Confusional state in stroke: relation to preexisting dementia, patient characteristics, and outcome.

BACKGROUND AND PURPOSE Acute confusional state (ACS) is frequent in hospitalized stroke patients. We previously showed that 16% of patients admitted for a stroke have preexisting dementia. The extent to which preexisting cognitive decline is associated with a risk of ACS at the acute stage of stroke remains to be systematically examined. The aim of this study was to evaluate the prevalence of ACS in acute stroke patients, to study the influence of preexisting cognitive decline and other patient characteristics, and to evaluate the influence of ACS on outcome. METHODS We diagnosed ACS using DSM-IV criteria and the Delirium Rating Scale with a cutoff of 10 in 202 consecutive stroke patients aged 40 years or older (median age, 75 years; range, 42 to 101 years). Cognitive functioning before stroke was assessed with the Informant Questionnaire on Cognitive Decline in the Elderly. RESULTS Forty-nine stroke patients (24.3%; 95% CI, 18.3% to 30.2%) had an ACS during hospitalization. Using logistic regression analysis, we found preexisting cognitive decline (P=0.006) and metabolic or infectious disorders (P=0.008) to be independent predictors of ACS. Functional, but not vital, prognosis was worse in patients with ACS at discharge and 6 months after stroke. CONCLUSIONS ACS occurs in one fourth of stroke patients older than 40 years. Its occurrence requires inquiry for a preexisting cognitive decline, which usually remains unrecognized in the absence of a systematic evaluation.