Subsyndromal Delirium in Older Long-Term Care Residents: Incidence, Risk Factors, and Outcomes

Department of Psychiatry, St. Mary's Research Centre, St. Mary's Hospital, Montreal, Canada.
Journal of the American Geriatrics Society (Impact Factor: 4.57). 10/2011; 59(10):1829-36. DOI: 10.1111/j.1532-5415.2011.03595.x
Source: PubMed


To determine the incidence of, risk factors for, and outcomes of subsyndromal delirium (SSD) in older long-term care (LTC) residents and, secondarily, to explore the use of a more-restrictive definition of SSD.
Cohort study with repeated weekly assessments for up to 6 months.
Seven LTC facilities in Montreal and Quebec City, Canada.
One hundred four LTC residents aged 65 and older and free of delirium core symptoms at baseline.
The Mini-Mental State Examination (MMSE), Confusion Assessment Method (CAM), Delirium Index (DI), Hierarchic Dementia Scale (HDS), and Barthel Index (BI) were completed at baseline. The MMSE, CAM, and DI were repeated weekly for 6 months. SSD1 required one or more CAM core symptoms; SSD2, a more-restrictive definition, required two or more CAM core symptoms. Outcomes at 6 months were decline on the MMSE, HDS, and BI; mortality; and a composite outcome.
Sixty-eight of 104 residents had SSD1. In survival analysis, the incidence was 5.2 (95% confidence interval (CI) = 4.1-6.7) per 100 person-weeks of follow-up. In multivariate analysis, risk factors were male sex and more-severe cognitive impairment at baseline. The differences in outcomes between residents with and without SSD1 were small and not statistically significant. SSD2 had a lower incidence (1.3, 95% CI = 0.9-1.9), similar risk factors, and statistically significantly worse cognitive outcomes.
SSD2 appears to be a clinically important disorder in older LTC residents. Despite limited statistical power, these findings have potentially important implications for clinical practice and research in LTC settings.

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    • "A recent cohort study has found that 68 of the 104 residents had incident subsyndromal delirium during 6 months of observation. The incidence rate was 5.2 per 100 person-weeks of follow-up (Cole et al., 2011). The risk factors for subsyndromal delirium are similar to those for classical overt delirium: advanced age, dementia, and severe illness. "
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    ABSTRACT: The present review aims to highlight this intricate syndrome, regarding diagnosis, pathophysiology, etiology, prevention, and management in elderly people. The diagnosis of delirium is based on clinical observations, cognitive assessment, physical, and neurological examination. Clinically, delirium occurs in hyperactive, hypoactive, or mixed forms, based on psychomotor behavior. As an acute confusional state, it is characterized by a rapid onset of symptoms, fluctuating course and an altered level of consciousness, global disturbance of cognition or perceptual abnormalities, and evidence of a physical cause. Although pathophysiological mechanisms of delirium remain unclear, current evidence suggests that disruption of neurotransmission, inflammation, or acute stress responses might all contribute to the development of this ailment. It usually occurs as a result of a complex interaction of multiple risk factors, such as cognitive impairment/dementia and current medical or surgical disorder. Despite all of the above, delirium is frequently under-recognized and often misdiagnosed by health professionals. In particular, this happens due to its fluctuating nature, its overlap with dementia and the scarcity of routine formal cognitive assessment in general hospitals. It is also associated with multiple adverse outcomes that have been well documented, such as increased hospital stay, function/cognitive decline, institutionalization and mortality. In this context, the early identification of delirium is essential. Timely and optimal management of people with delirium should be performed with identification of any possible underlying causes, dealing with a suitable care environment and improving education of health professionals. All these can be important factors, which contribute to a decrease in adverse outcomes associated with delirium.
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    ABSTRACT: Since the publication of DSM-III in 1980, the essential criteria for delirium have been reduced progressively through DSM-III-R to DSM-IV. As the field moves toward DSM-V and ICD-11, new data can shed light on the nosological changes that are needed so that diagnostic criteria can reflect empirical data. In this study, we reassess the existing or potential criteria for delirium. Phenomenological studies in recent years have informed the criteria for delirium, including the appropriateness of the term 'consciousness' as a core symptom of the diagnosis, additional symptoms of delirium that are frequent but are not currently part of the diagnostic criteria, subsyndromal delirium, motoric subtypes of delirium (hyperactive, hypoactive), and the association of delirium with dementia. Recent studies suggest that motoric subtypes should be included as a subtype for delirium but that subsyndromal delirium, although a useful research construct, should not be included in clinical diagnostic criteria given the frequent fluctuation in symptoms over short periods. In addition, though the core symptoms are probably adequate to make the diagnosis, clinicians must be aware of the frequency of other symptoms, for symptoms such as profound sleep disturbance or psychotic symptoms may dominate the clinical picture.
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    ABSTRACT: OBJECTIVE: To describe Confusion Assessment Method (CAM) core symptoms of delirium occurring before and after incident episodes of delirium in older long-term care (LTC) residents. A secondary objective was to describe the mean number of symptoms before and after episodes by dementia status. DESIGN: Secondary analysis of data collected for a prospective cohort study of delirium, with repeated weekly assessments for up to 6 months. SETTING: Seven LTC facilities in Montreal and Quebec City, Canada. PARTICIPANTS: Forty-one older LTC residents who had at least one CAM-defined incident episode of delirium. MEASUREMENTS: The Mini-Mental State Examination (MMSE), CAM, Delirium Index (DI), Hierarchic Dementia Scale, Barthel Index, and Cornell Scale for Depression were completed at baseline. The MMSE, CAM, and DI were repeated weekly for 6 months. The frequency, mean number, type, and duration of CAM core symptoms of delirium occurring before and after incident episodes were examined using descriptive statistics, frequency analysis, and survival analysis. RESULTS: CAM core symptoms of delirium preceded 38 (92.7%) episodes of delirium for many weeks; core symptoms followed 37 (90.2%) episodes for many weeks. Symptoms of inattention and disorganized thinking occurred most commonly. The mean number of symptoms was higher in residents with dementia but not significantly so. CONCLUSION: CAM core symptoms of delirium were frequent and protracted before and after most incident episodes of delirium in LTC residents with and without dementia. If replicated, these findings have potentially important implications for clinical practice and research in LTC settings.
    Full-text · Article · Nov 2012 · Journal of the American Geriatrics Society
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