Plasma cell-free DNA and qSOFA score predict 7-day mortality in 481 emergency department bacteraemia patients.

Background. A few studies have shown that both quick Sequential Organ Failure Assessment (qSOFA) score and cell-free DNA (cfDNA) have potential use as a prognostic marker in patients with infection. We studied these two markers alone and in combination to identify those emergency department (ED) patients with the highest risk of death. Methods. Plasma cfDNA level was studied on days 0 to 4 after admittance to the ED from 481 culture-positive bloodstream infection cases. The qSOFA score was evaluated retrospectively according to Sepsis-3 definitions. The primary outcome was death by day 7. Results. CfDNA on day 0 was significantly higher in nonsurvivors than in survivors (2.02 mu g mL(-1) vs. 1.35 mu g mL(-1), P<0.001). CfDNA level was high (>1.69 mu g mL(-1)) in 134 (28%) of 481 cases, and the qSOFA score was 2 in 128 (28%) of 458 cases. High cfDNA and qSOFA score >= 2 had 70% and 77% sensitivity and 76% and 76% specificity in predicting death by day 7, respectively. High cfDNA alone had odds ratio (OR) of 7.7 (95% CI 3.9-15.3) and qSOFA score >= 2 OR of 11.6 (5.5-24.3), but their combination had OR of 20.3 (10.0-41.4) in predicting death by day 7 when compared with those with low cfDNA and qSOFA score <2. Amongst the five cases with the highest cfDNA levels, there were three patients with severe disseminated intravascular coagulation. Conclusion. CfDNA and qSOFA score can be used independently to identify those bacteraemia patients at high risk of death, and combining these two markers gives additional advantage.