Cognitive, Functional, and Mortality Outcomes of Attenuated Delirium Syndrome in Stroke Survivors

Objectives: There is a knowledge gap on the prognostic significance of subsyndromes of delirium. We describe the association of poststroke attenuated delirium syndrome (ADS) with cognitive, functional, and mortality outcomes at 3 months. Methods: A longitudinal observational study in which repeated assessments for delirium symptoms were conducted in the first week of stroke using the confusion assessment method. Attenuated delirium syndrome was characterized in survivors who were free of the full delirium syndrome but had >= 2 core features of delirium. Baseline and follow-up assessments were conducted using the Mini-Mental State Examination (MMSE), 10-word list learning and delayed recall test, Animal naming test, and Barthel index. Results: Among 150 participants recruited consecutively over 2 years, ADS was present in 32 (21.3%). Of 121 who were free of the full delirium syndrome, 21 (17.4%) had died by 3 months. Those who survived were more likely to be receiving treatment for systemic hypertension (88.5%,P= .007). In analyses adjusting for the effect of age, economic status, and systemic hypertension, ADS in the first week of stroke predicted cognitive decline at 3 months ([mean difference (MD) in MMSE scores = -3.8, 95% CI = -7.0 to -0.7,P= .019]). However, ADS was not associated with greater decline in activities of daily life (MD = -0.4, 95% CI = -2.8 to 2.0) or significant odds ratio (OR) of mortality (OR = 2.3, 95% CI = 0.8-6.3). Conclusion: Attenuated delirium syndrome may be an important marker of cognitive impairment at 3 months poststroke. Its detection may lead to identification of stroke survivors who are likely to benefit from evidence-based preventive interventions for poststroke cognitive decline.