Cell-free DNA increase over first 48 hours in emergency intensive care unit predicts fatal outcome in patients with shock

Objective To investigate whether circulating cell-free (cf)-DNA levels are a useful biomarker for survival in patients with shock in the emergency intensive care unit (EICU). Methods This prospective observational study enrolled patients admitted to the EICU diagnosed with shock. Blood cf-DNA levels were analysed on admission, and after 24 and 48h. As a measure of circulating cf-DNA, copy number of the -globin gene in plasma was assessed using quantitative real-time polymerase chain reaction. Results Circulating cf-DNA levels were higher at hospital admission and after 24h in EICU patients with shock who died than in those who recovered. Change in cf-DNA levels over the first 48h in critical care was independently associated with 28-day mortality. The critical cut-off value for cf-DNA change over 48h in predicting 28-day mortality was +16.12% (sensitivity 68.9%, specificity 89.7%). Conclusions Increased circulating cf-DNA levels in EICU patients with shock are associated with risk of death and measuring cf-DNA change over 48h improves risk prediction. The present study suggests that cf-DNA may serve as a viable plasma biomarker of mortality risk in EICU patients with shock.