Clearance of vancomycin during continuous infusion in Intensive Care Unit patients: correlation with measured and estimated creatinine clearance and serum cystatin C

Vancomycin (VAN) dosing requires adjustment to renal function, which is often estimated using the Cockcroft–Gault formula; however, its precision is poor in Intensive Care Unit (ICU) patients. VAN clearance (CLVan) during continuous infusion was prospectively determined in 25 ICU patients [14 male, 11 female; age range 31–82 years; body mass index (BMI) 16.5–41.5 kg/m2; Acute Physiology and Chronic Health Evaluation (APACHE) II score at admission 8–36; creatinine clearance 25–195 mL/min] and its correlation with measured creatinine clearance (CLCrea), estimated creatinine clearance using the Cockcroft–Gault formula (CLCG) and estimated glomerular filtration rate according to Hoek's formula based on serum cystatin C (GFRHoek) was investigated. The correlation between CLVan and CLCrea was very good (r2 = 0.88), but it was rather poor with CLCG (r2 = 0.37) and was acceptable with GFRHoek (r2 = 0.70). For VAN dose adjustments in ICU patients, determination of cystatin C may be an interesting and practical alternative to measured CLCrea, whereas the Cockcroft–Gault formula should be used with caution.