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Original Investigation
Caring for the Critically Ill Patient
January 17, 2017

Prognostic Accuracy of the SOFA Score, SIRS Criteria, and qSOFA Score for In-Hospital Mortality Among Adults With Suspected Infection Admitted to the Intensive Care Unit

Author Affiliations
  • 1Department of Intensive Care and Hyperbaric Medicine, Alfred Hospital, Prahran, Melbourne, Australia
  • 2Discipline of Surgery, School of Medicine, University of Adelaide, Adelaide, Australia
  • 3Australian and New Zealand Intensive Care Research Centre, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Prahran, Melbourne, Australia
  • 4Department of Infectious Diseases, Alfred Hospital, Prahran, Melbourne, Australia
  • 5Department of Intensive Care, Royal Melbourne Hospital, Parkville, Melbourne, Australia
  • 6University of Melbourne, Parkville, Melbourne, Australia
  • 7Intensive Care Unit, Austin Hospital, Heidelberg, Melbourne, Australia
  • 8Centre for Outcome and Resource Evaluation, Australian and New Zealand Intensive Care Society, Melbourne, Australia
JAMA. 2017;317(3):290-300. doi:10.1001/jama.2016.20328
Key Points

Question  Does an increase of 2 or more points in Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score have greater prognostic accuracy in patients who are critically ill with suspected infection than 2 or more systemic inflammatory response syndrome (SIRS) criteria or quick SOFA (qSOFA) score points?

Findings  In this retrospective cohort analysis that included 184 875 adults, SOFA (area under the receiver operating characteristic curve [AUROC], 0.753) demonstrated significantly greater discrimination for in-hospital mortality than SIRS criteria (AUROC, 0.589) or qSOFA (AUROC, 0.607).

Meaning  Among patients admitted to the intensive care unit with suspected infection, defining sepsis by an increase in SOFA score provided greater prognostic accuracy for in-hospital mortality than either SIRS criteria or qSOFA.

Abstract

Importance  The Sepsis-3 Criteria emphasized the value of a change of 2 or more points in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score, introduced quick SOFA (qSOFA), and removed the systemic inflammatory response syndrome (SIRS) criteria from the sepsis definition.

Objective  Externally validate and assess the discriminatory capacities of an increase in SOFA score by 2 or more points, 2 or more SIRS criteria, or a qSOFA score of 2 or more points for outcomes among patients who are critically ill with suspected infection.

Design, Setting, and Participants  Retrospective cohort analysis of 184 875 patients with an infection-related primary admission diagnosis in 182 Australian and New Zealand intensive care units (ICUs) from 2000 through 2015.

Exposures  SOFA, qSOFA, and SIRS criteria applied to data collected within 24 hours of ICU admission.

Main Outcomes and Measures  The primary outcome was in-hospital mortality. In-hospital mortality or ICU length of stay (LOS) of 3 days or more was a composite secondary outcome. Discrimination was assessed using the area under the receiver operating characteristic curve (AUROC). Adjusted analyses were performed using a model of baseline risk determined using variables independent of the scoring systems.

Results  Among 184 875 patients (mean age, 62.9 years [SD, 17.4]; women, 82 540 [44.6%]; most common diagnosis bacterial pneumonia, 32 634 [17.7%]), a total of 34 578 patients (18.7%) died in the hospital, and 102 976 patients (55.7%) died or experienced an ICU LOS of 3 days or more. SOFA score increased by 2 or more points in 90.1%; 86.7% manifested 2 or more SIRS criteria, and 54.4% had a qSOFA score of 2 or more points. SOFA demonstrated significantly greater discrimination for in-hospital mortality (crude AUROC, 0.753 [99% CI, 0.750-0.757]) than SIRS criteria (crude AUROC, 0.589 [99% CI, 0.585-0.593]) or qSOFA (crude AUROC, 0.607 [99% CI, 0.603-0.611]). Incremental improvements were 0.164 (99% CI, 0.159-0.169) for SOFA vs SIRS criteria and 0.146 (99% CI, 0.142-0.151) for SOFA vs qSOFA (P <.001). SOFA (AUROC, 0.736 [99% CI, 0.733-0.739]) outperformed the other scores for the secondary end point (SIRS criteria: AUROC, 0.609 [99% CI, 0.606-0.612]; qSOFA: AUROC, 0.606 [99% CI, 0.602-0.609]). Incremental improvements were 0.127 (99% CI, 0.123-0.131) for SOFA vs SIRS criteria and 0.131 (99% CI, 0.127-0.134) for SOFA vs qSOFA (P <.001). Findings were consistent for both outcomes in multiple sensitivity analyses.

Conclusions and Relevance  Among adults with suspected infection admitted to an ICU, an increase in SOFA score of 2 or more had greater prognostic accuracy for in-hospital mortality than SIRS criteria or the qSOFA score. These findings suggest that SIRS criteria and qSOFA may have limited utility for predicting mortality in an ICU setting.

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