Objectives: Recent evidence of a high incidence of proteinuria among de novo sirolimus-based regimens has been reported among renal transplant patients at short-term follow-up. We report on long-term evaluation of proteinuria among patients maintained on such regimen.
Materials and methods: Between May 2001 and January 2003, 132 patients received a renal allograft from a living donor and were randomized to 2 groups (steroids/sirolimus/tacrolimus, n=65) and (steroids/sirolimus/mycophenolate mofetil, n=67): Both received basiliximab induction. Retrospective review of those patients was performed, 5 years posttransplant with particular emphasis on the incidence of proteinuria.
Results: The 5-year incidence of proteinuria was 29.2% and 38.8% among sirolimus/tacrolimus and sirolimus/mycophenolate mofetil group. Single DR-matched patients (P = .016) and the incidence of acute rejection (P = .039) were associated with significantly higher incidence of proteinuria. Moreover, the presence of mesangial matrix increased (P = .015), and glomerulosclerosis (P = .014), in 1-year protocol biopsies, was found to have a positive predictive value for current and future incidences of proteinuria. Proteinuria was found to be associated with significant inferior graft outcome. Recurrent original kidney disease, de novo glomerulopathy, and acute transplant glomerulopathy were responsible for early cases of nephrotic range proteinuria (first 2 years), while cases presented later were attributed to chronic allograft nephropathy.
Conclusions: Proteinuria has become a recognized, serious event of primarily sirolimus-treated renal transplants patients, which is most probably of glomerular origin. It has been shown that proteinuria exerts a bad prognostic effect upon graft function and subsequent graft survival at 5-year follow-up.