Acute hospitalisation can be an opportunity to diagnose dementia if it can be guaranteed that confounding factors are taken into account.

To study the validity of systematic criteria for the detection of cognitive impairment and of a standardised diagnostic protocol of dementia in elderly patients hospitalised in a geriatric service.

Patients were included if they met any of the following criteria: a) previous score on the Red Cross Mental Scale (RCMS)≥2, b) Pfeiffer Questionnaire score≥5 errors and/or c) presence of delirium (Confusion Assessment Method criteria). A geriatrician conducted a cognitive history and physical examination and the following diagnostic protocol was applied: DSM-IV criteria for dementia, Mini Mental State Examination, Clock Drawing Test, Informant Questionnaire, Clinical Dementia Rating Scale, Pfeffer Scale of Instrumental Activities and Laboratory and neuroimaging tests. Each diagnosis was confirmed by another independent geriatrician.

Seven hundred and fifty-five patients were hospitalised, of which 156 (21%) met the inclusion criteria. The study could be completed during hospitalization in 114 patients (73%). The definitive diagnosis was Alzheimer's disease or mixed dementia in 63 cases (40%), vascular dementia in 17 (11%), mild cognitive impairment in 6 (4%) and delirium without previous decline in 28 (18%). Treatment recommendations were given in all cases.

Application of systematic detection criteria and a standardised diagnostic protocol made it possible to discover unknown cognitive problems in one of every five hospitalised elders and to diagnose 73% of them. Most of the diagnosis were for established dementia.