In ICU patients who have septic shock, the anatomic source of infection has a strong effect on the chances of survival, according to a new study from researchers in Canada.
“Understanding the local infection source in patients with septic shock may influence treatment strategies and clinical outcomes,” said researcher Peter Dodek, MD MHSc, professor of critical care medicine at the University of British Columbia in Vancouver. “Accordingly, we examined the relationship between anatomic source of infection and hospital mortality in nearly 8,000 patients who had septic shock and who were admitted to ICUs in Canada, the United States and Saudi Arabia.”
“We found that there are meaningful differences in hospital mortality among anatomic sites of infection in these patients.”
The results of the study were presented at the ATS 2013 International Conference.
This retrospective, multicenter, cohort study included 7,974 patients from 29 academic and community hospitals. The researchers examined the relationship between 20 anatomic sources of infection and hospital survival, adjusting for predisposing factors including year and source of admission, age, sex, comorbidities, community- vs. hospital-acquired infection andandorganism type. They also adjusted for other potential mediating factors such as Acute Physiologic and Chronic Health Evaluation (APACHE) II score, number of Day 1 organ failures, bacteremia, appropriateness of antibiotic treatment, and adjunct therapy.
After adjustment for these possible confounders, infections in eight anatomic sites were associated with significantly higher chances of survival compared to the lung, including genitourinary infections secondary to hydronephrosis and pyelonephritis, intra-abdominal infection secondary to cholecystitis/cholangitis and enterocolitis/diverticulitis, skin and soft tissue infection secondary to cellulitis/abscess/necrotizing fasciitis/decubitus ulcer, surgical site infection, intravascular catheter-related infection, and other infection sources. Infections related to hydronephrosis were associated with the highest chance of survival.
Infections in four anatomic sites were associated with significantly lower chances of survival (compared to lung): intra-abdominal infection secondary to ischemic bowel, disseminated infections, and central nervous system infections. Infections related to ischemic bowel were associated with the lowest chance of survival.
Further adjustment for the timing of initiation of antibiotic treatment did not significantly alter these relationships.
“Knowing that the source of infection can affect mortality in ICU patients who have septic shock may help guide treatment in these patients,” said Dr. Dodek. “Further research should examine whether targeted treatment of the anatomic source of infection improves outcomes. In addition, these findings support stratification by anatomic source of infection of patients who are enrolled in clinical trials of sepsis treatments.”
American Thoracic Society International Conference May 17-22, 2013 Philadelphia, Pennsylvania
* Please note that numbers in this release may differ slightly from those in the abstract. Many of these investigations are ongoing; the release represents the most up-to-date data available at press time.
Association Between Source Of Infection And Hospital Mortality In Patients Admitted To The Intensive Care Unit Because Of Septic Shock
Type: Scientific Abstract
Category: 04.12 – Sepsis (CC)
Authors: A. Leligdowicz1, M. Norena1, H. Wong1, A. Kumar2, P.M. Dodek1; 1St. Paul’s Hospital and University of British Columbia – Vancouver, BC/CA, 2University of Manitoba – Winnipeg/CA
RATIONALE: Understanding mortality associated with the source of infection in septic shock may inform studies of adjunctive agents that inhibit pro-inflammatory mediators in patients who are at a higher risk of mortality and of de-escalation from broad to narrower-spectrum antimicrobial agents in patients who are at a lower risk of mortality. Uncontrolled local infection leads to a systemic inflammatory response. Therefore, the anatomical source of infection may influence the clinical outcome of septic shock. The purpose of this study was to determine the association between the anatomic source of infection and hospital mortality in patients admitted to the ICU because of septic shock.
METHODS: This was a retrospective, multicenter, cohort study of patients admitted between January 1989 and May 2008 to 29 academic and community hospitals in Canada (n=22), United States (n=6), and Saudi Arabia (n=1). Twenty anatomic sources of infection were selected based on clinical diagnosis and/or site where an organism was isolated. Logistic regression was used to analyze the effect of source of infection on hospital survival, adjusting for predisposing factors (year of admission, source of admission, age, comorbidities, community vs. hospital-acquired infection, organism type) and potential mediators (APACHE II score, number of day 1 organ failures, bacteremia, appropriate antibiotics, adjunct therapy). Cox modeling was used in a subgroup of patients who did not receive antibiotics before the onset of hypotension to determine the association between source of infection and hospital mortality after adjustment for time to initiation of antibiotics.
RESULTS: In the 7,974 patients included, crude hospital mortality was 52.4%. After adjusting for predisposing factors and potential mediators, eight anatomic sites were identified to be significantly associated with higher survival (highest survival for hydronephrosis, odds ratio [OR] 3.8, CI 2.6-5.6, p<0.0001) and four with significantly lower survival (lowest survival for ischemic bowel, OR 0.34, CI 0.26-0.45, p<0.0001). Adjusting for timing of initiation of antibiotics had little impact on these relationships.
CONCLUSIONS: The anatomic source of infection is strongly associated with hospital mortality in patients admitted to the ICU because of septic shock.