Evaluation of eight methods for estimating creatinine clearance in men.

Eight methods for estimating creatinine clearance (CLcr) were compared in 65 men with serum creatinine concentrations (SCr) less than or equal to 1.5 mg/dL (group 1) and 65 men with SCr greater than 1.5 mg/dL (group 2). All patients had SCr values that did not fluctuate by more than +/- 10% for two weeks before and two weeks after measurement of CLcr. For each patient, predictions of CLcr by each of eight currently used formulas were compared with measured CLcr values; both regression analysis and predictive error analysis were used. Group 1 patients ranged in age from 32 to 64 years (mean, 53), weighed from 48 to 105 kg (mean, 73), and were from 63 to 79 inches in height (mean, 69). Group 2 patients ranged from 26 to 63 years of age (mean, 53), weighed from 34 to 141 kg (mean, 80), and were from 63 to 76 inches in height (mean, 70). Measured CLcr values ranged from 29.8 to 197 mL/min in group 1 and from 2.8 to 118 mL/min in group 2. Ranges of SCr values were 0.7-1.5 mg/dL (mean, 1.1) in group 1 and 1.6-7.1 mg/dL (mean, 2.8) in group 2; the formula of Cockcroft and Gault, which uses age, body weight, and SCr, had the highest correlation and the greatest accuracy in group 1, whereas the formula of Jelliffe, which uses body surface area and SCr, had the highest correlation and the greatest accuracy in group 2. Estimation of creatinine clearance can be improved by identification and use of the formula that is best suited to a specific patient population.