Earlier initiation of antibiotics was associated with lower risk of developing septic shock among ED patients with severe sepsis, a recent study found.

The retrospective cohort study included 3,929 adult patients diagnosed in an urban academic medical center with severe sepsis. All studied patients received antibiotics within 24 hours, and patients were excluded if they presented with shock. The overall mortality rate was 12.8%. Results were published online by Critical Care Medicine on Feb. 6.

Twenty-five percent of the patients progressed to sepsis shock. Patients who progressed to shock had a significantly longer median time to antimicrobial administration than those who did not (3.77 hours vs. 2.76 hours; P<0.001). Each hour until antimicrobial administration was associated with an 8% increase in progression. Time to administration was also associated with in-hospital mortality (odds ratio, 1.05; 95% CI, 1.03 to 1.07).

After multivariate logistic regression, study authors identified several factors associated with progression to shock: in addition to time to antimicrobials, also male sex, Charlson Comorbidity Index, and number of infections. Factors associated with shorter time to antimicrobial administration included age, white blood cell count, hypotension, and respiratory/lung infection.

The results indicate that not only do antibiotics inhibit progression to septic shock, “it seems that they do so in the sickest patients of the cohort, principally because they are administered earlier in these patients,” the authors said. The study emphasizes the importance of administering broad-spectrum antibiotics to severe sepsis patients as early as possible and identifies other risk factors for progression that may allow better prognostication for severe sepsis patients, the authors concluded.

The study was limited by its use of ICD-9 codes to identify patients with severe sepsis and septic shock, which likely resulted in some patients with these conditions being missed. Patients with systemic inflammatory response syndrome but no organ dysfunction would also have been excluded, but this would make the study's criteria fairly similar to the new Sepsis-3 definitions, the authors said.