title: Cystatin C-Guided Vancomycin Dosing in Critically Ill Patients: A Quality Improvement Project.
abstract: BACKGROUND
  The aim of the study was to determine whether a vancomycin dosing algorithm based on estimated glomerular filtration rate from creatinine and cystatin C levels (eGFRcr-cys) improves target trough concentration achievement compared to an algorithm based on estimated creatinine clearance (eCLcr) in critically ill patients.
  
  
  METHODS
  This prospective quality improvement project evaluated intensive care unit (ICU) patients started on intravenous vancomycin using one of 2 different strategies. Dosing regimens were selected and implemented after an individualized goal trough range was established (10-15 or 15-20mg/L). Steady-state goal trough achievement was compared between treatment arms with and without adjustment for potential confounders.
  
  
  METHODS
  3 medical and surgical ICUs at a single tertiary medical center.
  
  
  METHODS
  During January 2012 to October 2013, vancomycin was dosed according to eCLcrusing the Cockcroft-Gault formula (control arm). During December 2013 to May 2015, a multidisciplinary quality improvement team implemented a novel vancomycin dosing algorithm according to eGFRcr-cysusing the CKD-EPI equation (intervention arm).
  
  
  RESULTS
  Steady-state initial goal vancomycin trough concentration achievement.
  
  
  RESULTS
  More patients in the intervention arm (67 of 135 [50%]) achieved therapeutic trough vancomycin levels than in the control arm (74 of 264 [28%]; OR, 2.53; 95% CI, 1.65-3.90; P<0.001). Improved trough achievement was maintained even after adjustment for age, sex, APACHE (Acute Physiology and Chronic Health Evaluation) III score, fluid balance, baseline CLcr, surgical admission diagnosis, presence of sepsis, and goal trough concentration range (adjusted OR, 2.79; 95% CI, 1.76-4.44; P<0.001). Clinical outcomes were similar between groups.
  
  
  CONCLUSIONS
  Nonrandomized, incomplete algorithm compliance.
  
  
  CONCLUSIONS
  A vancomycin dosing nomogram based on eGFRcr-cyssignificantly improved goal trough achievement compared to eCLcramong ICU patients with stable kidney function. Further studies are warranted to characterize the relationship between use of cystatin C-guided dosing and clinical outcomes.
authors.affiliation: Department of Pharmacy, Mayo Clinic, Rochester, MN. Electronic address: erin.frazee@gmail.com.
authors.forename: Erin
authors.initials: E
authors.lastname: Frazee
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN; Division of Epidemiology, Mayo Clinic, Rochester, MN.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Rule
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
authors.forename: John C
authors.initials: JC
authors.lastname: Lieske
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN; Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Kianoush B
authors.initials: KB
authors.lastname: Kashani
authors.affiliation: Department of Pharmacy, Mayo Clinic, Rochester, MN.
authors.forename: Jason N
authors.initials: JN
authors.lastname: Barreto
authors.affiliation: Division of Infectious Diseases, Mayo Clinic, Rochester, MN.
authors.forename: Abinash
authors.initials: A
authors.lastname: Virk
authors.affiliation: Department of Pharmacy, Mayo Clinic, Rochester, MN.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Kuper
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Dierkhising
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN.
authors.forename: Nelson
authors.initials: N
authors.lastname: Leung
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology*; D061605:Administration, Intravenous; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood; D001424:Bacterial Infections / Q000188:drug therapy*; D003404:Creatinine / Q000097:blood*; D016638:Critical Illness; D055316:Cystatin C / Q000097:blood*; D054796:Drug Dosage Calculations; D016903:Drug Monitoring; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D058996:Quality Improvement; D014640:Vancomycin / Q000008:administration & dosage* / Q000097:blood
chemical_list: D000900:Anti-Bacterial Agents; D055316:Cystatin C; D014640:Vancomycin; D003404:Creatinine
keywords: Vancomycin; antimicrobial dose regimen; creatinine; critically ill patients; cystatin C; dosing algorithm; estimated glomerular filtration rate (eGFR); goal trough concentration; intensive care unit (ICU); methicillin-resistant Staphylococcus aureus (MRSA); pharmacokinetics; quality improvement project; renal function; sepsis