Studies confirm accuracy of new criteria for sepsis in predicting mortality risks

A new measurement used to diagnose sepsis in the ED known as the quick Sequential Organ Failure Assessment, or qSOFA, score was more accurate in predicting mortality among patients with a suspected infection than previous criteria. In the ICU, however, qSOFA did not perform as well as the full version of the assessment tool, according to two studies published today in JAMA.

Last year, members of the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) task force redefined sepsis as “a life-threatening organ dysfunction caused by a dysregulated host response to infection,” Yonathan Freund, MD, PhD, of the Pitié-Salpêtrière Hospital in Paris, France, and colleagues reported. They recommended replacing systemic inflammatory response syndrome (SIRS) criteria used to identify sepsis with the SOFA score. According to the researchers, sepsis is now identified as two-point or more increase in the SOFA score among patients with a suspected infection. The task force introduced the qSOFA score to screen for sepsis in settings where all components of SOFA are not routinely measured such as the ED. Components of the qSOFA score include a respiratory rate greater than 21 breaths per minute, a systolic arterial blood pressure of 100 mm Hg or less, and altered mental status.

qSOFA useful in ED

For an international prospective cohort study, Freund and colleagues assessed the efficacy of qSOFA in 879 patients with suspected infections who were treated at one of 30 participating EDs in France, Spain, Belgium or Switzerland between May and June 2016. Components of the qSOFA score were collected in the ED when patients’ highest respiratory rate, lowest systolic blood pressure and lowest Glasgow Coma Scale score were reported. The primary endpoint was in-hospital morality.

According to the data, respiratory infections were the most common type of infections, accounting for 43% of cases. A score of two or higher was recorded in 25% of patients when using qSOFA, 34% of patients when using SOFA, 74% of patients when using SIRS, and in 20% of patients when using previous criteria for severe sepsis, which included at least two or more components of SIRS and a blood lactate concentration of 2 mmol/L or greater.

The overall in-hospital mortality rate was 8%. The rate among patients with qSOFA scores less than 2 was 3% (95% CI; 2-5) vs. 24% (95% CI, 18-30) among those with a score of 2 or higher (absolute difference, 21%; 95% CI, 15-26).

The researchers found that qSOFA was more accurate in predicting in-hospital mortality than both SIRS and previous criteria for severe sepsis (area under the receiver operating curve [AUROC] = 0.8; 95% CI, 0.74-0.85 vs. 0.15; 95% CI, 0.09-0.22); P < .001). The hazard ratio of a qSOFA score of two or higher for in-hospital mortality was 6.2 (95% CI, 3.8-10.3) vs. 3.5 (95% CI, 2.2-5.5) for previous severe sepsis criteria. Freund and colleagues applied lactate measurements to the qSOFA score to determine whether its use increased accuracy; however, they observed no added value.

“This along with other findings could results in a complete change of the current clinical approach because the severity of sepsis up until now has been assessed in ED patients using lactate levels,” the researchers wrote.

Further analyses using the qSOFA score to predict ICU admission and a composite of death or ICU admission of more than 72 hours yielded similar results. The researchers concluded that their findings support the use of Sepsis-3 criteria in ED settings.

“In addition to its improved performance, qSOFA may be practical for use in the ED,” they wrote. “The endorsement of the Sepsis-3 criteria would allow not only a more accurate recognition of critically ill patients but also an earlier detection because qSOFA can be assessed immediately upon arrival and does not require any supplemental investigation such as leukocytosis or blood lactate.”

SOFA more accurate than qSOFA in ICU

In a separate study conducted by Eamon P. Raith, MBBS, MACCP, of the department of intensive care and hyperbaric medicine at Alfred Hospital, Prahran, and the School of Medicine at the University of Adelaide, Australia, and colleagues, SOFA performed better than both qSOFA and SIRS criteria in predicting mortality in ICU settings. These results correspond with findings from the Sepsis-3 task force.

“This study confirmed that, as already suggested in the consensus statement, the qSOFA score had little additional predictive value over the SIRS criteria among patients admitted to the ICU with suspected infection, and that among these patients, the use of qSOFA may be low,” Raith and colleagues wrote.

The researchers conducted a retrospective cohort analysis of 184,875 admitted to one of 182 ICUs in Australia and New Zealand for an infection from 2000 to 2015. SOFA, qSOFA and SIRS scores were assessed within the first 24 hours of admission.

In this cohort, 90% of patients had a SOFA score of 2 or higher, 86.7% had a SIRS score of two or higher and 54.5% had a qSOFA score of two or higher. Pneumonia was the most common diagnosis, occurring in 17.7% of patients.

More than 18% of patients died in the hospital, and 55.7% either died or had an ICU length of stay of 3 days or more. Compared with patients who had less than 2 points, the in-hospital morality rate among those with 2 or more points was 20.2% vs. 4.4% for SOFA; 19.9% vs. 9.8% for SIRS; and 22.8% vs. 13.6% for qSOFA.

SOFA was more accurate in predicting in-hospital mortality (AUROC = 0.753; 99% CI, 0.75-0.757) than both SIRS (AUROC = 0.589; 99% CI, 0.585-0.593) and qSOFA (AUROC = 0.607; 99% CI, 0.603-0.611; P < .001). The findings were consistent in multiple sensitivity analyses and similar to those from additional analyses predicting mortality or an ICU length of stay of 3 or more days.

In a related editorial, Francois Lamontagne, MD, of the department of medicine at the Université de Sherbrooke, Canada, and the Intensive Care National Audit & Research Centre in London, and colleagues wrote that the results were not surprising, given that the task force had come to similar conclusions. However, they noted that more research is needed to determine whether qSOFA is effective in identifying patients who have or may develop sepsis outside of the ICU in lower- and middle-income settings.

“Ultimately, the utility of qSOFA will likely become surpassed if and when highly accurate, rapid diagnostic tests for sepsis emerge,” Lamontagne and colleagues wrote. “For now, however, outside the ICU in the high-income settings where it has been tested, qSOFA appears a simple, rapid, inexpensive, and valid way to identify — among patients with suspected infection — those at a higher risk of having or developing sepsis.” – by Stephanie Viguers

References:

Freund Y, et al. JAMA. 2017;doi:10.1001/jama.2016.20329.

Lamontagne F, et al. JAMA. 2017;doi:10.1001/jama.2016.19684.

Raith EP, et al. JAMA. 2017;doi:10.1001/jama.2016.20328.

Disclosures: Freund reports receiving lecturer fees from Daichi-Sankyo. Lamontagne reports being an investigator for a study funded by GlaxoSmithKline and E-Motion. Please see the studies and editorial for a full list of the authors’ relevant financial disclosures.