[Cost effectiveness of the diagnostic study of dementia in an extra-hospital Neurology service]. / Rentabilidad del estudio diagnóstico de la demencia en una consulta extrahospitalaria de Neurología.

AIM: The purpose of this study was to analyse the cost effectiveness of the complementary tests in the diagnosis of reversible causes of dementia in an extra-hospital Neurology service. PATIENTS AND METHODS: Patients referred to the Neurology service from Primary Care with a diagnosis of dementia according to DSM-III-R criteria. The following routine complementary tests were performed: 1. Analyses, including blood count, biochemical study, vitamin B12 and folic levels, thyroid hormones, and syphilis serodiagnosis; 2. Neuroimaging study, consisting in computerised axial tomography or cranial magnetic resonance. RESULTS: A total of 269 consecutive patients diagnosed as suffering from dementia were included in the study. The mean age of the patients was 74.5 years (49-94 years) and 61% were females. The most frequent cause of dementia was Alzheimer's disease (79.9%). In all, 31 patients presented potentially reversible conditions (11.5%), but if we exclude depression, the dementia was only reversible in one patient (0.4%). CONCLUSIONS: The percentage of patients with reversible causes of dementia in the field of extra-hospital neurology is low. The diagnostic study must be individualised according to the clinical suspicion.