Methodological issues in a cost-of-dementia study in Belgium: the NAtionalDementia Economic Study (NADES)

The NAtional Dementia Economic Study (NADES) is an on-going prospective, on e-year cohort study, developed in Belgium to assess the socio-economic cons equences of dementia in a group of patients and their caregivers (n = 400). Comparison is made with a group of subjects with cognitive impairment and no dementia (n = 100) and a group of subjects without any cognitive impairm ent (n = 100). Recruitment of subjects is based on screening of warning sig ns Of dementia by general practitioners, followed by a Cambridge Mental Dis orders of the Elderly Examination (CAMDEX) performed at home. This paper pr esents an overview of the study, protocol and the rationale for basic desig n options, such as the choice of study population, screening strategy: and methods used for the case validation. It also presents preliminary results on the prevalence of dementia in general practice, the sensitivity and spec ificity, of the warning signs as a screening test of dementia, and the vali dity, of a computerised case ascertainment algorithm based on DSM-III-R cri teria.