Ability of lactate, procalcitonin, and criteria defining sepsis to predict 30-day mortality, bacteremia, and microbiologically confirmed infection in patients with infection suspicion treated in emergency departments

Objectives.

To evaluate lactate, procalcitonin, criteria defining systemic inflammatory response syndrome (SIRS), and the Quick Sepsis-Related Organ Failure Assessment (qSOFA) and compare their ability to predict 30-day mortality, infection with microbiologic confirmation, and true bacteremia in patients treated for infection in hospital emergency departments.

Methods.

Prospective multicenter observational cohort study. We enrolled a convenience sample of patients aged 18 years or older attended in 71 Spanish emergency departments from October 1, 2019, to March 31, 2020. Each model’s predictive power was analyzed with the area under the receiver operating characteristic curve (AUC), and predetermined decision points were assessed.

Results.

A total of 4439 patients with a mean (SD) age of 18 years were studied; 2648 (59.7%) were men and 459 (10.3%) died within 30 days. True bacteremia was detected in 899 (20.25%), and microbiologic confirmation was on record for 2057 (46.3%). The model that included the qSOFA score ($ 2) and lactate concentration ($ 0.738 mmol/L; 95% CI, 0.711-0.765 mmol/L) proved to be the best predictor of 30-day mortality, with an AUC of 0.890 (95% CI, 0.880-0.901). The model that included the SIRS score ($ 2) and procalcitonin concentration ($ 0.51 ng/mL) proved to be the best predictor of true bacteremia and microbiologic confirmation, with an AUC of 0.713 (95% CI, 0.698-0.728).

Conclusions.

A qSOFA score of 2 or more plus lactate concentration ($ 0.738 mmol/L) predict 30-day mortality better than the combination of a SIRS score of 2 or more and procalcitonin concentration. A SIRS score of 2 or more plus procalcitonin concentration ($ 0.51 ng/mL) predict true bacteremia and microbiologic confirmation.