Editing Delirium (section)

==Prognosis==
There is substantial evidence that delirium results in long-term poor outcomes in older persons admitted to hospital.<ref name="Witlox">{{cite journal | vauthors = Witlox J, Eurelings LS, de Jonghe JF, Kalisvaart KJ, Eikelenboom P, van Gool WA | title = Delirium in elderly patients and the risk of postdischarge mortality, institutionalization, and dementia: a meta-analysis | journal = JAMA | volume = 304 | issue = 4 | pages = 443–451 | date = July 2010 | pmid = 20664045 | doi = 10.1001/jama.2010.1013 | s2cid = 13402729 }}</ref> This systematic review only included studies that looked for an independent effect of delirium (i.e., after accounting for other associations with poor outcomes, for example co-morbidity or illness severity).

In older persons admitted to hospital, individuals experiencing delirium are twice as likely to die than those who do not (meta-analysis of 12 studies).<ref name="Witlox" /> In the only prospective study conducted in the general population, older persons reporting delirium also showed higher mortality (60% increase).<ref name="Davis">{{cite journal | vauthors = Davis DH, Muniz Terrera G, Keage H, Rahkonen T, Oinas M, Matthews FE, Cunningham C, Polvikoski T, Sulkava R, MacLullich AM, Brayne C | title = Delirium is a strong risk factor for dementia in the oldest-old: a population-based cohort study | journal = Brain | volume = 135 | issue = Pt 9 | pages = 2809–2816 | date = September 2012 | pmid = 22879644 | pmc = 3437024 | doi = 10.1093/brain/aws190 }}</ref> A large (N=82,770) two-centre study in unselected older emergency population found that delirium detected as part of normal care using the [[4AT]] tool was strongly linked to 30-day mortality, hospital length of stay, and days at home in the year following the 4AT test date.<ref>{{cite journal | vauthors = Anand A, Cheng M, Ibitoye T, Maclullich AM, Vardy ER | title = Positive scores on the 4AT delirium assessment tool at hospital admission are linked to mortality, length of stay and home time: two-centre study of 82,770 emergency admissions | journal = Age and Ageing | volume = 51 | issue = 3 | pages = afac051 | date = March 2022 | pmid = 35292792 | pmc = 8923813 | doi = 10.1093/ageing/afac051 }}</ref>

Institutionalization was also twice as likely after an admission with delirium (meta-analysis of seven studies).<ref name="Witlox" /> In a community-based population examining individuals after an episode of severe infection (though not specifically delirium), these persons acquired more functional limitations (i.e., required more assistance with their care needs) than those not experiencing infection.<ref>{{cite journal | vauthors = Iwashyna TJ, Ely EW, Smith DM, Langa KM | title = Long-term cognitive impairment and functional disability among survivors of severe sepsis | journal = JAMA | volume = 304 | issue = 16 | pages = 1787–1794 | date = October 2010 | pmid = 20978258 | pmc = 3345288 | doi = 10.1001/jama.2010.1553 }}</ref> After an episode of delirium in the general population, functional dependence increased threefold.<ref name="Davis" />

