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Delirium associated with greater in-hospital mortality risk

Delirium was identified in nearly one-third of ICU patients and was associated with a greater risk for in-hospital mortality and longer admission, according to a recent study.

“The concern about ICU delirium is relatively recent; the first landmark ICU studies about it were published in 2001 and since then it is proving to be a very important and challenging matter in health care,” Jorge Salluh, MD, PhD, from D’OR Institute for Research and Education (IDOR) in Brazil, said in a press release. “Delirium can happen due to multiple causes, even if the patient’s disease isn’t neurological.”

Salluh and colleagues from IDOR and the Johns Hopkins University School of Medicine performed a systematic review and meta-analysis to assess the clinical outcomes of delirium. Data were collected on 16,595 patients from 42 cohorts enrolled in prospective observational studies and clinical trials. Researchers pulled studies from various databases that measured at least one endpoint, including death (n = 28), ICU duration (n = 28), hospital stay (n = 22), duration of mechanical ventilation use (n = 10) and outcomes after discharge (n = 8). Studies that limited enrollment to patients with neurological disorders, patients experiencing alcohol/substance withdrawal and patients admitted to ICU after undergoing a transplant or cardiac surgery, were excluded.

Delirium was detected in 31.8% of the patients and was associated with a twofold increase in hospital mortality compared with patients without delirium (RR = 2.19; 95% CI, 1.78-2.7). Further analysis showed that illness severity was higher in patients with delirium (P = .017), and hospital mortality outcomes adjusted for illness severity, among other factors, yielded similar results (effect size = 2.72; 95% CI, 1.75-3.69).

In addition, patients with delirium required an additional 1.38 days of ICU admission and 1.79 days of mechanical ventilation compared with patients without delirium (P < .001).

Few studies evaluated cognitive impairment and mortality after hospital discharge. Two studies showed that mortality increased in patients with delirium by 6 months and another showed the duration of delirium in ICU significantly correlated with time to death 1 year after admission (HR = 1.10; 95% CI, 1.02-1.18). Other studies reported that delirium was an independent predictor of poor neuropsychological scores during follow-up at 3 and 12 months and was associated with worse cognition and executive function at 3 and 12 months.

“Research is needed to unravel the biological mechanisms governing these relations and to discover strategies and treatments that will reduce the burden of acute and long term brain dysfunction in critically ill populations,” Salluh and colleagues concluded. - by Stephanie Viguers

Disclosure: The researchers report no relevant financial disclosures.