Evolution of glomerular filtration rate, renal injury markers, anemia, and angiotensin blockers use after change from calcineurin inhibitors to sirolimus in transplant patients with neoplasia versus chronic allograft nephropathy

Abstract

Background: The change from calcineurin inhibitors (CNI) to sirolimus (SRL) is a safe alternative in transplant patients with neoplasia (NEO) whereas the results of conversion for chronic allograft nephropathy (CAN) are controversial, depending on the histologic score, degree of proteinuria, and glomerular filtration rate (GFR). Our aim in this study was to compare GFR, proteinuria, albuminuria, blood pressure (BP) effects, and anemia after switching to sirolimus (SRL) among renal transplant recipients with CAN versus NEO.

Methods: Fifty-five kidney transplant recipients with conversion from CNI to SRL owing to CAN or NEO were analyzed for the variables at 6 months before, at the time of, and at 6 months and 1, 2, and 3 years after the switch to SRL.

Results: There were no differences between CAN and NEO in the slope of estimated GFR (mL/min/1.73 m(2) by Cockcroft-Gault formula) at 1 year (-5.5 vs 3.7; P = .007) and at 2 years (-3.86 vs -10.3; P = .01). The values of proteinuria (mg/24 h/1.73 m(2)) before (665 ± 136 vs 329 ± 69; P = .036) as well as at 1 (1,122 ± 306 vs 863 ± 190; P = .478) and at 2 years after conversion (1,360 ± 430 vs 457 ± 154; P = .045) showed some significant differences, as did the use of both antiangiotensin agents, angiotensin-converting enzyme inhibitor and angiotensin receptor blocker at the moment of switch (35% vs 0%; P = .005) at 1 year (69% vs. 6% P = .02) and at 2 years (67% vs 28%; P = .047). There were no differences in graft survival (log rank: P = .515). By logistic regression analysis, the best covariate associated with GFR >45 mL/min at 2 years was GFR >60 mL/min at the moment of switch to SRL (odds ratio, 1.33; 95% confidence interval, 1.002-1.74).

Conclusions: The evolution of renal damage was more important in the CAN group requiring greater use of 2 angiotensin antagonists for control of proteinuria. We probably need histologic and serologic biomarkers to show which patients with CAN will show a bad evolution after the change to SRL.