There is limited data on the potential nephrotoxicity of sirolimus (SRL) and tacrolimus (TAC) in combination.Methods.
We reviewed the course of 97 kidney transplant patients treated with SRL and reduced-dose TAC. Conversion from SRL to mycophenolate mofetil (MMF) was prescribed in a minority (n=19) for various nonrenal side effects. We compared outcomes of converted patients to those remaining on TAC/SRL (n=78).Results.
TAC levels were increased in converters (P=0.009). Rejection rates were similar between groups over 18 months (21% vs. 16%, p=ns). Serum creatinine (Cr) and MDRD glomerular filtration rate (GFR) were similar between groups at nadir and six-months, but at 18 months the percent change from six-month Cr was +17% in non-converters vs. −10% in converters (P=0.004 for the difference). The difference in GFR between groups at 18 months was also significant (P=0.01). By multivariate analysis, only conversion to MMF was associated with a greater percent change in Cr from 6 to 18 months (P=0.015). Conversion to MMF also correlated with higher GFR at 18 months independent of rejection, delayed graft function, and ethnicity.Conclusions.
Conversion from TAC/SRL to TAC/MMF led to improved renal function despite increased TAC exposure after conversion.