Cystatin C-Guided Vancomycin Dosing in Critically Ill Patients: A Quality Improvement Project

Am J Kidney Dis. 2017 May;69(5):658-666. doi: 10.1053/j.ajkd.2016.11.016. Epub 2017 Jan 25.


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.

Study design: 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.

Setting & participants: 3 medical and surgical ICUs at a single tertiary medical center.

Quality improvement plan: During January 2012 to October 2013, vancomycin was dosed according to eCLcr using 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-cys using the CKD-EPI equation (intervention arm).

Outcome: Steady-state initial goal vancomycin trough concentration achievement.

Measurements & 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.

Limitations: Nonrandomized, incomplete algorithm compliance.

Conclusions: A vancomycin dosing nomogram based on eGFRcr-cys significantly improved goal trough achievement compared to eCLcr among ICU patients with stable kidney function. Further studies are warranted to characterize the relationship between use of cystatin C-guided dosing and clinical outcomes.

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.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Acute Kidney Injury / epidemiology*
  • Administration, Intravenous
  • Aged
  • Aged, 80 and over
  • Algorithms*
  • Anti-Bacterial Agents / administration & dosage*
  • Anti-Bacterial Agents / blood
  • Bacterial Infections / drug therapy*
  • Creatinine / blood*
  • Critical Illness*
  • Cystatin C / blood*
  • Drug Dosage Calculations
  • Drug Monitoring
  • Female
  • Glomerular Filtration Rate*
  • Humans
  • Intensive Care Units
  • Length of Stay
  • Male
  • Middle Aged
  • Prospective Studies
  • Quality Improvement
  • Vancomycin / administration & dosage*
  • Vancomycin / blood


  • Anti-Bacterial Agents
  • Cystatin C
  • Vancomycin
  • Creatinine