Factors associated with a persistent delirium in the intensive care unit: A retrospective cohort study

PURPOSE: To explore differences between ICU patients with persistent delirium (PD), non-persistent delirium (NPD) and no delirium (ND), and to determine factors associated with PD.

MATERIALS AND METHODS: Retrospective cohort study including all ICU adults admitted for ≥12 h (January 2015-February 2020), assessable for delirium and followed during their entire hospitalization. PD was defined as ≥14 days of delirium. Factors associated with PD were determined using multivariable logistic regression analysis.

RESULTS: Out of 10,295 patients, 3138 (30.5%) had delirium, and 284 (2.8%) had PD. As compared to NPD (n = 2854, 27.7%) and ND (n = 7157, 69.5%), PD patients were older, sicker, more physically restrained, longer comatose and mechanically ventilated, had a longer ICU and hospital stay, more ICU readmissions and a higher mortality rate. Factors associated with PD were age (adjusted odds ratio [aOR] 1.03; 95% confidence interval [CI] 1.02-1.04); emergency surgical (aOR 1.84; 95%CI 1.26-2.68) and medical (aOR 1.57; 95%CI 1.12-2.21) referral, mean Sequential Organ Failure Assessment (SOFA) score before delirium onset (aOR 1.18; 95%CI 1.13-1.24) and use of physical restraints (aOR 5.02; 95%CI 3.09-8.15).

CONCLUSIONS: Patients with persistent delirium differ in several characteristics and had worse short-term outcomes. Physical restraints were the most strongly associated with PD.