The systemic inflammatory response syndrome criteria and their differential association with mortality

Despite the recent Sepsis-3 consensus, the Systemic Inflammatory Response Syndrome (SIRS) criteria continue to be assessed and recommended. Such use implies equivalence and interchangeability of criteria. Thus, we aimed to test whether such criteria are indeed equivalent and interchangeable.

From 2000 to 2015, we identified patients with infection, organ failure, and at least one SIRS criterion in 179 Intensive Care Units in Australia and New. Zealand. We studied the association of different SIRS criteria with hospital mortality.

Among 131,016 patients with infection and organ failure, mortality increased from 10.6% for the respiratory rate criterion to 15.8% for the heart rate criterion (P<0.01); from 10.1% for the high leukocyte count criterion to 20.0% for a low count and from 10.1% for a high temperature to 14.4% for a low temperature criterion. With any two SIRS criteria, hospital mortality varied from 11.5% to 30.8% depending on the combination of criteria. This difference remained unchanged after adjustments and was consistent over time.

Different individual and combinations of SIRS criteria were associated with marked differences in hospital mortality. These differences remained unchanged after adjustment and over time and imply that individual SIRS criteria are not equivalent or interchangeable.