Effect of mycophenolate mofetil on kidney graft function and body weight in patients with chronic allograft nephropathy.

Background: Chronic allograft nephropathy (CAN) is the most common cause of late graft loss. A beneficial effect of mycophenolate mofetil (MMF) on CAN was observed, although, due to the loss of body weight (BW) under MMF, serum creatinine (sCr) and reciprocal sCr may be unsuitable markers of graft function.
Methods: In 17 kidney transplant patients with CAN, azathioprine (Aza) was replaced by MMF. The remaining therapy was not changed; specifically, the cyclosporine (CsA) dose was not decreased. The mean values and regression coefficients of reciprocal sCr, CCr, urinary creatinine excretion (uCr x V), proteinuria, BW, blood pressure (BP), serum cholesterol (sChol), and serum triglycerides (sTG) versus time were analyzed 12 months before and after institution of MMF by a paired-comparison t test.
Results: The mean regression coefficient of reciprocal sCr differed significantly before and after conversion to MMF (mean -0.01 +/- 0.01 vs +0.012 +/- 0.029 mg/dL per month), suggesting improved graft function. However, the mean values of BW (74 +/- 15 vs 71 +/- 15 kg, P <.001) and uCr x V (1152 +/- 321 vs 1065 +/- 266 mg per 24 hours, P=.0897) decreased, making the increase in CCr less significant (mean -1.16 +/- 2.69 vs 0.40 +/- 1.79 mL/min per month, P <.05). BP, sChol, sTG, and proteinuria before and after conversion did not differ significantly. Among patients with long-term stable graft function at 36.5 +/- 16.9 months after conversion to MMF there was an almost significant improvement in renal protein excretion.
Conclusions: MMF improved graft function, although this effect was overestimated using reciprocal sCr. Other risk factors, such as BP, sChol, and sTG, showed no significant differences, suggesting that MMF accounted for the improvement in CAN. The course of proteinuria under MMF seems to be of prognostic significance.