Health and economic outcomes of vancomycin-resistant enterococci.
BACKGROUND
The health and economic impact of vancomycin-resistant enterococci has not been quantified.


METHODS
A retrospective matched cohort study was conducted comparing the outcomes of patients with vancomycin-resistant enterococci (cases) with those of control subjects matched for length of hospital stay until inclusion in the cohort, hospital location, and calendar date. The propensity to be a vancomycin-resistant enterococci case was modeled based on patient characteristics, and included in multivariable models to adjust for confounding. Analyses included the following: (1) conditional logistic regression for mortality, surgery, intensive care unit admission, and discharge to long-term care; (2) linear regression for the logarithm of cost; and (3) accelerated failure time model for length of stay.


RESULTS
A total of 233 cases were compared with 647 controls. Groups were similar in age (mean, 62 years), sex (female, 47%), and length of stay before inclusion in the cohort (mean, 8.1 days), but differed in primary diagnosis and comorbidities, past infection or colonization with methicillin sodium-resistant Staphylococcus aureus or Clostridium difficile, and treatment with cephalosporins or metronidazole. These variables were included in the propensity score, which had good to excellent prediction. Outcomes for cases vs controls and adjusted risks (relative risks [RRs]) were as follows: (1) case fatality rate, 17% vs 6% (RR, 2.13; P =.04); (2) length of stay after inclusion in the cohort, 15.1 vs 8.5 days (RR, 1.73; P<.001); (3) hospital costs, $52 449 vs $31 915 (RR, 1.40; P<.001); (4) surgery after inclusion in the cohort, 18% vs 10% (RR, 2.74; P =.001); (5) intensive care unit admission after inclusion in the cohort, 25% vs 14% (RR, 3.47; P<.001); and (6) transfer to an institution, 51% vs 35% (RR, 2.01; P =.001).


CONCLUSIONS
Compared with a matched hospital population, a population with vancomycin-resistant enterococci was associated with severe adverse outcomes: increased mortality, morbidity, and costs.
Carmeli
Yehuda
Y
Division of Infectious Diseases, Tel Aviv Sourasky Medical Center, 6 Weizman St, Tel Aviv 62749, Israel. ycarmeli@caregroup.harvard.edu
Eliopoulos
George
G
Mozaffari
Essy
E
Samore
Matthew
M
D015331:Cohort Studies; D003365:Costs and Cost Analysis; D003428:Cross Infection / Q000188:drug therapy / Q000191:economics / Q000382:microbiology; D016983:Enterococcus / Q000187:drug effects*; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000191:economics / Q000382:microbiology* / Q000401:mortality; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D020713:Vancomycin Resistance