Time of delirium onset and prognosis amongst Southern Brazilian hospitalized elderly patients

The prognostic significance of delirium in hospitalized elderly has not yet been fully clarified. Objectives The present study was designed to evaluate the relationship between prevalent delirium (PrD), incident delirium (InD) and final outcome. Methods A historical cohort of 261 patients was selected. delirium was diagnosed using the Confusion Assessment Method. Results The total frequency of delirium detected was 42.5%-31.4% PrD and 16.2% InD. Among patients with InD, the average length of hospital stay was 9.1 days longer than for patients without delirium (p=0.002), and the hospital mortality associated with InD was 48% versus 2.7% for those without delirium (p< 0.001). However, no difference was observed between patients with PrD and those without delirium. Conclusions These results suggest that, when investigating delirium and prognosis amongst hospitalized elderly, it is fundamental to differentiate in terms of time of onset. Furthermore, the absence of delirium seems to be an important protective factor.