Influence of range of renal function and liver disease on predictability of creatinine clearance

Abstract

Several formulas for predicting creatinine clearance (Ccr) are used for adjusting drug dosages but limited data are available on their accuracy in patients with significant renal impairment or concurrent disease. In 103 patients 144 Ccr were measured and results compared using 4 separate predictive methods. Of 9 common diseases in these patients, liver disease was associated with a large (P < 0.02) prediction error (overprediction). After data from 8 patients with liver disease were removed there was good overall correlation between predicted and measured Ccr (r2 = 0.91 for each method), but only 2 of the methods (1 and 4) were consistently accurate in all ranges of renal function. Methods for predicting Ccr should not be used in patients with liver disease.