1838. The effect of inadequate initial antimicrobial treatment on mortality in critically ill patients with bloodstream infections
Session: Poster Abstract Session: Treatment of HAIs/Antimicrobial Resistant Infections
Saturday, October 10, 2015
Room: Poster Hall
Background: Hospital mortality rates are substantially higher in critically ill patients with bloodstream infections relative to their uninfected counterparts.  Given that patient mortality may be higher if appropriate treatment is delayed, we sought to determine the effect of inadequate initial treatment on mortality in critically ill patients with bloodstream infections. 

Methods: A retrospective cohort study was conducted across 13 intensive care units (ICUs) in Canada.  We recruited 100 consecutive patients with bloodstream infection from each participating ICU.   Inadequate initial treatment was defined as the lack of receipt of at least 1 dose of an antimicrobial(s) to which the causative pathogen(s) was susceptible within 1 day of initial blood culture.  A random effects multivariable logistic regression model was used to evaluate whether inadequate treatment was associated with hospital mortality, accounting for patient and pathogen characteristics as well as ICU clustering.  Interaction terms were added to examine whether the association varied by genus of the pathogen(s).

Results: Among 1,197 patients, 266 (22%) received inadequate initial treatment and 478 (40%) died.  The unadjusted mortality risk was higher among those that received initial inadequate versus adequate treatment (135/266 [51%] vs 341/924 [37%], p<0.001).  After adjustment, there was no association between inadequate initial treatment and mortality among bacteremic patients (Odds Ratio (OR): 0.99, 95% Confidence Interval (CI) 0.68 – 1.44).  Candidemic patients receiving inadequate initial treatment had more than three times the odds of mortality compared to patients receiving adequate treatment (OR: 3.44, 95% CI: 1.24 – 9.54).  Findings were robust to exclusion of early deaths and patients who received no antibiotic treatment, and to using a 2 day window for defining initial treatment.

Conclusion: Inadequate initial treatment, although common, did not explain the high mortality experienced by critically ill, bacteremic patients in our study.  Conversely, inadequate initial treatment was an important risk factor for mortality in the subgroup of candidemic patients.  Further exploration of opportunities to improve the receipt of prompt, effective treatment is warranted in this high risk group.

Rachel Savage, MSc1,2, Robert Fowler, MD, MSc3,4, Sean Bagshaw, MD, MSc5, Deborah Cook, MD, MSc6, Peter Dodek, MD, MHSc7,8, Richard Hall, MD9,10, Anand Kumar, MD11, François Lamontagne, MD12, François Lauzier, MD, MSc13, John Marshall, MD14,15, Claudio Martin, MD, MSc16, Lauralyn Mcintyre, MD, MSc17, John Muscedere, MD18,19, Steven Reynolds, MD20, Asgar Rishu, MBBS4, Tom Stelfox, MD, PhD21 and Nick Daneman, MD, MSc2,22,23, (1)Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada, (2)Sunnybrook Health Sciences Centre, Toronto, ON, Canada, (3)Department of Medicine, University of Toronto, Toronto, ON, Canada, (4)Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, (5)Critical Care Medicine, University of Alberta, Edmonton, AB, Canada, (6)Department of Medicine, Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, ON, Canada, (7)Division of Critical Care Medicine, University of British Columbia, Vancouver, BC, Canada, (8)Centre for Health Evaluation and Outcome Sciences, St Paul's Hospital, Vancouver, BC, Canada, (9)Division of Critical Care Medicine, Department of Anesthesiology, Dalhousie University, Halifax, NS, Canada, (10)Capital District Health Authority, Halifax, NS, Canada, (11)Section of Critical Care Medicine, Health Sciences Centre/St. Boniface Hospital, University of Manitoba, Winnipeg, MB, Canada, (12)Centre De Recherche Clinique Étienne-Le Bel, Université de Sherbrooke, Sherbrooke, ON, Canada, (13)Centre De Recherche Frqs Du Centre Hospitalier Affilié Universitaire De Québec, Axe Traumatologie - Urgence - Soins Intensifs, Division De Soins Intensifs Adultes, Départements De Médecine Et D'anesthésiologie, Université Laval, Québec, QC, Canada, (14)Critical Care Medicine, St. Michael's Hospital, Toronto, ON, Canada, (15)Department of Surgery, University of Toronto, Toronto, ON, Canada, (16)Department of Medicine, Western University, London, ON, Canada, (17)Division of Critical Care, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada, (18)Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada, (19)Department of Medicine, Queen's University, Kingston, ON, Canada, (20)Department of Medicine, University of British Columbia, Vancouver, BC, Canada, (21)Department of Critical Care Medicine, Institute of Public Health, University of Calgary, Calgary, AB, Canada, (22)Division of Infectious Diseases & Clinical Epidemiology, University of Toronto, Toronto, ON, Canada, (23)Institute for Clinical Evaluative Sciences, Toronto, ON, Canada

Disclosures:

R. Savage, None

R. Fowler, None

S. Bagshaw, None

D. Cook, None

P. Dodek, None

R. Hall, None

A. Kumar, None

F. Lamontagne, None

F. Lauzier, None

J. Marshall, None

C. Martin, None

L. Mcintyre, None

J. Muscedere, None

S. Reynolds, None

A. Rishu, None

T. Stelfox, None

N. Daneman, None

Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.