The European Portuguese Version of the Composite Physical Function Scale: Cross-Cultural Adaptation and Validation in Community-Dwelling Older Adults

This study aims to perform the cross-cultural adaptation to European Portuguese of the Composite Physical Function Scale and to assess its validity and reliability in a sample of community-dwelling older adults. The scale was translated into European Portuguese, back translated, and piloted in a sample of 16 representative individuals. Its validity and reliability were tested in an independent sample of 114 community-dwelling older adults (52 were tested twice to assess test-retest reliability). The results showed that the scale had good internal consistency (alpha = .90), construct validity (rho = .71) and measurement error (78.8% agreement), and excellent test-retest reliability (kappa = .98). However, a ceiling effect was found as 28% of the participants achieved the highest possible score. Although the scale has good measurement properties, the presence of ceiling effects is indicative that this tool is not able to distinguish higher levels of intrinsic capacity within community-dwelling older adults.