VRE and VSE Bacteremia Outcomes in the Era of Effective VRE Therapy: A Systematic Review and Meta-analysis

Abstract

BACKGROUND Prior data suggest that vancomycin-resistant Enterococcus (VRE) bacteremia is associated with worse outcomes than vancomycin-sensitive Enterococcus (VSE) bacteremia. However, many studies evaluating such outcomes were conducted prior to the availability of effective VRE therapies. OBJECTIVE To systematically review VRE and VSE bacteremia outcomes among hospital patients in the era of effective VRE therapy. METHODS Electronic databases and grey literature published between January 1997 and December 2014 were searched to identify all primary research studies comparing outcomes of VRE and VSE bacteremias among hospital patients, following the availability of effective VRE therapies. The primary outcome was all-cause, in-hospital mortality, while total hospital length of stay (LOS) was a secondary outcome. All meta-analyses were conducted in Review Manager 5.3 using random-effects, inverse variance modeling. RESULTS Among all the studies reviewed, 12 cohort studies and 1 case control study met inclusion criteria. Similar study designs were combined in meta-analyses for mortality and LOS. VRE bacteremia was associated with increased mortality compared with VSE bacteremia among cohort studies (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.38-2.35; I2=0%; n=11); the case-control study estimate was similar, but not significant (OR, 1.93; 95% CI, 0.97-3.82). LOS was greater for VRE bacteremia patients than for VSE bacteremia patients (mean difference, 5.01 days; 95% CI, 0.58-9.44]; I2=0%; n=5). CONCLUSIONS Despite the availability of effective VRE therapy, VRE bacteremia remains associated with an increased risk of in-hospital mortality and LOS when compared to VSE bacteremia. Infect. Control Hosp. Epidemiol. 2015;37(1):26-35.

Figure 1

Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flowchart of the literature search and study selection.

Figure 2

VRE and VSE bacteremia unadjusted in-hospital mortality risk by study design. Results of included studies for VRE and VSE bacteremia unadjusted in-hospital mortality risk stratified by study design. Abbreviations: 95% CI, 95% confidence interval; SE, standard error; IV, random, inverse-variance, random-effects method.

Figure 3

VRE and VSE bacteremia total hospital LOS mean difference. Results of studies reporting on VRE and VSE bacteremia total hospital LOS. Abbreviations: LOS, length of stay; 95% CI, 95% confidence interval; SE, standard error; IV, random, inverse-variance, random-effects method.

Figure 4

VRE and VSE post-bacteremia total hospital LOS mean difference. Results of studies reporting on VRE and VSE post-bacteremia hospital LOS. Abbreviations: LOS, length of stay; 95% CI, 95% confidence interval; SE, standard error; IV, random, inverse-variance, random-effects method.

Figure 5

Subgroup analysis of VRE and VSE bacteremia un-adjusted in-hospital mortality risk by age, immune status, study site(s), and study quality, for each included cohort study reporting these data. Abbreviations: 95% CI, 95% confidence interval; SE, standard error; IV, random, inverse-variance, random-effects method.

Figure 6

Subgroup analysis of VRE and VSE bacteremia hospital LOS by age, for each included cohort study reporting these data. Abbreviations: LOS, length of stay; 95% CI, 95% confidence interval; SE, standard error; IV, random, inverse-variance, random-effects method.

Figure 7

Asymmetrical funnel plot of VRE and VSE bacteremia in-hospital mortality effect estimates of all included studies.