A wide range of predisposing and precipitating factors correlated with delirium, indicating that a variety of pathophysiological processes cause its development. This suggests that delirium treatment may require multiple approaches. These are the findings of a study published in JAMA Network Open.
Researchers in the United States conducted a systematic review of the literature within PubMed, Embase, Web of Science, and PsycINFO from database inception through December 2021. They analyzed the different predisposing and precipitating factors associated with the onset of delirium in adults across all clinical settings.
The researchers included 315 studies encompassing 101,144 patients across 40 countries from 1992 to 2021. Of the 315 studies, 310 took place in a hospital setting.
Of the 101,144 adults, 24,015 (23.7%) developed delirium. A total of 33 predisposing factors and 112 precipitating factors correlated with onset of delirium.
The most commonly reported predisposing factors for delirium were advanced age and cognitive impairment including dementia. One study reported that White race predisposed individuals toward the development of delirium; however, 2 larger studies contradicted this finding.
Other predisposing factors involved functional impairment, psychiatric disorders, central nervous system disorders, and cardiovascular disease. Predisposing cardiovascular factors consisted of heart failure, atrial fibrillation, atherosclerosis, hypertension, coronary artery disease, and peripheral arterial disease.
The researchers classified the 112 precipitating factors into 8 categories, including surgical factors, systemic illness or organ dysfunction, metabolic dysfunction, pharmacological treatments, trauma, iatrogenic and environmental factors, neurotransmitters, and biomarkers. Many studies reported that measures of organ failure or dysfunction, hypoxemia, anemia, or leukocytosis were precipitating factors for delirium.
In contrast, 17 factors decreased risk for delirium, particularly cognitive reserve — a measure of the ability of a person to tolerate changes or stressors on brain function. Other factors decreasing incidence of delirium included environmental and social factors, number of hours the patient was mobilized, increased brain oxygenation, increased albumin, increased mean arterial pressure, increased amyloid-beta 1-42 in the cerebrospinal fluid, and use of medications, such as opioids, vasopressors, sleep aids, anesthesia, antihypertensives, antianginals, and antiretrovirals.
The researchers noted that “These findings argue against a one-size-fits-all approach to understanding, identifying, and treating delirium; they encourage a reappraisal of delirium from the perspective of its multiple physiological pathways.”
“[T]his study may provide a starting point from which to categorize delirium episodes by etiology,” they stated.
Study limitations included lack of consistent terminology, heterogeneity of included studies (which also precluded meta-analysis), lack of quantitative measurements of risk factors correlated with delirium, and exclusion of research on COVID-19 and the pandemic as it associated with delirium.
Ormseth CH, LaHue SC, Oldham MA, Josephson SA, Whitaker E, Douglas VC. Predisposing and precipitating factors associated with delirium: a systematic review. JAMA Netw Open. Published online January 6, 2023. doi:10.1001/jamanetworkopen.2022.49950