title: Bayesian Estimation of Vancomycin Pharmacokinetics in Obese Children: Matched Case-Control Study.
abstract: OBJECTIVE
  The study objective was to compare different body size descriptors that best estimate vancomycin Vd and clearance (CL).
  
  
  METHODS
  Patients between 3 months and 21 years old who received vancomycin for ≥48 hours from 2003 to 2011 were evaluated in this matched case-control study. Cases had body mass index in the ≥85th percentile; controls were nonobese individuals who were matched by age and baseline serum creatinine (SCr). Using a 1-compartment model with first-order kinetics, Bayesian post hoc individual Vd and CL were estimated.
  
  
  RESULTS
  Analysis included 87 matched pairs with 389 vancomycin serum concentrations. Median ages were 10.0 (interquartile range [IQR], 4.8-15.2) years for cases (overweight and obese children) and 10.2 (IQR, 4.5-14.8) years for controls (normal-weight children). Median weights were 44.0 (IQR, 23.4-78.1) kg for cases and 31.3 (IQR, 16.8-47.1) kg for controls. Mean (SD) for the baseline SCr values were also similar between the groups: 0.51 (0.22) (IQR, 0.34-0.67) mg/dL and 0.48 (0.20) (IQR, 0.30-0.60) mg/dL for the cases and controls, respectively. Actual weight and allometric weight (ie, weight(0.75)) were used in the final model to estimate Vd and CL, respectively. The mean Vd and CL, based on weight, for cases were lower than controls by 0.012 L/kg and 0.014 L/kg/h, respectively.
  
  
  CONCLUSIONS
  In obese children, actual weight and allometric weight are reasonable, convenient estimations of body fat to use for estimating vancomycin Vd and CL, respectively. However, these pharmacokinetic differences between obese children and those with normal weights are small and may not likely to be clinically relevant in dose variation.
authors.affiliation: University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, La Jolla, California; Miller Children׳s Hospital of Long Beach, Long Beach, California. Electronic address: jenle@ucsd.edu.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Le
authors.affiliation: University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, La Jolla, California.
authors.forename: Edmund V
authors.initials: EV
authors.lastname: Capparelli
authors.affiliation: University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, La Jolla, California.
authors.forename: Uzra
authors.initials: U
authors.lastname: Wahid
authors.affiliation: University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, La Jolla, California.
authors.forename: Yi Shuan S
authors.initials: YS
authors.lastname: Wu
authors.affiliation: Rady Children's Hospital of San Diego, San Diego, California.
authors.forename: Gale L
authors.initials: GL
authors.lastname: Romanowski
authors.affiliation: Miller Children׳s Hospital of Long Beach, Long Beach, California.
authors.forename: Tri M
authors.initials: TM
authors.lastname: Tran
authors.affiliation: Miller Children׳s Hospital of Long Beach, Long Beach, California.
authors.forename: Austin
authors.initials: A
authors.lastname: Nguyen
authors.affiliation: University of California, San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences and School of Medicine, La Jolla, California; Rady Children's Hospital of San Diego, San Diego, California.
authors.forename: John S
authors.initials: JS
authors.lastname: Bradley
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000097:blood / Q000493:pharmacokinetics*; D001499:Bayes Theorem; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D056865:Ideal Body Weight; D007223:Infant; D008297:Male; D008954:Models, Biological; D009765:Obesity / Q000097:blood*; D050177:Overweight / Q000097:blood; D012044:Regression Analysis; D012189:Retrospective Studies; D014640:Vancomycin / Q000097:blood / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin
keywords: Staphylococcus aureus; antibiotics; children; obesity; pediatrics; pharmacokinetics; vancomycin