Epidemiology and outcomes of people with dementia, delirium, and unspecified cognitive impairment in the general hospital: prospective cohort study of 10,014 admissions

Abstract

BackgroundCognitive impairment of various kinds is common in older people admitted to hospital, but previous research has usually focused on single conditions in highly-selected groups and has rarely examined associations with outcomes. This study examined prevalence and outcomes of cognitive impairment in a large unselected cohort of people aged 65+ with an emergency medical admission.MethodsBetween January 1, 2012, and June 30, 2013, admissions to a single general hospital acute medical unit aged 65+ underwent a structured specialist nurse assessment (n = 10,014). We defined ‘cognitive spectrum disorder’ (CSD) as any combination of delirium, known dementia, or Abbreviated Mental Test (AMT) score < 8/10. Routine data for length of stay (LOS), mortality, and readmission were linked to examine associations with outcomes.ResultsA CSD was present in 38.5% of all patients admitted aged over 65, and in more than half of those aged over 85. Overall, 16.7% of older people admitted had delirium alone, 7.9% delirium superimposed on known dementia, 9.4% known dementia alone, and 4.5% unspecified cognitive impairment (AMT score < 8/10, no delirium, no known dementia). Of those with known dementia, 45.8% had delirium superimposed. Outcomes were worse in those with CSD compared to those without – LOS 25.0 vs. 11.8 days, 30-day mortality 13.6% vs. 9.0%, 1-year mortality 40.0% vs. 26.0%, 1-year death or readmission 62.4% vs. 51.5% (all P < 0.01). There was relatively little difference by CSD type, although people with delirium superimposed on dementia had the longest LOS, and people with dementia the worst mortality at 1 year.ConclusionsCSD is common in older inpatients and associated with considerably worse outcomes, with little variation between different types of CSD. Healthcare systems should systematically identify and develop care pathways for older people with CSD admitted as medical emergencies, and avoid only focusing on condition-specific pathways such as those for dementia or delirium alone.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-017-0899-0) contains supplementary material, which is available to authorized users.

Hospital outcomes of older people with cognitive impairment: An integrative review

“…In most studies, CI or dementia increased length of hospital stay (LOS) . (Table ) Patients with DSD had longer mean LOS than those with dementia or delirium alone . Concurrent dementia extends stays in older patients with hip fracture and haemorrhagic peptic ulcer disease .…”

“…Moderate and severe CI was associated with mortality after ICU admission, even adjusting for acuity scores (Acute Physiology and Chronic Health Evaluation II . A large cohort demonstrated significant differences in mortality for patients with CI but no diagnosis of dementia as compared to patients with no CI (11.8% vs 9.0%), and a further study showed a difference between “all‐cause” CI and no CI (13.6% vs 9.0%) . The presence of CI, regardless of dementia, may independently predict in‐hospital mortality, with the highest risk in patients with severe CI …”

“…In most studies, CI or dementia increased length of hospital stay (LOS) . (Table ) Patients with DSD had longer mean LOS than those with dementia or delirium alone .…”

Length of hospital stay and dementia: A systematic review of observational studies

“…Furthermore, 1 study reported a 72% lower odds for PWD to have a LOS of 10 days or more compared to PwoD (95% CI: 0.1‐0.4) . With exception of 1 study conducted in Ireland, the remaining studies across Europe reported a longer LOS for PWD of up to 22 days . Within countries, the different studies were consistent in reporting a longer LOS for PWD compared to PwoD; however, the difference in the LOS varied up to 13 days …”

“…Seventeen studies across 7 countries were conducted in Europe: 3 studies each in Italy, Germany, Ireland, and the UK, 2 studies from Austria and Finland, as well as 1 study from Spain . The difference in LOS among PWD compared to PwoD ranged from 0.4 to 22 days .…”