The descriptive epidemiology of delirium symptoms in a large population-based cohort study: results from the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS)

Abstract

BackgroundIn the general population, the epidemiological relationships between delirium and adverse outcomes are not well defined. The aims of this study were to: (1) construct an algorithm for the diagnosis of delirium using the Geriatric Mental State (GMS) examination; (2) test the criterion validity of this algorithm against mortality and dementia risk; (3) report the age-specific prevalence of delirium as determined by this algorithm.MethodsParticipant and informant data in a randomly weighted subsample of the Cognitive Function and Ageing Study were taken from a standardized assessment battery. The algorithmic definition of delirium was based on the DSM-IV classification. Outcomes were: proportional hazard ratios for death; odds ratios of dementia at 2-year follow-up.ResultsData from 2197 persons (representative of 13,004) were used, median age 77 years, 64% women. Study-defined delirium was associated with a new dementia diagnosis at two years (OR 8.82, 95% CI 2.76 to 28.2) and death (HR 1.28, 95% CI 1.03 to 1.60), even after adjustment for acute illness severity. Similar associations were seen for study-defined subsyndromal delirium. Age-specific prevalence as determined by the algorithm increased with age from 1.8% in the 65-69 year age group to 10.1% in the ≥85 age group (p < 0.01 for trend). For study-defined subsyndromal delirium, age-specific period prevalence ranged from 8.2% (65-69 years) to 36.1% (≥85 years).ConclusionsThese results demonstrate the possibility of constructing an algorithmic diagnosis for study-defined delirium using data from the GMS schedule, with predictive criterion validity for mortality and dementia risk. These are the first population-based analyses able to account prospectively for both illness severity and an earlier study diagnosis of dementia.

Protocol for the Delirium and Cognitive Impact in Dementia (DECIDE) study: A nested prospective longitudinal cohort study

“…This is consistent across different settings: after hospitalisation [6]; in those with dementia [8, 12]; in post-operative patients [13, 14]; after critical care [11]; and in community populations [10, 15]. The only population-based study showed an 8 fold increased risk of cognitive decline following an episode of delirium [10].…”

The interface between delirium and dementia in elderly adults

“…41-48 The studies vary in design, including population-based approaches, retrospective analyses of outpatients such as memory clinic patients, evaluation of ICU inpatients and those undergoing elective surgery. Nonetheless, these multiple studies consistently suggest that an episode of delirium carries substantial dementia risk, as well as an altered trajectory of cognitive recovery following surgical procedures.…”

The Delirium and Population Health Informatics Cohort study protocol: ascertaining the determinants and outcomes from delirium in a whole population

“…A range of studies have demonstrated that delirium is associated with future long-term cognitive impairment. [9-15] However, these have major methodological limitations, either: Delirium outcomes have been measured without pre-morbid baseline cognitive assessments, i.e. observed cognitive impairment at follow-up is confounded by undiagnosed pre-existing cognitive impairment ( Figure 1, top panel );[13, 16] or Delirium has been retrospectively ascertained, so detailed information on the features any delirium is lacking ( Figure 1, middle panel ).…”

“…observed cognitive impairment at follow-up is confounded by undiagnosed pre-existing cognitive impairment ( Figure 1, top panel );[13, 16] or Delirium has been retrospectively ascertained, so detailed information on the features any delirium is lacking ( Figure 1, middle panel ). [9-12, 14, 15]…”

“…Delirium has been retrospectively ascertained, so detailed information on the features any delirium is lacking ( Figure 1, middle panel ). [9-12, 14, 15]…”