[Functional independence in daily activities-Validation of the FIDA assessment in rehabilitated geriatric patients].

Background: The Functional Independence in Daily Activities (FIDA) is an assessment with 20 items to measure functional independence in activities of daily living. Each item uses a 5-point scale to assess how independently the person can perform the described function. The grading ranges from 'independent/ability present' to 'dependent/ability absent'.

Material and methods: 1593 rehabilitants were included in the study. The FIDA and Barthel Index (BI) assessments were used to measure functional independence at the beginning and at the end of rehabilitation. Item difficulty, discriminatory power (r_it = item total correlation) and internal consistency (Cronbach's α) were calculated. The factor structure was tested using a confirmatory factor analysis. Convergent validity was tested by correlating the sum values of the FIDA and the BI.

Results: The item difficulties (p_i) were in the range between 0.17 ≤ p_i ≤ 0.89. The internal consistency was α = 0.94 with item-scale correlations between 0.45 < r_it < 0.80. The agreement between FIDA and BI at the start of rehabilitation was r = 0.75. The standardised comparison of the sensitivity to change showed slight advantages for the FIDA. The functional areas that were more severely impaired at the start of rehabilitation showed greater improvements.

Conclusion: The FIDA is a change-sensitive assessment instrument that is suitable for assessing functional independence in geriatric patients. The psychometrics and analyses on the validity showed good results.