Delirium and subsyndromal delirium in the intensive care unit: In-hospital outcomes and prognosis at discharge.

BACKGROUND AND OBJECTIVE: The characteristics and outcomes of patients with subsyndromal delirium (SSD) at hospitalization are still under discussion. The objectives were to describe the incidence of delirium and SSD in the intensive care unit (ICU), to analyze the association with risk factors and to explore outcomes of delirium and SSD at hospitalization and three months after discharge.

PATIENTS AND METHODS: A prospective study, with telephone follow-up three months after discharge. The study included 270 patients over one year. Delirium and SSD were assessed with the CAM-ICU.

RESULTS: 22.96% developed delirium and 17.03% SSD. The main risk factors associated with the development of delirium were cognitive impairment (P=.000), age ≥75years (P=.019), neurological admission (P=.003), shock (P=.043), bedsores (P=.010), polypharmacy (P=.017), ARM (P=.001) and fast (P=.028), and with the development of SSD were low schooling (P=.014), Charlson >5 (P=.028), AIVD <8 (P=.001), enteral feeding (P=.000) and non-cardiovascular admission (P=.019). Overall mortality was 6% in the group without delirium (reference), 8% in SSD (P=.516) and 30% in delirium (P=.000). Median ICU length of stay was 2 (IQR, 1-2) days in the group without delirium, 3 (IQR, 2-4) days in SSD (P=.0001), and 3 (IQR, 2-7) days in delirium group (P=.0001). Three months after discharge, instrumental ADL were preserved in 50% of the group without delirium, 30% of SSD (P=.026) and 26% of delirium (P=.005).

CONCLUSIONS: The SSD group presented an intermediate prognosis between no delirium and delirium groups. It is advisable to promote its diagnosis for better risk classification.