Chronic allograft nephropathy and nephrotic range proteinuria
While the association between post-transplant nephrotic range proteinuria (PTx-NP) and chronic allograft nephropathy (CAN) has been described, the factors that determine graft survival in such patients are unclear. We retrospectively identified 30 patients with biopsy-proven CAN who presented with PTX-NP between 1988 and 2002. Patients were stratified into two groups according to PTX-NP onset: <1 yr vs. >1 yr post-transplantation. Both groups were comparable with respect to the degree of renal dysfunction (serum creatinine 4.3 +/- 2.5 mg/dL vs. 3.4 +/- 1.5 mg/dL) and proteinuria (4.7 +/- 1.6 gm/d vs. 5.8 +/- 3 gm/d). After a mean follow-up of 14 months post-biopsy, 87% of patients had lost their grafts in both groups (89% vs. 83%, p = NS). Overall, patients with serum creatinine 2 mg/dL (75% vs. 4%, Fisher Exact Probability p = 0.0038). Using Kaplan-Meier estimate, the 5-yr graft survival rate was 100% for patients with serum creatinine 2 mg/dL (p = 0.06). The magnitude of proteinuria beyond 3 gm/d did not influence graft survival. One-half of the patients (n = 15) received therapy with angiotensin converting enzyme inhibitors (ACEI). Graft survival, however, was not different between the patients who received ACEI compared with the patients who did not receive ACEI (13% vs. 13%). PTx-NP related to CAN was associated with poor allograft survival, irrespective of the time of onset of presentation, especially when renal function was reduced at the time of biopsy.