The change over time in sepsis epidemiology has demonstrated an increase in incidence. This has significant implications on provision of adequate hospital, intensive care and rehabilitation facilities.
The INSEP study is a prospective multicentre, epidemiological and longitudinal observational study carried out by the SepNet Critical Care Trials Group (SepNet) in 2013. It aimed to overcome the risk of variations in sepsis awareness and coding over time. In addition to prospective data on sepsis incidence, a retrospective analysis of clinical data of patients with septic shock comparing differences according to SEPSIS-1 and SEPSIS-3 definitions was performed (1).
The SEPSIS-1 definition was as per ACCP/SCCM Consensus Conference Committee where severe sepsis was defined as sepsis in combination with at least one organ dysfunction related to infection (2). Septic shock was defined as severe sepsis combined with arterial hypotension, despite adequate volume resuscitation. Patients were also categorised as having septic shock according to SEPSIS-3 definitions (need of vasopressor therapy to maintain mean arterial pressure of 65 mmHg or greater and having serum lactate levels greater than 2mmol/l persisting after fluid resuscitation) (3).
133 participating ICUs at 95 hospitals in Germany took part in the study. 11,883 cases admitted to the ICU were screened for the occurrence of severe sepsis or septic shock, of which 1503 (12.6 %) cases were diagnosed. The point prevalence and incidence of severe sepsis or septic shock in ICUs was 17.9% and 11.64 per 1000 ICU days respectively.
The SEPSIS-1 definitions identified 218 patients with severe sepsis and 1285 cases with septic shock. The SEPSIS-3 definitions identified 848 of the cases defined with septic shock by SEPSIS-1 definition.
ICU and hospital mortality related to severe sepsis or septic shock was 34.3% and 40.4% respectively. Patients with septic shock had ICU and hospital mortality rates of 37.3% and 43.3%, respectively. This increased to 44.3% and 50.9%, respectively using the new SEPSIS-3 definitions for septic shock.
The incidence of sepsis varies between studies. This may be as a result of clinician recognition or by centre or region- specific differences.
The authors found a high incidence of nosocomial infections, which have been shown by others to have a greater risk of mortality. The observed total hospital mortality of severe sepsis or septic shock (40.4 %) is comparable to other findings in European ICUs reporting mortality rates between 36.3% and 42.8% (4). However, it remains encouraging that a decline of sepsis mortality within the last decade has also been found in this other studies (5).
In SEPSIS-3, the SIRS criteria and the term “severe sepsis” have been eliminated because one in eight patients admitted to critical care units with infection and new organ failure did not meet the condition of at least two SIRS criteria. Sepsis is defined as “life-threatening organ dysfunction (SOFA score of > 2 points) due to a dysregulated host response to infection” (2). Approximately one in eight patients admitted to critical care units with infection and new organ failure did not meet the condition of at least two SIRS criteria. This may explain why only 848 patients of the 1285 septic shock patients according the SEPSIS-1 definition were identified to be in septic shock. However, the new definition of septic shock identifies more severely ill patients with a higher mortality rate.
This prospective study therefore “demonstrates the profound change from SIRS criteria to organ dysfunction in the new SEPSIS-3 definition of sepsis or septic shock may have a major impact on frequency and mortality rates”.
Article review submitted by Nish Arulkumaran on behalf of the EJRC.
(1). SepNet Critical Care Trials Group. Incidence of severe sepsis and septic shock in German intensive care units: the prospective, multicentre INSEP study. Intensive Care Med. 2016 Dec;42(12):1980-1989. Epub 2016 Sep 29.
(2). Committee ASCC (1992) Definition for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Crit Care Med 20:864–874
(3). Singer M, Deutschman CS, Seymour CW, Shankar-Hari M, Annane D, Bauer M, Bellomo R, Bernard GR, Chiche JD, Coopersmith CM, Hotchkiss RS, Levy MM, Marshall JC, Martin GS, Opal SM, Rubenfeld GD, van der Poll T, Vincent JL, Angus DC (2016) The third international consensus definitions for sepsis and septic shock (sepsis-3). JAMA 315:801–810
(4). Levy MM, Artigas A, Phillips GS, Rhodes A, Beale R, Osborn T, Vincent JL, Townsend S, Lemeshow S, Dellinger RP (2012) Outcomes of the Surviving Sepsis Campaign in intensive care units in the USA and Europe: a prospective cohort study. Lancet Infect Dis 12:919–924
(5). Kaukonen KM, Bailey M, Suzuki S, Pilcher D, Bellomo R (2014) Mortality related to severe sepsis and septic shock among critically ill patients in Australia and New Zealand, 2000–2012. JAMA 311:1308–1316