Chronic progressive renal failure. Rate of progression monitored by change of serum creatinine concentration.

The rise of serum creatinine levels during were renal failure progressing to end-stage renal disease was studied in 30 children. In 20 patients the rise was a steady one and followed a mathematical model, best expressed by the regression line calculated from reciprocal values. Ten patients had widely fluctuating values that did not fit any of the available mathematical models; however, in three patients, the curve had two slopes. The initially slow rate of progression changed to a more rapid, steady rise when a creatinine level of 2 to 3 mg/dL was reached. Therefore, in 23 of 30 patients, the time at which a serum creatinine values of 10 mg/dL would be reached could be predicted with acceptable accuracy based on this calculation or using a graphic plot. In the terminal phase of renal failure, the serum creatinine value progressed from 7 to 10 mg/dL in less than four months in 80% of the cases.