Phenomenological subtypes of delirium in older persons: patterns, prevalence, and prognosis

Abstract

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.

Figure 1. Response profile of four-class model with psychomotor (hypo/hyperactivity) categories

Class 1: Hypo-Severe (N=48); Class 2:Hypo-Mild (N=85); Class 3: Hyper-Severe (n=86); Class 4:Normal-Mild (n=222) This plot illustrates the mean severity rating (0-3) for 10 MDAS delirium symptoms (representing one symptom, [9] psychomotor activity, as two items, one indicating hypoactivity, another hyperactivity) with a separate line for each of four classes estimated from a latent class model. Percents in legend indicate the prevalence of class membership in the sample. Class 1 is named the hypoactive-severe class, class 2 is named the hypoactive-mild class, class 3 is named the mixed with hyperactive features-severe class, and class 4 is named the normal-mild class.