Arousal changes and delirium in acute medically-ill male older patients with and without dementia: a prospective study during hospitalization

Objectives: Previous research has characterized the prevalence, natural course and outcomes of delirium superimposed in dementia but much less is known about the relation between preexisting dementia and the emergence of altered arousal (such as drowsiness, obtundation, stupor or agitation) during acute medical illness. This study aimed to determine the natural course of delirium and abnormal arousal states in acute medically-ill older patients with and without prior dementia during hospital stay. Methods: Observational prospective study in an acute male geriatric ward. Patients aged >= 65 years old were assessed by a psychiatrist within the first 72h of admission and in every other day until discharge to determine the level of arousal and the presence of delirium. Prior cognitive impairment, sociodemographic data, chronic comorbidities, psychotropic prescription and functional status were assessed at baseline. Results: 43.5% of participants in the final sample (n= 269) had dementia. Prior dementia was associated with higher rates of moderate/severe hypoarousal (29.9% vs. 4.6%; p<0.001) and delirium (20.5% vs. 7.2%; p<0.001) at admission. RASS <= -3 at admission predicted a 4-fold increased intra-hospital mortality risk and RASS not equal 0 had a sensitivity of 82.8% and a specificity of85.9% for delirium. Conclusions: Moderate/severe hypoarousal is associated with adverse outcomes and should be assessed as part of delirium spectrum, particularly in subjects with prior dementia.