Septic shock is responsible for high morbidity and mortality rates and its incidence is increasing worldwide. Its evolution over the last few years and the leverage points for action to improve associated outcomes remain unclear. Our aim was to determine trends in the incidence and mortality of septic shock and associated risk factors in intensive care unit (ICU) patients and readmission rates after hospital discharge.

We performed a retrospective cohort study using data from the French national hospitalisation database, including adult patients with septic shock from 2014 to 2018. Primary outcomes were the incidence of septic shock and the hospital mortality rate at 30, 90 and 365 days. Secondary outcomes were all-cause hospital readmission.

Septic shock was identified in 187,587 ICU stays. The age- and sex-adjusted incidence rate of septic shock per 100 ICU admissions increased from 6.5% to 6.8% (P < .001); age- and sex-adjusted hospital mortality rates decreased from 47.3% to 44.5% (P < .001). The hospital readmission rate at 365 days was 65.0%. Older age, higher Charlson score, occurrence of organ failure and previous hospitalisation were associated with increased risk of mortality. Identification of a specific microorganism and a time between hospitalisation and ICU admission of less than one day were associated with a decreased risk of death.

Our study revealed an increase in the incidence of septic shock and a decrease in mortality rates. Pathogen identification and rapid admission to the ICU were associated with better outcomes. The rate of hospital readmission increased, raising questions about the discharge criteria for these patients.