Delirium in hospitalized patients
BACKGROUND Despite the significant burden of delirium among hospitalized adults, critical appraisal of systematic data on delirium diagnosis, pathophysiology, treatment, prevention, and outcomes is lacking. PURPOSE To provide evidence based recommendations for delirium care to practitioners, and identify gaps in delirium research. DATA SOURCES Medline, PubMed, the Cochrane Library, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) information systems fromJanuary 1966 to April 2011. STUDY SELECTION All published systematic evidence reviews (SERs) on delirium were evaluated. (c) 2012 Society of Hospital Medicine *Address for correspondence and reprint requests: Babar A. Khan, MD, MS, Indiana University Center for Aging Research, 410 West 10th St, Ste 2000, Indianapolis, IN 46202; Telephone: 317 423 5633; Fax: 317 423 5695; bakhan@iupui.edu. Additional Supporting Information may be found in the online version of this article. Disclosure: This study was supported by the National Institute on Aging (NIA) grant R01AG054205 02; and the National Institute of Mental Health (NIMH) grant R24MH080827 04. NIH Public Access Author Manuscript J Hosp Med. Author manuscript; available in PMC 2013 May 01. Published in final edited form as: J Hosp Med. 2012 September 7(7) 580 589. doi:10.1002/jhm.1949. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript DATA EXTRACTION Three reviewers independently extracted the data regarding delirium risk factors, diagnosis, prevention, treatment, and outcomes, and critically appraised each SER as good, fair, or poor using the United States Preventive Services Task Force criteria. DATA SYNTHESIS Twenty two SERs graded as good or fair provided the data. Age, cognitive impairment, depression, anticholinergic drugs, and lorazepam use were associated with an increased risk for developing delirium. The Confusion Assessment Method (CAM) is reliable for delirium diagnosis outside of the intensive care unit. Multicomponent nonpharmacological interventions are effective in reducing delirium incidence in elderly medical patients. Low dose haloperidol has similar efficacy as atypical antipsychotics for treating delirium. Delirium is associated with poor outcomes independent of age, severity of illness, or dementia. CONCLUSION Delirium is an acute, preventable medical condition with shortand long term negative effects on a patient's cognitive and functional states. Delirium is a syndrome of disturbance of consciousness, with reduced ability to focus, sustain, or shift attention, that occurs over a short period of time and fluctuates over the course of the day.1 It encompasses a variety of cognitive, behavioral, and psychological symptoms including inattention, short term memory loss, sleep disturbances, agitated behaviors, delusions, and visual hallucinations.2 Delirium complicates the care of 70% to 80% of mechanically ventilated patients in intensive care units (ICUs).3 Of 13 million patients aged 65 and older hospitalized in 2002, 10% to 52% had delirium at some point during their admission.4,5 Patients experiencing delirium have a higher probability of death during their hospital stay, adjusted for age, gender, race, and comorbidities.3,6,7 They are more vulnerable to hospitalacquired complications leading to prolonged ICU and hospital stay, new institutionalization, and higher healthcare costs.3,6,7 Even with such a range of poor outcomes, the rates of delirium recognition are low,8 resulting in inadequate management.9 There has been considerable growth in the number of articles published on delirium in recent years. Therefore, it is of value to provide a state of the art summary of robust evidence in the field to healthcare personnel and delirium investigators. We systematically reviewed the literature to identify published systematic evidence reviews (SERs) which evaluated the evidence on delirium risk factors, diagnosis, pathogenesis, prevention, treatment, and outcomes. We then summarized the data from the methodologically sound SERs to provide the reader with a clinically oriented summary of delirium literature for patient care. We also identify current gaps in delirium literature, and present future directions for delirium investigators to design studies that will enhance delirium care. DATA SOURCES AND REVIEW METHODS The domains of risk factors, diagnosis, pathophysiology, prevention, treatment, and outcomes were selected a priori to capture all relevant SERs regarding delirium based on the framework suggested by the American Delirium Society task force.10 To maximize article retrieval, a 3 step search strategy was applied. First, we searched the electronic database utilizing OVID Medline, PubMed, the Cochrane Library, and Cumulative Index of Nursing and Allied Health Literature (CINAHL) using the following delirium specific search terms: delirium, confusion, agitation, mental status change, inattention, encephalopathy, organic mental disorders, and disorientation. We combined the above terms with the following study design terms: technical report, systematic evidence review, systematic review, metaanalysis, editorial, and clinical reviews. We limited our search to human subjects. We excluded studies that: a) enrolled patients aged <18; b) enrolled patients with current or past Khan et al. Page 2 J Hosp Med. Author manuscript; available in PMC 2013 May 01. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript Diagnostic and Statistical Manual of Mental Disorders (DSM) Axis I psychotic disorders; c) did not have standardized delirium evaluation; d) evaluated alcohol or substance abuserelated delirium; e) did not use a systematic search method for identifying delirium related articles; and f) evaluated delirium sub types. We searched articles published from January 1966 through April 2011. Second, a manual search of references of the retrieved papers plus an Internet search using Google Scholar was conducted to find additional SERs. Titles and abstracts were screened by 2 reviewers (B.A.K. M.Z. Authors of the included studies were contacted as necessary. Third, a library professional at the Indiana University School of Medicine independently performed a literature search, and those results were compared with our search to retrieve any missing SERs. The methodological quality of each SER was independently assessed by 2 reviewers (B.A.K. M.Z. using the United States Preventive Services Task Force (USPSTF) Critical Appraisal for SER.11 This scale assesses parameters that are critical to the scientific credibility of an SER and categorizes the SER as poor, fair, or good (Table 1) The 2 reviewers (B.A.K. M.Z. used a data extraction form to record the following information from each SER: primary author, publication year, number and type of studies, number of participants and their mean age, study population, method for delirium diagnosis, risk factors, preventive and therapeutic interventions, and outcomes. Any disagreement between reviewers in SER selection, data extraction, or SER appraisal was resolved through discussion with a third reviewer (M.A.B. The conflicting findings among SERs were resolved by consensus and by including the findings from a good SER over a fair SER.