Validation of the Rowland Universal Dementia Assessment Scale (RUDAS) in a multicultural sample across five Western European countries: diagnostic accuracy and normative data

Background:: With increasing cultural diversity and growing elderly immigrant populations in Western European countries, the availability of brief cognitive screening instruments adequate for assessment of dementia in people from diverse backgrounds becomes increasingly important. The aim of the present study was to investigate diagnostic accuracy of the Rowland Universal Dementia Assessment Scale (RUDAS) in a multicultural sample and to calculate normative data as a basis for demographic adjustment of RUDAS scores. Methods:: The study was a prospective international cross-sectional multi-center study. Receiver operating characteristic curve analysis was used to examine diagnostic accuracy. Regression analysis was used to assess the impact of demographic variables. Results:: Data was collected from 341 cognitively intact participants and 80 people with dementia with a wide age- and educational range. Of the 421 included participants, 239 (57%) had immigrant background. The RUDAS had high diagnostic accuracy with an area under the curve (AUC) of 0.93. The optimal cut-off score was <25 (sensitivity 0.80, specificity 0.90). Regression analysis revealed that RUDAS scores were mainly affected by education and were unrelated to data collection site and immigrant status. Education-adjusted normative data was calculated as a basis for education adjustment of RUDAS scores. Applying education-adjusted RUDAS scores slightly but significantly improved diagnostic accuracy with an AUC of 0.95. Conclusion:: We found the RUDAS to have excellent diagnostic properties in our multicultural sample. However, we suggest that RUDAS scores should be adjusted for education to increase diagnostic accuracy and that the choice of cut-off score should be considered based on the clinical context and expected base rate of dementia.