Abstract
Background: delirium affects up to 40% of older hospitalised patients, but there has been no systematic review focussing on risk factors for incident delirium in older medical inpatients. We aimed to synthesise data on risk factors for incident delirium and where possible conduct meta-analysis of these.Methods: PubMed and Web of Science databases were searched (January 1987–August 2013). Studies were quality rated using the Newcastle-Ottawa Scale. We used the Mantel–Haenszel and inverse variance method to estimate the pooled odds ratio (OR) or mean difference for individual risk factors.Results: eleven articles met inclusion criteria and were included for review. Total study population 2338 (411 patients with delirium/1927 controls). The commonest factors significantly associated with delirium were dementia, older age, co-morbid illness, severity of medical illness, infection, ‘high-risk’ medication use, diminished activities of daily living, immobility, sensory impairment, urinary catheterisation, urea and electrolyte imbalance and malnutrition. In pooled analyses, dementia (OR 6.62; 95% CI (confidence interval) 4.30, 10.19), illness severity (APACHE II) (MD (mean difference) 3.91; 95% CI 2.22, 5.59), visual impairment (OR 1.89; 95% CI 1.03, 3.47), urinary catheterisation (OR 3.16; 95% CI 1.26, 7.92), low albumin level (MD −3.14; 95% CI −5.99, −0.29) and length of hospital stay (OR 4.85; 95% CI 2.20, 7.50) were statistically significantly associated with delirium.Conclusion: we identified risk factors consistently associated with incident delirium following admission. These factors help to highlight older acute medical inpatients at risk of developing delirium during their hospital stay.
Highlights
Delirium is a complex neuropsychiatric syndrome characterised by acute onset of disturbance of consciousness and fluctuating changes in cognition, attention and perceptual disturbance [1]
Dementia (OR 6.62; 95% CI 4.30, 10.19), illness severity (APACHE II) (MD 3.91; 95% CI 2.22, 5.59), visual impairment, urinary catheterisation, low albumin level (MD −3.14; 95% CI −5.99, −0.29) and length of hospital stay were statistically significantly associated with delirium
Conclusion: we identified risk factors consistently associated with incident delirium following admission
Summary
Delirium is a complex neuropsychiatric syndrome characterised by acute onset of disturbance of consciousness and fluctuating changes in cognition, attention and perceptual disturbance [1] It is the most common reason for acute cognitive dysfunction in hospitalised older people. The UK National Institute for Health and Care Excellence (NICE) suggests screening for possible delirium based on four risk factors: age 65 or over, dementia, presentation with hip fracture and severity of illness [4]. These recommendations were developed from studies of a wide range of clinical populations recruited from surgical, intensive care and general medical settings. Other predictive models for delirium in older people with general medical admission include a wider range of factors such as malnutrition, use of a urinary catheter and physical restraints [5]
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