Delirium in HIV-infected patients admitted to acute medical wards post universal access to antiretrovirals in South Africa

Abstract

The prevalence of delirium in acute medical inpatients is high, with estimates ranging from 10% to 31%. [1] Short-and long-term complications of delirium include increased mortality and length of hospitalisation, post-discharge institutionalisation, and long-term functional and cognitive decline. [2] This is a considerable healthcare burden: in developed countries the cost of delirium is equal to that of falls and diabetes mellitus. [3] A number of risk factors for delirium have been identified, including predisposing factors such as dementia and advancing age and acute precipitating factors such as drugs, infections and metabolic abnormalities. [2] Protective factors include a higher level of education, a marker of cognitive reserve. [4] Unfortunately, the data on delirium outcomes and risk factors in general medical inpatients are derived almost exclusively from geriatric populations in developed countries, a very different population to acute medical admissions in developing country settings with a high HIV/tuberculosis (TB) burden. [5] Furthermore, the few studies from developing country settings such as sub-Saharan Africa (SSA) have either been conducted in medical patients aged >60 years or in specialised populations, such as psychiatric and intensive care settings. [6][7][8] In developed countries such as the USA, studies were done among HIV-infected populations before universal access to combination antiretroviral therapy (ART). [9][10][11][12][13][14] HIV targets the central nervous system (CNS) with resultant neurocognitive impairment (NCI), a well-described predisposing risk factor for delirium. Acute and opportunistic infections (OIs), also known risk factors for delirium, occur more commonly with advancing immunosuppression. It is therefore unsurprising that studies have shown high prevalence rates of delirium (3.7 -57%) in HIV-infected populations. [6,[11][12][13] Delirium in HIV is often concomitant with NCI, in 8 -22% of cases. [15] Combination ART both prevents and improves NCI and decreases the incidences of acute and OIs. Widespread access to ART may therefore mitigate delirium risk. It is unclear whether HIV infection remains an independent risk factor for delirium in acute medical admissions in endemic HIV settings with universal ART programmes. [9] Furthermore, in developing country settings such as South Africa (SA), with high This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.

Predisposing and Precipitating Factors Associated With Delirium

“…Reasons for exclusion were no diagnosis by physician or research personnel (428 studies), no characterization of predisposing or precipitating factors (338 studies), retrospective study design (86 studies), not diagnosed by reference standard (108 studies), no multivariable model (43 studies), delirium assessment not conducted in person (25 studies), not cohort or case-control design (20 studies), sample included less than 50 patients (12 studies), abstract only (18 studies), cohort previously reported (3 studies), and pediatric population (1 studies). Ultimately, 315 studies…”

“…Studies were conducted in 40 different countries, with the plurality in the United States (86 studies [27.3%]), followed by China (48 studies [15.2%]) and the Netherlands (24 studies [7.6%]). Most studies were prospective cohort studies (296 studies…”

“…A list of included studies with number of participants and NOS score is included in eTable in Supplement 1). There were 138 studies (43.8%) that excluded participants due to a language barrier (participants were excluded if they did not speak the same language that delirium assessors used).…”

“…Delirium was measured by research personnel in 171 studies (54.3%), a combination of research personnel and physicians in 5 studies (1.6%), and a physician in 139 studies …”

“…A total of 33 predisposing factors were identified. Advanced age and cognitive impairment or dementia were identified in the most studies and participants; 112 studies with 50 418 participants (among whom 9147 patients had delirium) identified age and 130 studies with 42 124 participants (among whom 9617 patients had delirium) identified cognitive impairment or dementia as factors. The following predisposing factors were variably defined across studies: functional impairment, cardiovascular disease, central nervous system disorders, and psychiatric disorders.…”