The diagnosis, prevalence and prognosis of delirium in an older hospital population

Whittamore, Katherine H. (2012) The diagnosis, prevalence and prognosis of delirium in an older hospital population. MPhil thesis, University of Nottingham.

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Delirium is a syndrome which is characterised by a change in cognition, attentional difficulties and alterations to the sleep-wake cycle. In most cases it is caused by the onset of a physical illness. Delirium is more commonly found in older people aged 65 years or older, with prevalence in hospital being as high as 42%. Delirium is associated with negative outcomes such as increased length of hospital admissions, institutionalisation and mortality.

There are tools which can identify and measure delirium and its associated symptoms. The Delirium Rating Scale-Revised-98 is claimed to be a valid tool, but its use in older patients in general hospital has not been fully investigated and there is limited research to support its validity in such a population.

A cohort study of older people with mental health problems admitted to general hospital was used to establish whether the DRS–R–98 was able to distinguish delirium from other mental health problems, to examine the association between DRS-R-98 scores, demographic variables and health problems and to study outcomes associated with delirium. 250 patients over 70 years admitted to hospital as an emergency and likely to have a mental health problem on the basis of screening were recruited and 249 completed a battery of questionnaires including the DRS-R-98 at baseline. 180 days later 121 participants completed a follow-up questionnaire. 128 participants were lost to follow-up due to refusal of the outcomes questionnaire, ill-health, withdrawal, mortality or being un-contactable after the baseline questionnaire.

Delirium was common in the study population (43%).The odds of having delirium increased with the presence of dementia (odds ratio=6.7) and functional disability (odds ratio=4.5). It was not significantly associated with mortality or length of stay in hospital. It was associated with recoverable cognitive impairment.

The DRS-R-98 has reasonable content, concurrent and predictive validity but compared with clinician diagnosis the sensitivity and specificity of the DRS-R-98 were modest (about 0.75). The validity of the DRS-R-98 was not as strongly supported as in other research, which reported sensitivity and specificity as high as 0.98 and 0.77 respectively. This could be due to the differences in participant populations, as the participants of this study were all older patients with mental health problems on general hospital wards.

In view of its ability to discriminate groups the DRS-R-98 is sufficiently valid for use in epidemiological research, but its moderate sensitivity and specificity make it unsuitable for use alone in clinical practice on individual patients, especially in populations where co-morbid dementia is prevalent.

Item Type: Thesis (University of Nottingham only) (MPhil)
Supervisors: Gladman, J.R.F.
Harwood, R.H.
Subjects: W Medicine and related subjects (NLM Classification) > WL Nervous system
W Medicine and related subjects (NLM Classification) > WM Psychiatry
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Community Health Sciences
Item ID: 12651
Depositing User: EP, Services
Date Deposited: 05 Sep 2012 13:24
Last Modified: 15 Dec 2017 07:32

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