Measuring subclinical disability in older Mexican Americans

Objective: The purpose of this study was to develop a comprehensive list of adaptive strategies to prevent disability and use this information to devise a preliminary measure of subclinical disability (state of sustained independence in the presence of latent or manifest functional limitations) suitable for older Mexican Americans. Method: Semistructured interviews were conducted with 24 community-dwelling Mexican American elders ( greater than or equal to65 years old) to elicit information about adaptations in performance of daily living tasks (eg, walking, dressing, and shopping) that may indicate presence of subclinical disability. This information was used to construct a quantitative self-report measure of subclinical disability administered to 207 older Mexican Americans. Item and factor analyses were performed to reduce the number of items and establish their underlying structure. Construct and discriminant validity of the reduced instrument was determined. Results: A framework comprised of nine categories of daily living tasks, three functional levels, and five adaptation types was generated from the qualitative data. The initial 133-item measure (named the ADAPT) was reduced to a 44-item scale with three subscales (physical, household, and social). ADAPT scores correlated significantly in the expected direction with standard functional status measures, but the shared variance was modest, indicating that the ADAPT captured substantial, unique variance. Mean ADAPT scores differed significantly and were monotonically lower across subgroups classified as independent, subclinically disabled, and disabled, respectively. Conclusions: The ADAPT seems to have construct and discriminant validity as a measure of subclinical disability. Additional research is required to determine sensitivity to change and clinically significant cut points for varying risk of frank disability.