Phenomenological Subtypes of Delirium in Older Persons: Patterns, Prevalence, and Prognosis

Background: Delirium is an acute confusional state that is common, preventable, and life-threatening. Objective: The authors investigated the phenomenology of delirium severity as measured with the Memorial Delirium Assessment Scale among 441 older patients (age 65 and older) admitted with delirium in post-acute care. Methods: Using latent class analysis, they identified four classes of psychomotor-severity subtypes of delirium: 1) hypoactive/mild; 2) hypoactive/severe; 3) mixed, with hyperactive features/severe; and 4) normal/mild. Results: Among those with dementia (N = 166), the hypoactive/mild class was associated with a higher risk of mortality. Among those without dementia (N = 275), greater severity was associated with mortality, regardless of psychomotor features, when compared with the normal/mild class. Conclusion: The data suggest that instruments measuring delirium severity and psychomotor features provide important prognostic information and should be integrated into the assessment of delirium. (Psychosomatics 2009; 50: 248-254)