Kidney Week

Abstract: SA-PO483

Use of Body Surface Area Corrected GFR results in Inappropriate Valganciclovir Dosing in Kidney Transplant Recipients

Session Information

• Transplantation: Balancing Rejection and Infection
  November 04, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Transplantation

• 1702 Transplantation: Clinical and Translational

Authors

• Paul, Rohan Singh, University of Pittsburgh Medical Center, Starzl Transplant Institute, Pittsburgh, Pennsylvania, United States

Rohan Singh Paul,

• Puttarajappa, Chethan M., University of Pittsburgh Medical Center, Starzl Transplant Institute, Pittsburgh, Pennsylvania, United States

Chethan M. Puttarajappa,

• Hariharan, Sundaram, University of Pittsburgh Medical Center, Starzl Transplant Institute, Pittsburgh, Pennsylvania, United States

Sundaram Hariharan,

Background

Clinicians generally use the MDRD or CKD-EPI equations to gauge renal function, which normalize GFR to a body surface area (BSA) of 1.73 m². We hypothesized that since absolute GFR is rarely measured and used, prophylactic valganciclovir is being dosed inappropriately in certain renal transplant recipients which may predispose to leukopenia and/or CMV infection.

Methods

This cross-sectional study included 225 renal transplant recipients from UPMC who were transplanted from January 1, 2013 to December 31, 2015. MDRD reported GFR was converted to absolute GFR. Patients were categorized into BSA tertiles (low BSA < 1.73 m²; middle BSA: 1.73-2.09 m²; high BSA > 2.09 m²). The appropriateness of valganciclovir dose among these groups at three months post-transplantation was determined and compared using Chi-squared test. The point prevalence of leukopenia (WBC < 3500 × 10³/mm³) among the dosing categories was analyzed using One-way ANOVA. The incidence of PCR confirmed CMV infection was compared using Chi-squared test.

Results

The study population consisted of 138 (61%) males and 87 (39%) females. Analysis of valganciclovir dosing across the BSA tertiles found no significant difference based on normalized GFR (P = 0.811), but a significant difference based on absolute GFR, with a trend towards overdosing with low BSA and underdosing with high BSA (P < 0.001). There was no difference in the point prevalence of leukopenia across the dosing categories (P = 0.819). There was no difference in the incidence of CMV infection within 100 days post-transplantion as there were zero infections in this period. There was a signficant difference in the incidence of CMV infection 100-400 days post-transplantation with a higher rate seen with higher BSA (P = 0.0468).

Conclusion

We conclude that normalized GFR leads to inappopriate valganciclovir dosing in a large subset of kidney transplant recipients.
This did not translate into a higher point prevalence of leukopenia in those receiving supratherapeutic doses. However there was a higher incidence CMV infection in the 100-400 days post-transplantation in patients with a higher BSA. The observed valganciclovir underdosing in this BSA group is suspected to be at play. We therefore propose that absolute GFR be routinely used for valganciclovir dosing in kidney transplant recipients.