Assessment of Geriatric Depression Scale's Applicability in Longevous Persons based on Classical Test and Item Response Theory.
Academic Article
Overview
abstract
BACKGROUND: The 15-item short form Geriatric Depression Scale (GDS-15) has been widely used for depression screening in multiple settings. However, few studies have specifically investigated the applicability of GDS-15 in longevous population. The aim of this study is to evaluate the psychometric property and item characteristic of the scale in Chinese community-dwelling longevous persons. MATERIALS AND METHODS: A total of 838 longevous people participated in this study. The reliability and validity of GDS-15 were analyzed with classical test theory, and the characteristics of each item were analyzed with item response theory using a three-parameters logistic model. RESULTS: The Cronbach's α coefficient of the scale was 0.776. Spearman correlation coefficients between the GDS-15 score and each item were between 0.274 and 0.667 (P<0.01); the summed GDS-15 score was negatively associated with physical function, self-report health status and subjective well-being. Factors extracted using exploratory factor analysis accounted for 52.63% of the variance and the item loadings were between 0.513 and 0.828. The discrimination of each item ranged from 1.045 to 3.777; the difficulty ranged from -0.972 to 2.006, and the guessing parameter ranged from 0.000 to 0.499. The total information of GDS-15 was 13.645 when the subject's latent trait located at 1.131. LIMITATION: The sample used is representative of the longevous in rural communities, thus extrapolation to other populations requires further validation. CONCLUSION: The GDS-15 has good applicability in depression detecting among Chinese longevous persons, especially for the individuals with moderate symptoms. Suggestions were provided on further improving its measurement precision.
