Optimizing prognostic prediction in kidney allografts with pre-existing diabetic nephropathy: Combining DN RPS and Remuzzi Grading

Purpose: How to assess diabetic nephropathy (DN) donor kidneys and to what extent they are acceptable are unclear. The predictive capacity of DN renal pathology society (RPS) grade and Remuzzi grade on DN donor kidney prognosis was evaluated and compared. Methods: We conducted a single-center retrospective study including DN (n = 13), standard donor (SD) (n = 802) and expanded criteria donor (ECD) (n = 124) donor kidneys. We also conducted an international multicenter retrospective study included 70 DN donor kidneys reviewed based on DN RPS grade and Remuzzi score, which was the largest DN donor kidney cohort in the world. The graft prognosis including graft survival, post-transplant eGFR and proteinuria were compared between allografts. Multivariate regression was to describe the effect of DN grade and Remuzzi grade on prognosis. Results: The single-center study found lower graft survival, lower one- and two-year eGFR and more severe proteinuria in DN recipients comparing with those of SD and ECD. Furthermore, the international multicenter study did not found high Remuzzi grade (> 4, n = 19) independently associated with worse prognosis. While high DN grade (> IIa, n = 20) associated with worse graft survival (HR = 5.68, p = 0.002), lower two-year eGFR (Coefficient = -22.43, p = 0.002) and worse proteinuria (One-year: OR = 9.13, p = 0.011; Two-year: OR = 6.63, p = 0.030), independent of Remuzzi grade. The high DN grade donor kidneys mainly lost with severe proteinuria. Conclusions: Remuzzi grade alone is insufficient for donor DN assessment. Combining DN RPS grade and Remuzzi grade could be more effective in predicting DN allograft prognosis. DN donor kidneys with RPS grade higher than IIa should be used with caution even with low Remuzzi score.