Incidence, organ dysfunction and mortality in severe sepsis: a Spanish multicentre study

Abstract

Introduction: Sepsis is a leading cause of admission to non-cardiological intensive care units (ICUs) and the second leading cause of death among ICU patients. We present the first extensive dataset on the epidemiology of severe sepsis treated in ICUs in Spain.

Methods: We conducted a prospective, observational, multicentre cohort study, carried out over two 3-month periods in 2002. Our aims were to determine the incidence of severe sepsis among adults in ICUs in a specific area in Spain, to determine the early (48 h) ICU and hospital mortality rates, as well as factors associated with the risk of death.

Results: A total of 4,317 patients were admitted and 2,619 patients were eligible for the study; 311 (11.9%) of these presented at least 1 episode of severe sepsis, and 324 (12.4%) episodes of severe sepsis were recorded. The estimated accumulated incidence for the population was 25 cases of severe sepsis attended in ICUs per 100,000 inhabitants per year. The mean logistic organ dysfunction system (LODS) upon admission was 6.3; the mean sepsis-related organ failure assessment (SOFA) score on the first day was 9.6. Two or more organ failures were present at diagnosis in 78.1% of the patients. A microbiological diagnosis of the infection was reached in 209 episodes of sepsis (64.5%) and the most common clinical diagnosis was pneumonia (42.8%). A total of 169 patients (54.3%) died in hospital, 150 (48.2%) of these in the ICU. The mortality in the first 48 h was 14.8%. Factors associated with early death were haematological failure and liver failure at diagnosis, acquisition of the infection prior to ICU admission, and total LODS score on admission. Factors associated with death in the hospital were age, chronic alcohol abuse, increased McCabe score, higher LODS on admission, DeltaSOFA 3-1 (defined as the difference in the total SOFA scores on day 3 and on day 1), and the difference of the area under the curve of the SOFA score throughout the first 15 days.

Conclusions: We found a high incidence of severe sepsis attended in the ICU and high ICU and hospital mortality rates. The high prevalence of multiple organ failure at diagnosis and the high mortality in the first 48 h suggests delays in diagnosis, in initial resuscitation, and/or in initiating appropriate antibiotic treatment.

Figure 1

Episodes of severe sepsis recorded in the patients admitted to the ICUs.

Figure 2

Cumulative hospital mortality. Numbers in squares: cumulative mortality in different days.

Figure 3

Time course of mortality in non-survivors. Cumulative percentage of non-survivors (n = 169) after diagnosis of severe sepsis.

Figure 4

Mortality by the number of organ failures at the time of diagnosis of severe sepsis (day 0 (D0)). Organ failures defined according to Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study criteria [16]. ICU, intensive care unit.

Figure 5

Evolution of the SOFA score over time. Upper panel: entire group of patients. Lower panel: area under the curve (AUC) of the Sepsis-related Organ Failure Assessment (SOFA) score trends in survivors and non-survivors. CI, confidence interval of the difference of the standardised AUC between survivors and non-survivors; SD, standard deviation.