Investigators are calling for a global review of guidelines used to diagnose sepsis, after a study showed that 1 in 8 patients with infections severe enough to necessitate admission to an intensive care unit did not meet current diagnostic criteria.
The researchers identified 109,663 patients with possible sepsis who had infection and organ failure. However, more than 13,000 patients from this group did not meet the classic criteria used to diagnose sepsis.
“To be diagnosed with sepsis, a patient must be thought to have an infection and exhibit at least 2 of the following criteria: abnormal body temperature or white blood cell count, high heart rate, high respiratory rate, or low carbon dioxide level in the blood,” said Maija Kaukonen, MD, PhD, of Monash University in Melbourne, Victoria, Australia.
“But our study found that many patients—for example, the elderly or those on medications that affect heart rate or the immune system—may not meet the classic criteria to diagnose sepsis, despite having severe infections and organ failure. If we continue to use these criteria, we may miss the opportunity to identify many critically ill patients with sepsis.”
The study was published in NEJM.
The investigators studied 1,171,797 patients from 172 intensive care units in New Zealand and Australia.
The team identified patients with infection and organ failure and categorized them according to whether they had signs meeting 2 or more systemic inflammatory response syndrome (SIRS) criteria (SIRS-positive severe sepsis) or less than 2 SIRS criteria (SIRS-negative severe sepsis).
Of the 109,663 patients who had infection and organ failure, 96,385 (87.9%) had SIRS-positive severe sepsis and 13,278 (12.1%) had SIRS-negative severe sepsis.
Over 14 years, the 2 patient groups had similar characteristics and changes in mortality. Mortality decreased from 36.1% (829/2296) to 18.3% (2037/11,119) in the SIRS-positive group (P<0.001) and from 27.7% (100/361) to 9.3% (122/1315) in the SIRS-negative group (P<0.001).
This similarity between the groups remained after the researchers adjusted their analysis for baseline characteristics. In both groups, the odds ratio was 0.96 (P=0.12).
The investigators also noted that, in the adjusted analysis, mortality increased linearly with each additional SIRS criterion (P<0.001), without any transitional increase in risk at a threshold of 2 SIRS criteria.
Rinaldo Bellomo, MD, PhD, also of Monash University, conceived this study. He said that although the classic definition of sepsis has been widely used throughout the world, he believed that, after 20 years, it was time for it to be reviewed.
“There are clear signs from this study that if we continue to use these criteria, we may fail to identify septic patients and, therefore, potentially delay their treatment,” he said.
