Clinical criteria for the diagnosis of vascular dementia: a multicenter study of comparability and interrater reliability.

BACKGROUND: Several clinical criteria have been developed to standardize the diagnosis of vascular dementia (VaD). Significant differences in patient classification have been reported, depending on the criteria used. Few studies have examined interrater reliability.
OBJECTIVE: To assess the concordance in classification and interrater reliability for the following 4 clinical definitions of VaD: the Hachinski Ischemic Score (HIS), the Alzheimer Disease Diagnostic and Treatment Centers (ADDTC), National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN), and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).
METHODS: Structured diagnostic checklists were developed for 4 criteria for VaD, 2 criteria for Alzheimer disease (AD), and 4 criteria for dementia. Twenty-five case vignettes, representing a spectrum of cognitive impairment and subtypes of dementia, were prepared in a standardized clinical format. Concordance in case classification using different criteria and interrater reliability among 7 ADDTCs given a specific set of criteria was assessed using the kappa statistic.
RESULTS: The frequency of a diagnosis of VaD was highest using the modified HIS or DSM-IV criteria, intermediate using the original HIS and ADDTC criteria, and lowest using the NINDS-AIREN criteria. Scores for interrater reliability ranged from kappa = 0.30 (ADDTC) to kappa = 0.61 (original HIS).
CONCLUSIONS: Clinical criteria for VaD are not interchangeable. Depending on the criteria selected, the reported prevalence of VaD will vary significantly. The traditional HIS has higher interrater reliability than the newer criteria for VaD. Prospective longitudinal studies with clinical-pathological correlation are needed to compare validity.