Impact of Delirium Onset and Duration on Mortality in Patients With Cancer Admitted to the ICU.

BACKGROUND: Little is known on the effects of delirium onset and duration on outcome in critically ill patients with cancer.

OBJECTIVES: To determine the impact of delirium onset and duration on intensive care unit (ICU) and hospital mortality and length of stay (LOS) in patients with cancer.

METHODS: Of the 915 ICU patients admitted in 2018, 371 were included for analysis after excluding for terminal disease, <24-h ICU stay, lack of active cancer and delirium. Delirium was defined as early if onset was within 2 days of ICU admission, late if onset was on day 3 or later, short if duration was 2 days or less, and long if duration was 3 days or longer. Patients were placed into 4 combination groups: early-short, early-long, late-short, and late-long delirium. Multivariate analysis controlling for sex, age, metastatic disease, and predelirium hospital LOS was performed to determine ICU and hospital mortality and LOS. Exploratory analysis of long-term survival was also performed. Restricted cubic splines were performed to confirm the use of 2 days to distinguish between early versus late onset and short versus long duration.

RESULTS: A total of 32.9% (n = 122) patients had early-short, 39.1% (n = 145) early-long, 16.2% (n = 60) late-short, and 11.9% (n = 44) late-long delirium. Late-long delirium was independently associated with increased ICU (OR 4.45, CI 1.92-10.30; P  < .001) and hospital (OR 2.91, CI 1.37-6.19; P  = .005) mortality and longer ICU (OR 1.97, CI 1.58-2.47; P  < .001) LOS compared to early-short delirium. Early delirium had better overall survival at 18 months than late delirium. Long-term survival further improved when delirium duration was 2 days or less. Prediction heatmaps confirm the use of a 2-day cutoff.

CONCLUSION: Late delirium, especially with long duration, significantly worsens outcome in ICU patients with cancer and should be considered a harbinger of poor overall condition.