Relationship between tacrolimus blood levels and covid-19 pandemic in kidney transplant recipients

Purpose: The novel coronavirus 2019 infection (COVID-19) caused a pandemic, prompting Tokyo, Japan, to restrict on the free movement of people in March 2020. Kidney transplant recipients are at high risk for critical COVID-19 due to chronic immunosuppression and coexisting conditions. For the follow-up of kidney transplant recipients during this pandemic, the number of hospital visits or use remote counseling should be reduced to minimize the risk of infection. However, the management of kidney transplant recipients during the COVID-19 pandemic is uncertain. Methods: This single-center retrospective observational study included 980 patients who, more than a year previously, had undergone kidney transplantation and were taking extended-release tacrolimus once a day, with a target trough level of 4 to 6 ng/ml. We evaluated the effects of coronavirus pandemic on clinical outcomes such as tacrolimus blood level, renal function, and rejection in kidney transplant recipients, comparing pandemic data with non-pandemic data obtained between September 2019 and August 2020 in our hospital. Results: Comparing pandemic data with non-pandemic data, the mean interval between hospital visits was 5.5±2.6 vs. 7.3±4.5 weeks (P=2.68×10-14). Serum Cr levels and rejection rates after kidney transplant showed no significant differences between both groups. There were no significantly differences in the coefficient of variation (CV) in tacrolimus blood levels, the rate of changes in oral medication, and the rate of deviation from the target trough level during the pandemic. Conclusions: In kidney transplant recipients, blood levels of tacrolimus were maintained at target trough levels during the COVID-19 pandemic.