Analysis of Allograft Biopsy Specimens in Renal Transplants With Proteinuria: Is Proteinuria a Culprit of Graft Loss?

Abstract

It has been proposed that proteinuria occurring after renal transplantation may be not only amarker but also a culprit of allograft dysfunction. We retrospectively analyzed the data from 55patients who underwent transplant renal biopsy for proteinuria and/or azotemia occurring beyond1 year after transplantation. Proteinuria was considered as significant when ≥ 30 mg/dL, and theresults of transplant biopsy were categorized according to the Banff 97 classification. Logisticregression was used to estimate odds ratios (OR) for graft loss associated with proteinuria andtransplant pathology. The patients were followed for 86.0 ± 32.8 months after transplantation,and transplant biopsy was performed at 54.1 ± 31.0 months. Proteinuria at 1 year aftertransplantation noted in 29.1% of patients was not significantly associated withgraft loss (OR = 1.94, 95% CI from 0.59 to 6.41). In addition, proteinuria at the time of transplant biopsywas not significantly associated with graft loss.Chronic allograft nephropathy was themost frequent transplant pathology. Only glomerulonephritis was significantly associated withproteinuria at the time of the transplant biopsy. On the other hand, graft loss was significantlyassociated with the presence of proteinuria both at 1 year after transplant biopsy and at the finalfollow-up. These results suggest that posttransplantation proteinuria is an important marker ofgraft dysfunction, but is not predictive of graft loss in biopsy-proven cases. Appropriatemanagement guided by the results of a transplant biopsy may improve the outcome.