Assessing Dependency in a Multiethnic Community Cohort of Individuals With Alzheimer’s Disease

BACKGROUND AND OBJECTIVES: Clinic-based studies of patients with Alzheimer’s disease (AD) have demonstrated the value of assessing dependence when characterizing patients’ functional status. The Dependence Scale, a validated tool to assess level of caregiving needs, is associated with markers of disease severity, cost, and progression, while offering independent functional information about patients. This study examines whether such associations between the Dependence Scale and markers of disease severity demonstrated in clinical cohorts are similarly exhibited in a multiethnic community population of individuals with AD. RESEARCH DESIGN AND METHODS: One hundred fifty four elders with AD enrolled in the Predictors 3 cohort were assessed with the Dependence Scale, modified Mini-Mental State Examination (mMMS), instrumental (IADL) and basic (BADL) activities of daily living, and Clinical Dementia Rating (CDR) Scale, and were assigned an Equivalent Institutional Care (EIC) rating. Cross-sectional associations were examined using bivariate correlations and one-way analysis of variance analyses. Fisher-z tests examined differences in strengths of associations across previous clinic and current community cohorts. RESULTS: Dependence Scale scores were associated with CDR (r = .20, p = .013), mMMS (r = −.23, p = .005), IADL (r = .39, p < .001), BADL (r = .65, p < .001), and EIC (r = .51, p < .001). Dependence was unassociated with ethnicity (F[3,144] = 1.027, p = .3822), age (r = .120, p = .145), and education (r = −.053, p = .519). The strength of the correlations was comparable across cohorts except that BADLs were more strongly associated with dependence (z = −4.60, p < .001) in the community cohort, and living arrangement was not associated with dependence (r = .13, p = .130). DISCUSSION AND IMPLICATIONS: Associations between the Dependence Scale and markers of disease severity in a clinic-based cohort of AD patients are similar to associations in a multiethnic community cohort of individuals diagnosed with AD. The Dependence Scale relates to markers of disease severity rather than demographic factors, and may offer an unbiased assessment of care required in multiethnic and community populations.