- Poster presentation
- Open Access
Validation of the Cockroft-Gault formula for estimation of creatinine clearance in the critically ill population
© BioMed Central Ltd 2006
- Published: 21 March 2006
- Glomerular Filtration Rate
- Peritoneal Dialysis
- Creatinine Clearance
Estimation of creatinine clearance by the Cockroft-Gault (CG) formula is used in daily practice to calculate the glomerular filtration rate (GFR) in critically ill patients. This formula was derived from a cohort of noncritically ill patients and has not been validated against a standard measurement of the GFR such as 24-hour urine creatinine clearance in the critically ill patient.
To quantify the discrepancy in GFR estimated by the CG formula and 24-hour urine creatinine clearance.
A prospective cohort study was conducted in 50 adult patients in a mixed medical-surgical ICU. Inclusion criteria were ITU stay >48 hours and indwelling urinary catheter. Exclusion criteria were age <18 years, pregnancy, hemodialysis or peritoneal dialysis, urine output <400 ml/day and patients receiving cimetidine, ranitidine, cefoxitin, trimethoprim or diuretics. We estimated the GFR by the CG formula and measured the GFR by the 24-hour urine creatinine clearance. A Bland and Altman plot was used to find the percentage difference between the paired observations. The association between the two methods was measured by the product moment correlation coefficient.
We conclude that CG formula has a strong correlation with the measured GFR but is not a reliable measure and overestimates the GFR in the critically ill population.