Dependence scale for Alzheimer's disease: relationship with other clinical indicators and psychometric properties

The objective of this cross-sectional and multicenter study was to evaluate the psychometric properties of the Spanish version of the Dependence Scale (DS) and to assess the relationship between dependence and clinical measures according to disease severity. Medical comorbidities, cognitive status and functional status, behavior, dependence, caregiver burden, and medical and social resources were assessed using standardized instruments. The sample consisted of 343 patients (32.1% mild, 36.7% moderate, and 31.2% severe), the mean age was 78.9 years (standard deviation=7.4), and 67.0% were women. Criterion and construct validity index of DS were appropriate. The DS standard error of measurement was ±1.23. The explained variance in DS ranged between 0.598 and 0.731, and the relative contribution of clinical measures depended on disease severity. Current findings confirm that the Spanish version of the DS has appropriate psychometric indices and suggest that clinical indicators have different contribution to dependence according to disease severity.