The Effect of Tacrolimus Trough Variability on Kidney Transplant Outcomes

Purpose Variability in tacrolimus levels has been associated with increased rejection, graft loss, and de novo donor-specific antibody (dnDSA) development in kidney transplant recipients (KTRs); however, limited data on alemtuzumab induction or infection exist. We sought to determine the impact of tacrolimus variability in KTRs on dnDSAs, graft outcomes, and infections 3 years posttransplant after alemtuzumab induction. Methods Adult KTRs from January 1, 2013, to December 31, 2017, receiving alemtuzumab and tacrolimus-based immunosuppression at a single center were included. Tacrolimus variability was calculated using coefficient of variability (CV), and high CV was defined as ≥30%. Graft and infectious outcomes were assessed between high and low CV groups. Results Two hundred fourteen KTRs were included. The median tacrolimus CV from 0 to 3 months and from 3 to 12 months was 28.1% and 25.8%, respectively. Recipients with high CV had decreased glomerular filtration rate at 3 and 12 months (67.7 ± 35.48 vs 80.7 ± 29.3, P = .01 and 70.9 ± 35.4 vs 83.3 ± 30.2, P = .015). High CV was also associated with increased cytomegalovirus viremia and disease (19.6% vs 9.3%, P = .046 and 6.4% vs 17.9%, P = .015). No difference in biopsy-proven acute rejection, survival, or dnDSA development at 3 years was observed. Conclusions High tacrolimus variability was associated with significantly reduced graft function and increased cytomegalovirus viremia and disease but not biopsy-proven acute rejection, survival, or dnDSA development.