title: Impact of empiric weight-based vancomycin dosing on nephrotoxicity and mortality in geriatric patients with methicillin-resistant Staphylococcus aureus bacteraemia.
abstract: OBJECTIVE
  Few studies have evaluated the effect of vancomycin dosing on the health outcomes in geriatric patients. Data are needed to determine whether higher vancomycin dosing strategies are more effective in geriatric patients and/or lead to excessive rates of adverse events.
  
  
  METHODS
  This study used a subset of patients aged ≥65 years from a multicentre, retrospective, cohort study of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Patients received ≥ 48 h of empiric vancomycin between 1 July 2002 and 30 June 2008. We compared the incidence of nephrotoxicity and in-hospital mortality in patients who received guideline-recommended dosing (at least 15 mg/kg/dose) to patients who received lower dosing. Multivariable generalized mixed-effect models were constructed to determine independent risk factors for nephrotoxicity and in-hospital mortality.
  
  
  CONCLUSIONS
  Half of the cohort (46% of 92 patients) received guideline-recommended dosing. Empiric use of weight-based dosing did increase the percentage of patients achieving a vancomycin trough ≥ 15 mg/L (57% vs. 42%). Nephrotoxicity occurred in 32% of patients and 26% died during their hospitalization. Guideline-recommended dosing was not associated with significant changes in nephrotoxicity (OR 1·13; 95% CI 0·40-3·19) or in-hospital mortality (OR 1·14; 95% CI 0·41-3·18) in the multivariable analysis.
  
  
  CONCLUSIONS
  In this study of geriatric patients, guideline-recommended dosing was not associated with significant changes in nephrotoxicity or mortality. As 40% of the patients who received guideline-recommended dosing failed to achieve a target vancomycin trough of ≥ 15 mg/L, future studies should focus on dosing strategies to increase target attainment rate.
authors.affiliation: Department of Pharmacy Practice, Texas Tech University Health Sciences Center, School of Pharmacy, Dallas, TX, USA; Department of Clinical Sciences, University of Texas Southwestern, Dallas, TX, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: Hall
authors.forename: A T
authors.initials: AT
authors.lastname: Blaszczyk
authors.forename: K A
authors.initials: KA
authors.lastname: Thompson
authors.forename: S D
authors.initials: SD
authors.lastname: Brouse
authors.forename: C A
authors.initials: CA
authors.lastname: Giuliano
authors.forename: C R
authors.initials: CR
authors.lastname: Frei
authors.forename: N A
authors.initials: NA
authors.lastname: Forcade
authors.forename: E M
authors.initials: EM
authors.lastname: Mortensen
authors.forename: T
authors.initials: T
authors.lastname: Bell
authors.forename: R J
authors.initials: RJ
authors.lastname: Bedimo
authors.forename: C A
authors.initials: CA
authors.lastname: Alvarez
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D001835:Body Weight; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology / Q000209:etiology; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification; D015999:Multivariate Analysis; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D014640:Vancomycin / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin
keywords: antibiotics; evidence-based medicine; mortality; nephrotoxicity; obesity; vancomycin