Performance fatigability severity was defined as a ratio of change in walking speed to total distance walked. The walk test was repeated within 2 weeks to assess stability. Total daily physical activity (PA) was measured over 7 consecutive days using a waist-worn accelerometer. Frailty was measured using the Vulnerable Elders Survey interview scale, and gait speed was measured using a standardized 25-feet walk test.

Results

The perceived and performance fatigability severity measures were significantly correlated (correlation coefficient (r) = 0.94, P < .001) and stable over two assessments (r = 0.82 and 0.85, P < .001). Both fatigability severity measures were significantly correlated with PA level (r = −0.42 and r = −0.44, respectively, P = .02), frailty (r = 0.47 and 0.53, respectively, P = .001) and gait speed (r = −0.45, P = .003 and r = −0.54, P = .001, respectively).

Conclusion

The methodology described in this study permits the calculation of two highly correlated fatigability severity scores, which summarize the relationship between a person's change in self-reported tiredness or change in physical performance and concurrently measured PA. The fatigability severity scores are reproducible and correlated with clinical measures predictive of decline. The methods used to quantify fatigability severity can be implemented during a brief assessment (<15 minutes) and should be useful in the design and evaluation of interventions to increase PA in older adults at risk of functional decline.

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