Convergent validity and reproducibility of the International classification of functioning, disability and health (ICF) core set for the physical health of community-dwelling older adults

Abstract Background Physical health is an important factor for what is considered successful aging. Using valid and reproductible tools to classify PH of older adults may help to develop appropriate rehabilitation protocols for this population. Objective To evaluate the convergent validity and reproducibility of the International Classification of Functioning, Disability and Health (ICF) core set to classify the physical health of older adults. Methods A total of 101 older adults were evaluated for handgrip strength, physical performance (Short Physical Performance Battery), and physical activity level (International Physical Activity Questionnaire). Physical health was classified with the ICF core set (14 categories of body functions, 4 of body structures, 9 of activity and participation, and 3 environmental factors) and an impairment index was calculated for each component. Results Higher levels of physical activity were associated to lower impairment index in the body function and activity and participation components, but was not associated to environmental factors. Better physical performance and handgrip strength were also related to lower impairment index in all components. The Intraclass Correlation Coefficient analysis indicated good reproducibility for body function, body structure, the capacity component of the activity and participation, and for two environmental factors (use of medications and assistive devices), but moderate reproducibility for the performance component of activity and participation, and poor reproducibility for the environmental factor related to access to health services. Conclusion The ICF core set for the physical health of older adults is a valid and reproducible tool and can be used in clinical practice and research.