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

Abstract

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 μg mL^-1 vs. 1.35 μg mL^-1 , P < 0.001). CfDNA level was high (>1.69 μg 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.

Keywords: bacteraemia; biomarker; sepsis.