Empiric weight-based vancomycin in intensive care unit patients with methicillin-resistant Staphylococcus aureus bacteremia.
BACKGROUND
Previous studies were conducted in all hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia to determine safety and effectiveness of guideline-recommended, weight-based dosing of vancomycin. In these studies, it was observed that severely ill patients (Pitt bacteremia score ≥4 or intensive care unit [ICU] patients) were at an increased risk of mortality and/or nephrotoxicity. Therefore, a subanalysis of the effect of guideline-recommended vancomycin dosing on in-hospital mortality and nephrotoxicity in ICU patients with MRSA bacteremia was conducted.


METHODS
This multicenter, retrospective, cohort study was conducted in a subset of ICU patients from a previous MRSA bacteremia study. Patients were ≥18 years old and received ≥48 hours of empiric vancomycin from July 1, 2002, to June 30, 2008. The incidence of nephrotoxicity and in-hospital mortality was compared in patients who received guideline-recommended dosing (at least 15 mg/kg per dose) to patients who received non-guideline-recommended dosing of vancomycin. Multivariable generalized linear mixed-effects models were constructed to determine independent risk factors for in-hospital mortality and nephrotoxicity.


RESULTS
Guideline-recommended dosing was received by 34% of patients (n = 137). Nephrotoxicity occurred in 35% of patients receiving guideline-recommended dosing and 39% receiving non-guideline-recommended dosing (P = 0.67). In-hospital mortality rate was 24% among patients who received guideline-recommended dosing compared with 31% for non-guideline-recommended dosing (P = 0.40). Guideline-recommended dosing was not associated with nephrotoxicity (odds ratio: 1.10; 95% confidence interval: 0.43-2.79) or in-hospital mortality (odds ratio: 0.54; 95% confidence interval: 0.22-1.36) in the multivariable analysis.


CONCLUSIONS
Guideline-recommended dosing of vancomycin in ICU patients with MRSA bacteremia is not significantly associated with nephrotoxicity or in-hospital mortality. However, the 7% absolute difference for in-hospital mortality suggests that larger studies are needed.
Department of Pharmacy Practice (CAA, KAT, SDB, RGH), Texas Tech University Health Sciences Center, School of Pharmacy, Dallas, Texas; Departments of Clinical Sciences (CAA, EMM, RGH) and Internal Medicine (EMM, RJB), University of Texas Southwestern, Dallas, Texas; Department of Pharmacy Practice (CAG, KKH), Texas Tech University Health Sciences Center, School of Pharmacy, Amarillo, Texas; Wayne State University, Eugene Applebaum College of Pharmacy and Health Sciences (CAG), Wayne State University (CAG), Department of Pharmacy Practice; OU Medical System (KAT), Department of Pharmacy; Mission Regional Medical Center (NAF), Department of Pharmacy; University of Kentucky Healthcare (SDB), Department of Pharmacy; Detroit, Michigan; OU Medical System (KAT), Oklahoma City, Oklahoma; Division of Pharmacotherapy (CRF, NAF), University of Texas, Austin, Texas; Mission Regional Medical Center (NAF), Mission, Texas; University of Kentucky Healthcare (SDB), Lexington, Kentucky; Section of General Internal Medicine (EMM), VA North Texas Health Care System, Dallas, Texas; Department of Internal Medicine (TB), Texas Tech University Health Sciences Center, School of Medicine, Amarillo, Texas; and Texas Tech University Health Sciences Center (NMT), School of Pharmacy, Dallas, Texas.
Carlos A
CA
Alvarez
Christopher A
CA
Giuliano
Krystal K
KK
Haase
Kathleen A
KA
Thompson
Christopher R
CR
Frei
Nicolas A
NA
Forcade
Sara D
SD
Brouse
Eric M
EM
Mortensen
Todd
T
Bell
Roger J
RJ
Bedimo
Nolan M
NM
Toups
Ronald G
RG
Hall
D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D016470:Bacteremia / Q000175:diagnosis / Q000188:drug therapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D008875:Middle Aged; D017410:Practice Guidelines as Topic / Q000592:standards*; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000188:drug therapy*; D014640:Vancomycin / Q000494:pharmacology / Q000627:therapeutic use*
D000900:Anti-Bacterial Agents; D014640:Vancomycin