The association between delirium and dementia is complex. The systematic review estimated a 13-fold increase in dementia after delirium (meta-analysis of two studies).<ref name="Witlox" /> However, it is difficult to be certain that this is accurate because the population admitted to hospital includes persons with undiagnosed dementia (i.e., the dementia was present before the delirium, rather than caused by it). In prospective studies, people hospitalised from any cause appear to be at greater risk of dementia<ref name="Ehlenbach">{{cite journal | vauthors = Ehlenbach WJ, Hough CL, Crane PK, Haneuse SJ, Carson SS, Curtis JR, Larson EB | title = Association between acute care and critical illness hospitalization and cognitive function in older adults | journal = JAMA | volume = 303 | issue = 8 | pages = 763–770 | date = February 2010 | pmid = 20179286 | pmc = 2943865 | doi = 10.1001/jama.2010.167 }}</ref> and faster trajectories of cognitive decline,<ref name="Ehlenbach" /><ref>{{cite journal | vauthors = Wilson RS, Hebert LE, Scherr PA, Dong X, Leurgens SE, Evans DA | title = Cognitive decline after hospitalization in a community population of older persons | journal = Neurology | volume = 78 | issue = 13 | pages = 950–956 | date = March 2012 | pmid = 22442434 | pmc = 3310309 | doi = 10.1212/WNL.0b013e31824d5894 }}</ref> but these studies did not specifically look at delirium. In the only population-based prospective study of delirium, older persons had an eight-fold increase in dementia and faster cognitive decline.<ref name="Davis" /> The same association is also evident in persons already diagnosed with Alzheimer's dementia.<ref>{{cite journal | vauthors = Fong TG, Jones RN, Shi P, Marcantonio ER, Yap L, Rudolph JL, Yang FM, Kiely DK, Inouye SK | title = Delirium accelerates cognitive decline in Alzheimer disease | journal = Neurology | volume = 72 | issue = 18 | pages = 1570–1575 | date = May 2009 | pmid = 19414723 | pmc = 2677515 | doi = 10.1212/WNL.0b013e3181a4129a }}</ref>

Recent long-term studies showed that many people still meet criteria for delirium for a prolonged period after hospital discharge, with up to 21% of people showing persistent delirium at 6 months post-discharge.<ref>{{cite journal | vauthors = Cole MG, Ciampi A, Belzile E, Zhong L | title = Persistent delirium in older hospital patients: a systematic review of frequency and prognosis | journal = Age and Ageing | volume = 38 | issue = 1 | pages = 19–26 | date = January 2009 | pmid = 19017678 | doi = 10.1093/ageing/afn253 | doi-access = free }}</ref>

===Dementia in ICU survivors===
{{see also|Post-intensive care syndrome}}
Between 50% and 70% of people admitted to the ICU have permanent problems with brain dysfunction similar to those experienced by people with Alzheimer's or those with a traumatic brain injury, leaving many ICU survivors permanently disabled.<ref>{{cite journal | vauthors = Hopkins RO, Jackson JC | title = Long-term neurocognitive function after critical illness | journal = Chest | volume = 130 | issue = 3 | pages = 869–878 | date = September 2006 | pmid = 16963688 | doi = 10.1378/chest.130.3.869 | s2cid = 8118025 }}</ref> This is a distressing personal and public health problem and continues to receive increasing attention in ongoing investigations.<ref name="Harris_2018">{{Cite web | vauthors = Harris R |date=October 10, 2018 |title=When ICU Delirium Leads To Symptoms Of Dementia After Discharge |url=https://www.npr.org/sections/health-shots/2018/10/10/654445929/when-icu-delirium-leads-to-symptoms-of-dementia-after-discharge |access-date=January 24, 2024 |website=NPR}}</ref><ref name="Challenges of Delirium Management i"/>

The implications of such an "acquired dementia-like illness" can profoundly debilitate a person's livelihood level, often dismantling his/her life in practical ways like impairing one's ability to find a car in a parking lot, complete shopping lists, or perform job-related tasks done previously for years.<ref name="Harris_2018" /> The societal implications can be enormous when considering work-force issues related to the inability of wage-earners to work due to their own ICU stay or that of someone else they must care for.<ref>{{cite web |url=https://www.npr.org/sections/health-shots/2018/10/10/654445929/when-icu-delirium-leads-to-symptoms-of-dementia-after-discharge |title=When ICU Delirium Leads To Symptoms Of Dementia After Discharge | vauthors = Harris R |publisher=National Public Radio |date=October 10, 2018 |access-date=29 April 2019 |archive-date=4 May 2019 |archive-url=https://web.archive.org/web/20190504063245/https://www.npr.org/sections/health-shots/2018/10/10/654445929/when-icu-delirium-leads-to-symptoms-of-dementia-after-discharge |url-status=live }}</ref>