Persistent lymphopaenia in critically ill patients with and without sepsis: An Australian and New Zealand point prevalence study

The aim of this study was to determine the prevalence of persistent lymphopaenia, defined as an absolute lymphocyte count (ALC) < 1.0 × 109/L on both the first and second intensive care unit (ICU) days in patients with sepsis and the association of persistent lymphopaenia with advanced organ support. A prospective, multicentre, binational point prevalence study of adult patients treated in participating ICUs in June 2023 was conducted. Main outcome measures included prevalence of persistent lymphopaenia in patients with sepsis versus those without sepsis, hospital and ICU mortality, length of stay, and organ support patterns. Among 829 adult patients in 59 ICUs, 307 (37%) had persistent lymphopaenia, and 338 (40.8%) met sepsis criteria. Persistent lymphopaenia was associated with greater illness severity (mean Acute Physiology and Chronic Health Evaluation II score: 19.4 vs. 16.8, p < 0.001). Persistent lymphopaenia was more common in patients with sepsis than in those without sepsis (44.7% vs. 31.8%, p < 0.001); this difference remained after adjusting for predefined covariates (odds ratio: 1.51, 95% confidence interval: 1.12-2.03, p = 0.008). For patients with sepsis and persistent lymphopaenia, there was a 6% increase in mortality compared to those without lymphopaenia, although this did not reach statistical significance. For patients without sepsis, hospital length of stay was 16.5 days in those who had persistent lymphopaenia versus 14.4 days in those without persistent lymphopaenia (95% confidence interval: 0.5-3.7, p = 0.01). Persistent lymphopaenia is common in critically ill patients, particularly those with sepsis. Future prospective and interventional investigations are required to clarify the clinical significance of persistent lymphopaenia in critically ill adults and its potential as a therapeutic target.