Accuracy of valganciclovir dosing following kidney transplantation and its impact on clinical outcomes.

Valganciclovir is widely used as prophylaxis against cytomegalovirus (CMV) infection following solid organ transplantation. However, valganciclovir requires dose adjustment based on kidney function. This retrospective observational study at a London kidney transplant center explored the accuracy of valganciclovir dosing in the first 3 months following transplantation and its impact on clinical outcomes. Data for adult kidney transplant recipients (KTRs) receiving valgancivloir prophylaxis between 2017 to 2019 was analyzed. The primary outcome was the difference between the prescribed and optimum valganciclovir dose (calculated by creatinine clearance) on days 10-92 after surgery. Secondary outcomes included associations between valganciclovir dosing with CMV DNAemia, cytopenias and rejection. For the 90 KTRs included, the valganciclovir dose was optimum for 51%, underdosed for 31% and overdosed for 18% of the study period. Significant associations were shown for underdosing and CMV DNAemia (B = 2.88, SE = 1.14, p=0.01, 95% CI [1.90,166.1]) as well as overdosing and neutropenia (B = 2.29, SE 0.99, p=0.02, 95% CI [1.42,68.71]). This study highlights the difficulty in optimally dosing valganciclovir in KTRs post-operatively and importantly shows significant associations between suboptimal dosing and clinical outcomes.