Chronic progressive renal disease: rate of change of serum creatinine concentration.

The rate of change of the serum creatinine concentrations in 63 patients with chronic progressive renal disease of varied etiology was examined by linear regression analysis using the logarithm or the reciprocal of the serum creatinine concentration versus time. A single straight line was described by one or the other of these relationships in 53 patients. Six patients had an accelerated rate of nephron destruction terminally (two slopes) regardless of the mathematical analysis. The remaining four patients had course changes either due to apparent spontaneous remissions or temporally related to therapy. These data suggest that (functional) nephron loss in chronic progress disease is orderly and mathematically definable. The theoretical implications are that functional nephron loss is either exponential (log Cr) or constant (1/Cr).