Delirium: Still Searching for Risk Factors and Effective Preventive Measures

Abstract

BACKGROUND: Noting the outcomes of delirium reveals the importance of recognizing patients who are at the highest risk for delirium and developing prevention‐oriented systems of care. Outcomes found in prospective studies are falls,1 pressure ulcers,1 longer length of stay,1–5 long‐term cognitive deficits,2,6 and functional impairment.7–9 Many of these are used as indicators of quality geriatric care. The actual incidence rates of delirium depend on the characteristics of the cohort studied and whether it included all consecutive geriatric patients,1,10 emergency surgical patients,11–13 and elective surgery patients14–16 or specifically excluded patients with terminal illness2,7,17,18 or advanced dementia.4,16 Even for a given institution to determine its incidence rate is difficult. The frequency of use of the International Classification of Diseases, Ninth Revision, code for delirium at discharge is not an accurate measure because hospitals and physicians are not likely to use a code that does not add to hospital reimbursement under Medicare. Notably, there has never been a study of the cost of either the intensity of nursing care or additional diagnostic testing involved in the care of the delirious patient. Successful prevention depends on our ability to accurately identify those specific patients at risk for delirium and measure the relative contribution of the individual risk factors. This literature review addresses two systematic reviews by Cole et al., one on risk factors for delirium and the other on the effectiveness of preventive strategies. QUESTION: What are the risk factors for incident delirium in hospitalized geriatric patients? DATA SOURCES: A Medline search was performed using the terms “delirium,”“risk factors,” and “aged” for studies published in either French or English from 1966 through 1995. Current Contents and the bibliographies were also searched for relevant articles. STUDY SELECTION CRITERIA: One hundred one studies were identified in the search, of which 27 met the following inclusion criteria: prospective enrollment of patients age 50 and older, use of an accepted diagnostic criteria for delirium, and identification of at least one risk factor. No unpublished studies were included. DATA EXTRACTION: Each article was scored with an instrument specifically developed to assess validity of a study of risk factors. The criteria used were (1) adequate description of patient characteristics and recruitment process, (2) description of selection process of cases and controls, (3) adequate measure of and adjustment for confounding variables, (4) use of a systematic measure of risk factors, (5) blinded assessment of risk factors, (6) use of an operational definition of delirium, (7) adequate sample size, and (8) report of a measure of association with confidence intervals (CI). The mean quality score of the 27 studies was 9.3 out of total possible score of 16. A checklist was used to extract data from the articles. When original data were available in two or more studies, the unadjusted odds ra...

A Model for Managing Delirious Older Inpatients

“…Rates of delirium for hospitalized elderly may be as low as 12% 5 and as high as 60% 10 . Although the prevalence of delirious patients in the DR was 69 of 196 (35.7%), the study was unable to report the overall prevalence for all older patients on the ACE unit.…”

“…Although there is an increasing body of literature about the incidence, risks, and prognosis of delirium, there is little information about interventions for delirium 9 . Although it is important to understand risk factors and preventive techniques, changes in the institutional system will likely have the greatest effect 10,11 . Necessary changes will include alterations in the hospital environment, low‐technology but labor‐intensive changes in nurse‐patient interactions, and flexibility within hospital systems that are able to individualize processes of care 10,11 .…”

Staff attitudes towards older patients with cognitive impairment: need for improvements in acute care

“…A reasonable interpretation of these findings is that many older patients are admitted with, or develop a cognitive dysfunction and that they may not receive care that meet their needs if this remains undetected. In addition, not having a valid and reliable baseline cognitive status for each patient through an admittance cognitive screening makes it difficult to identify patients at the highest risk for developing delirium and to commence targeted preventive strategies (Zeleznik 2001, Fick et al 2002. It is well known that patients with cognitive impairments are prone to delirium, as patients with dementia have a reported fivefold risk of developing delirium during a hospital stay (Royal College of Psychiatrists 2005).…”

The person-centred care of older people with cognitive impairment in acute care scale (POPAC)

“…It has been estimated that as much as 30–40% of incident delirium may be preventable, for example, through screening and preventive measures (Inouye 2006). Thus, high quality care of patients with cognitive impairment and delirium prevention depends to a large extent on the ability of staff to identify specific patients at risk, to evaluate cognition and to intervene against potential risk factors (Dick 1998, Zeleznik 2001, Waszynski 2007).…”

“…It has been estimated that as much as 30-40% of incident delirium may be preventable, for example, through screening and preventive measures (Inouye 2006). Thus, high quality care of patients with cognitive impairment and delirium prevention depends to a large extent on the ability of staff to identify specific patients at risk, to evaluate cognition and to intervene against potential risk factors (Dick 1998, Zeleznik 2001, Waszynski 2007). It has further been described that best practice models of acute care for older people with cognitive impairment consists of using gerontological expertise, targeted assessment techniques, discharge planning and enhanced interdisciplinary communication (Hickman et al 2007).…”