Under-detection of delirium and impact of neurocognitive deficits on in-hospital mortality among acute geriatric and medical wards

  • G. Bellelli
    Corresponding author at: Department of Health Sciences, University of Milano-Bicocca, via Cadore 48, 20900 Monza, MB, Italy. Tel.: +39 039 233 3475; fax: +39 039 233 2220.
    Department of Health Sciences, University of Milano Bicocca, Italy

    Acute Geriatric Unit, San Gerardo Hospital, Monza, Italy

    Milan Center for Neuroscience (Neuro-Mi), Milan, Italy
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  • A. Nobili
    Department of Neuroscience, IRCCS Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
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  • G. Annoni
    Department of Health Sciences, University of Milano Bicocca, Italy

    Acute Geriatric Unit, San Gerardo Hospital, Monza, Italy

    Milan Center for Neuroscience (Neuro-Mi), Milan, Italy
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  • A. Morandi
    Department of Rehabilitation and Aged Care, Hospital Ancelle, Cremona, Italy

    Geriatric Research Group, Brescia, Italy
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  • C.D. Djade
    Department of Neuroscience, IRCCS Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
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  • D.J. Meagher
    Graduate Entry Medical School, University of Limerick, Ireland

    Cognitive Impairment Research Group, Centre for Interventions in Infection, Inflammation & Immunity (4i), Graduate Entry Medical School, University of Limerick, Ireland

    Department of Psychiatry, University Hospital Limerick, Ireland
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  • A.M.J. Maclullich
    Edinburgh Delirium Research Group, Geriatric Medicine, Division of Health Sciences, School of Clinical Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom

    Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Scotland, United Kingdom
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  • D. Davis
    MRC Unit for Lifelong Health and Ageing, University College London, United Kingdom
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  • A. Mazzone
    Department of Health Sciences, University of Milano Bicocca, Italy
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  • M. Tettamanti
    Department of Neuroscience, IRCCS Istituto di Ricerche Farmacologiche “Mario Negri”, Milano, Italy
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  • P.M. Mannucci
    Scientific Direction, IRCCS Ca' Granda Maggiore Policlinico Hospital Foundation, Milano, Italy
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  • REPOSI (REgistro POliterapie SIMI) Investigators
Published:August 31, 2015DOI:


      • Delirium is a neuropsychiatric disorder, triggered by acute medical causes.
      • Only 72 of 2551 patients recruited in our study were diagnosed with ICD-9 delirium.
      • Neurocognitive deficits which may reflect delirium were instead frequently reported.
      • Neurocognitive deficits were strongly associated with in-hospital mortality.
      • Education to improve physician's knowledge of delirium is required.



      Delirium is a neuropsychiatric disorder, triggered by medical precipitants causes. Study aims were to describe the prevalence and impact on in-hospital mortality of delirium identified through ICD-9 codes as well as evidence of neurocognitive deficits demonstrated in a population of older patients admitted to acute medical wards.


      This was a prospective cohort multicenter study of 2521 older patients enrolled in the “Registro Politerapie SIMI (REPOSI)” during the years 2010 and 2012. The diagnosis of delirium was obtained by ICD-9 codes. Cognitive function was evaluated with the Short Blessed Test (SBT) and single SBT items were used as measures of deficits in attention, orientation and memory. Combination of deficits in SBT items was used as a proxy for delirium. Logistic regression was used to evaluate the association with in-hospital mortality of delirium and combined deficits in SBT items.


      Delirium was coded in 2.9%, while deficits in attention, orientation, and memory were found in 35.4%, 29.7% and 77.5% of patients. Inattention and either disorientation or memory deficits were found in 14.1%, while combination of the 3 deficits in 19.8%. Delirium, as per ICD-9 codes, was not a predictor of in-hospital mortality. In contrast, objective deficits of inattention, in combination with orientation and memory disorders, were stronger predictors after adjusting for covariates.


      The documentation of delirium is poor in medical wards of Italian acute hospitals. Neurocognitive deficits on objective testing (in a pattern suggestive of undiagnosed delirium) should be used to raise awareness of delirium, given their association with in-hospital mortality.


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