Association of posttransplantation proteinuria with allograft loss in transplant kidney biopsy-proven recipients

Hong, Sang Mo; Choi, Nak Won; Yoon, Jai Hoon; Lee, Chang Hwa; Kim, Gheun Ho; Park, Moon Hyang; Kang, Chong Myung

Abstract

BACKGROUND: Previous studies reported a poor prognosis in patients with persistent proteinuria later in the posttransplantation course, suggesting that posttransplantation proteinuria is a marker for graft failure. This study was undertaken to elucidate the role of proteinuria after renal transplantation in the pathogenesis and outcome of allograft dysfunction in transplant biopsy-proven recipients.
METHODS
We retrospectively analyzed the data from 55 patients who underwent transplant renal biopsy for proteinuria and/or azotemia occurring beyond 1 year after transplantation. Proteinuria was considered as significant when >or=30 mg/dL, and the results of transplant biopsy were categorized according to the Banff 97 classification. Logistic regression was used to estimate odds ratios (OR) for graft loss associated with proteinuria and transplant pathology.
RESULTS
The patients were followed for 86.0 +/- 32.8 (mean +/- SD) months after transplantation, and transplant biopsy was performed at 54.1 +/- 31.0 months. Proteinuria at 1 year after transplantation was noted in 29.1% of the patients, and it was not significantly associated with graft loss (OR=1.94, 95% CI 0.59-6.41). In addition, proteinuria at the time of transplant biopsy was not significantly associated with graft loss, and none of each category of transplant pathology was significantly associated with graft loss. Chronic allograft nephropathy was the most frequent transplant pathology, and only glomerulonephritis was significantly associated with proteinuria at the time of transplant biopsy. On the other hand, graft loss was significantly associated with the presence of proteinuria both at 1 year after transplant biopsy and at the final follow-up.
CONCLUSION
These results suggest that posttransplantation proteinuria is an important marker of graft dysfunction but may not be predictive of graft loss in biopsy-proven cases. Appropriate management guided by the results of transplant biopsy may improve the outcome.