Evaluating the reliability and validity of the geriatric assessment of disability scale in older adults undergoing hemodialysis

Abstract

Abstract Background Nearly 50% of patients undergoing maintenance hemodialysis are aged ≥ 60 years, highlighting a growing population with unique health challenges. This study aimed to evaluate the reliability and validity of a functional impairment screening tool for older adults undergoing maintenance hemodialysis. Methods Convenience sampling was used to investigate 283 older adults (160 men and 123 women) undergoing maintenance hemodialysis across four hemodialysis centers. The reliability and validity of the Functional Impairment Screening Tool were evaluated using psychometric indices: Cronbach's α to assess internal consistency, split-half reliability to determine scale consistency, factorial analysis to inspect construct validity, and correlation with the Barthel Index as a comparator measure for criterion validity. Results The screening tool comprised three dimensions and 16 items. Exploratory factor analysis revealed two common factors with eigenvalues > 1, explaining 80.49% of the cumulative variance. The factor-loading range across all items varied from 0.702–0.860. The tool demonstrated 100% acceptance and qualification rates. The Cronbach's α coefficient was 0.940, indicating excellent internal consistency. When analyzed by dimension, Cronbach's α coefficients were 0.940 for personal life, 0.928 for family life, and 0.948 for social activity function. Split-half reliability, as measured by the Spearman–Brown coefficient, was 0.940 for the overall scale, with corresponding coefficients of 0.943, 0.891, and 0.947 for personal life, family life, and social activity functions, respectively. Additionally, the Guttman split-half coefficient was 0.920 for the overall scale, ranging from 0.929–0.877 across dimensions. Finally, the Spearman rank correlation coefficient between the total score of the functional impairment screening scale and the Barthel Index, as a measure of convergent validity, was r = 0.886 (P < 0.001), indicating a strong positive relationship. Conclusions These findings showcase that the Functional Impairment Screening Tool scale demonstrated strong reliability and validity, implying its suitability for evaluating daily functioning in older adults undergoing maintenance hemodialysis.

Keywords

• Hemodialysis
• Older adults
• Functional impairment assessment scale
• Reliability
• Validity