Program Schedule

Greater Hospital-Complexity and Case-Volume are Associated with Lower Mortality among Patients with Staphylococcus aureus Bacteremia

Session: Poster Abstract Session: Approach to Clinical Infections
Friday, October 10, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
  • IDWeek 2014 poster final.pdf (532.0 kB)
  • Background:       Prior studies have examined hospital-level variation in outcomes for patients hospitalized with common non-infectious conditions, such as myocardial infarction and heart failure.  However, little is known about hospital-level variation in outcomes for serious infections.  We used a nationwide microbiology database in Veterans Affairs (VA) Healthcare System to quantify hospital-level variation in Staphylococcus aureus bacteremia (SAB) outcomes, and to explore associations between outcomes and hospital characteristics. 

    Methods:              This was a retrospective cohort study of patients admitted to VA hospitals with first episode of community-onset SAB (positive culture within 48 hours of admission) between 2003 and 2010. Patient characteristics and all-cause 30-day mortality were obtained from VA databases; hospital characteristics were from VA organizational surveys.  We used hierarchical logistic regression to calculate risk-adjusted mortality for each hospital, and to evaluate associations between hospital characteristics and patient-level mortality. Patient-level variables included demographics, comorbidities, year of admission, prior hospitalization, methicillin susceptibility of culture isolate, vital signs, and laboratory tests at the time of admission.  

    Results:                 Analyses included 27,380 patients in 122 hospitals.  Overall crude mortality was 16.0%, and ranged from 6.8% to 30.2% across hospitals.  After adjusting for patient characteristics (i.e. "case-mix") hospital-level mortality ranged from 8.8% to 22.4% (Figure).  Mortality was lower among patients admitted to hospitals with larger case volumes [>60/year vs. <15/year: OR 0.70 (0.56-0.86)], higher ICU complexity [complex ICU vs. no ICU: OR 0.47 (0.24-0.93)], and academic affiliations [OR: 0.70 (0.53-0.94)].   Hospital characteristics were more strongly associated with patient mortality than was methicillin susceptibility of the isolate (MRSA vs. MSSA: OR 1.13 (1.05-1.21).

    Conclusion:         Greater hospital-complexity, case-volume, and academic affiliation are associated with lower mortality among patients with SAB. Further study is needed to identify modifiable hospital characteristics and to direct quality-improvement efforts.

    Description: Macintosh HD:Users:michgoto:Desktop:Plot.jpg

    Michihiko Goto, MD1,2, Marin Schweizer, PhD3, Kelly Richardson, PhD4, Eli Perencevich, MD, MS, FIDSA, FSHEA5, Mary Vaughand-Sarrazin, PhD4 and Michael Ohl, MD, MSPH1, (1)Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, (2)VA National Quality Scholars Program, Iowa City VA Health Care System, Iowa City, IA, (3)Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, (4)Iowa City VAMC, Iowa City, IA, (5)Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA


    M. Goto, None

    M. Schweizer, None

    K. Richardson, None

    E. Perencevich, None

    M. Vaughand-Sarrazin, None

    M. Ohl, None

    Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

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