The Tuscany experimental registry for Alzheimer's disease and other dementias: how many demented people does it capture?

ABSTRACT

BACKGROUND AND AIMS: A Regional Registry for Alzheimer's Disease and Other Dementias is being tested in Tuscany (Italy) to provide a basis for epidemiological studies. Current results are presented and critically evaluated. METHODS: The Registry extracts data on cases of dementia from Hospital Discharge Records, Outpatient Service Records, Regional Mortality Registry and Disease-Specific Co-payment Exemption Records, based on ICD-9 codes of dementias, and from Prescription Records based on registered anti-dementia drug codes. A list of cases of dementia prevalent at the end of 2005 was produced by cross-checking captured cases with the Regional Mortality Registry. RESULTS: The Registry captured 47,889 cases, of which 27,796 were still alive at the end of 2005. Captured cases represent slightly less than half of all the cases of dementia estimated to be present in Tuscany among older residents (65+) according to recent prevalence studies. Conversely, of 87 subjects 65 years of age or older selected from the Registry and directly evaluated, 80 (92%) were truly cognitively impaired subjects. CONCLUSIONS: The Registry has low sensitivity, probably because not all demented individuals are diagnosed as such in current practice and/or use health services. Conversely, the Registry has high specificity, and the produced lists of prevalent dementia cases are the key to estimating health and quality-of-care indicators for the demented population, and may constitute a basis for epidemiological studies.