THE NATURAL-HISTORY OF DELIRIUM IN OLDER HOSPITALIZED-PATIENTS - A SYNDROME OF HETEROGENEITY

Objectives: to determine the presentation, course and duration of deli rium in hospitalized older people. Design: observational cohort study. Setting: inpatient surgical and medical wards at a university hospita l. Participants: 432 people over the age of 65. Measurements: all part icipants were screened daily for confusion and, in those who were conf used, delirium was ascertained using the Diagnostic and Statistical Ma nual of Mental Disorders (DSM) III-R criteria. Those who were found to be delirious were followed daily while in hospital for evidence of de lirium, The Delirium Rating Scale (DRS) was used to describe the clini cal characteristics of delirium. Results: about 15% of subjects had de lirium. Sixty-nine percent of delirious subjects had delirium on a sin gle day The DRS total was higher on the first day of delirium for thos e with delirium on multiple days than those with delirium on a single day (P = 0.03). Among those with delirium on multiple days, there were no patterns of change over time in specific DRS items. Conclusions: d elirium in hospitalized older people is common and has a varied presen tation and time course. Clinicians and researchers need to consider th is great heterogeneity when caring for patients and when studying deli rium.