Clinical significance of delirium subtypes in older people

Objective: to examine the relative frequency and outcome of clinical subtypes of delirium in older hospital patients. Design: prospective observational study. Setting: acute geriatric unit in a teaching hospital. Subjects: 94 patients with delirium from a prospective study of 225 admissions. Measurements: clinical subtypes of delirium were determined according to predefined criteria. Characteristics examined in these subgroups included illness severity on admission, prior cognitive impairment, mortality, duration of hospital stay and hospital-acquired complications. Results: of the 94 patients, 20 (21%) had a hyperactive delirium, 27 (29%) had a hypoactive delirium, 40 (43%) had a mixed hypoactive-hyperactive psychomotor pattern and seven (7%) had no psychomotor disturbance. There were significant differences between the four groups in illness severity (P < 0.05), length of hospital stay (P < 0.005) and frequency of falls (P < 0.05). Patients with hypoactive delirium were sicker on admission, had the longest hospital stay and were most likely to develop pressure sores. Patients with hyperactive delirium were most likely to fall in hospital, There were no differences in aetiological factors between the groups. Conclusion: outcomes of hospitalization differ in different clinical subtypes of delirium.