Cockcroft and Gault formula

It is difficult to obtain an accurate measure of renal function in patients with cirrhosis. A number of studies have shown that they tend to have low serum creatinine levels. This has been explained by a reduced muscle mass in cirrhotic patients and a reduced conversion of creatine to creatinine [10]. The calculation of creatinine clearance using the Cockcroft and Gault formula is also inaccurate in predicting GFR in these patients because it uses the serum creatinine level (which may be falsely low) and body weight in the calculation, which is likely to be inflated due to the presence of ascites [12]. The measured creatinine clearance, based on urinary excretion of creatinine, should theoretically be more accurate, even in patients with reduced muscle mass or impaired creatinine synthesis. However, it has been shown that this also overestimates the GFR because of an increased fractional tubular secretion of creatinine in cirrhotic patients, particularly those with reduced GFR [10]. 

The Cockcroft and Gault formula is one of the earliest, and perhaps most widely used, of these formulas. The... 

In practice, there may be little to choose between the Cockcroft and Gault formula and the more recently described MDRD equation,and which is chosen will be... 

Calculated Clearance. The mathematical relationship between plasma creatinine and GFR can be improved by correcting for the confounding variables that make that relationship nordinear. More than 25 different formulas have been derived that estimate GFR using plasma creatinine corrected for some or all of gender, body size, race, and age. These may produce a better estimate of GFR than serum creatinine alone. Indeed the National Kidney Foundation of the United States has recommended that such estimates should be used in preference to serum creatinine, and that either the Cockcroft and Gault or Modification of Diet in Renal Disease (MDRD) formula should be used in adults. The Schwartz and Counahan-Barratt formulas are recommended for use in children. 

They observed that the MDRD equation provided more accurate assessment of GFR than either the Cockcroft and Gault equation or measured creatinine clearance. The MDRD formula has several advantages (1) it was developed and validated in a large population, (2) it was developed with a population that included both European-Americans and African-Americans, (3) it does not require patient weight, (4) it was validated against an iothalamate clearance estimate... 

It is also important to remember that renal function deteriorates with age and with Mrs RP about to commence capecitabine, it is necessary to estimate her current creatinine clearance. Based on the Cockcroft-Gault formula quoted above ... 

Calculate Mr WD s renal function using the MDRD equation and the Cockcroft-Gault formula. 

A commonly used surrogate marker for actual creatinine clearance is the Cockcroft-Gault formula, which employs creatinine measurements and a patient s age and weight to predict the clearance. It is named after the scientists who first published the formula. The equation is popular because it is easy to calculate. 

Quadri KHM, Bemardini J, Greenberg A, et al. Assessment of renal function during pregnancy using a random urine protein to creatinine ratio and Cockcroft-Gault formula. Am J Kidney Dis 1994 24 416-420. 

Harmoinen A, Lehtimaki T, Korpela M, Turjanmaa V, Saha H. Diagnostic accuracies of plasma creatinine, cystatin C, and glomerular filtration rate calculated by the Cockcroft-Gault and Levey (MDRD) formulas. Clin Chem 2003 49 1223-5. 

Pierrat A, Gravier E, Saunders C, et al. Predicting GFR in children and adults a comparison of the Cockcroft-Gault, Schwartz, and modification of diet in renal disease formulas. Kidney Int 2003 64 1425-1436. 

Calvert formula for dose modifications Dose (mg) = target AUC x (CLcr -E 25) CIcr calculated using Cockcroft-Gault equation note that the calculated dose is total dose, not dose per m body surface area Bone marrow recovery may require 6-8 weeks postadministration not a vesicant vein irritation and facial flushing may be related to alcohol vehicle... 

---