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Outcome of delirium in critically ill patients: systematic review and meta-analysis

BMJ 2015; 350 doi: (Published 03 June 2015) Cite this as: BMJ 2015;350:h2538

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  1. Jorge I F Salluh, professor1,
  2. Han Wang, specialist researcher2,
  3. Eric B Schneider, assistant professor2,
  4. Neeraja Nagaraja, postdoctoral research fellow2,
  5. Gayane Yenokyan, assistant scientist3,
  6. Abdulla Damluji, postdoctoral fellow4,
  7. Rodrigo B Serafim, assistant professor15,
  8. Robert D Stevens, associate professor6
  1. 1D’OR Institute for Research and Education, Rio de Janeiro, Brazil
  2. 2Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
  3. 3Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
  4. 4Elaine and Sydney Sussman Cardiac Catheterization Laboratories, Cardiovascular Division, University of Miami Miller School of Medicine, Miami, FL, USA
  5. 5Department of Internal Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
  6. 6Department of Anesthesiology and Critical Care Medicine, Neurology, Neurosurgery, and Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
  1. Correspondence to: R D Stevens
  • Accepted 7 April 2015


Objectives To determine the relation between delirium in critically ill patients and their outcomes in the short term (in the intensive care unit and in hospital) and after discharge from hospital.

Design Systematic review and meta-analysis of published studies.

Data sources PubMed, Embase, CINAHL, Cochrane Library, and PsychINFO, with no language restrictions, up to 1 January 2015.

Eligibility criteria for selection studies Reports were eligible for inclusion if they were prospective observational cohorts or clinical trials of adults in intensive care units who were assessed with a validated delirium screening or rating system, and if the association was measured between delirium and at least one of four clinical endpoints (death during admission, length of stay, duration of mechanical ventilation, and any outcome after hospital discharge). Studies were excluded if they primarily enrolled patients with a neurological disorder or patients admitted to intensive care after cardiac surgery or organ/tissue transplantation, or centered on sedation management or alcohol or substance withdrawal. Data were extracted on characteristics of studies, populations sampled, identification of delirium, and outcomes. Random effects models and meta-regression analyses were used to pool data from individual studies.

Results Delirium was identified in 5280 of 16 595 (31.8%) critically ill patients reported in 42 studies. When compared with control patients without delirium, patients with delirium had significantly higher mortality during admission (risk ratio 2.19, 94% confidence interval 1.78 to 2.70; P<0.001) as well as longer durations of mechanical ventilation and lengths of stay in the intensive care unit and in hospital (standard mean differences 1.79 (95% confidence interval 0.31 to 3.27; P<0.001), 1.38 (0.99 to 1.77; P<0.001), and 0.97 (0.61 to 1.33; P<0.001), respectively). Available studies indicated an association between delirium and cognitive impairment after discharge.

Conclusions Nearly a third of patients admitted to an intensive care unit develop delirium, and these patients are at increased risk of dying during admission, longer stays in hospital, and cognitive impairment after discharge.


  • Contributors: JS and RDS designed the study, analyzed and interpreted data, and wrote the manuscript. ES, NN, and GY did the statistical analysis and interpreted the data. AD collected data. RS collected, analyzed, and interpreted data, and wrote the manuscript. RDS is guarantor.

  • Funding: The study was performed with institutional funding.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organization for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not required.

  • Transparency: The lead author (the manuscript’s guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

  • Data sharing: No additional data available.

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