Predicting creatinine clearance and renal drug clearance in obese patients from estimated fat-free body mass

Existing methods for predicting creatinine clearance provide accurate estimates for normal-weight patients but not for patients who are obese. Studies into this problem began with an animal model of obesity, the obese overfed rat. Mean creatinine clearance was found to vary in direct proportion to fat-free body mass, determined in both obese and normal animals. The relevance of this observation to renal function in humans was evaluated by analyzing published studies reporting creatinine clearance and creatinine excretion rates in obese and normal persons. Measured creatinine clearance correlated well with estimated fat-free body mass (r = 0.772, p