Risk factors and outcomes among delirium subtypes in adult ICUs: A systematic review

Use systematic review methodology to summarize risk factors and outcomes for each delirium subtype (hypoactive, hyperactive and mixed) in an adult ICU population.

We searched the MEDLINE, Embase, CINAHL, SCOPUS, Web of Science and PsycINFO databases from database inception until August 13, 2018, with no restrictions.

Of 9635 abstracts, 20 studies were included. Older age was not associated with any delirium subtype in 4/7 (57%) studies. Sex was not associated with any delirium subtype in 4/4 (100%) studies. Mortality was consistently associated with hypoactive delirium in 4/7 (57%) studies. The evidence supporting the association of APACHE-II score, mechanical ventilation, length of stay, duration of delirium and removal of tubes were inconsistent across studies.

Although included studies reported on many subtype-specific risk factors and outcomes, heterogeneity in reporting and methodological quality limited the generalizability of the results and the evidence for many subtype-specific risk factors or outcomes is inconsistent across studies. Standardized methodology and the creation of a universal template for collecting data in ICU delirium studies are essential moving forward; helping to identify subtype-specific risk factors or outcomes and strengthen the association of potential risk factors or outcomes.