Purpose: The aim of this study was to assess the impact of obesity on risk for cytomegalovirus (CMV) infection after kidney transplantation as well as the potential impact of morbid obesity on the effectiveness of CMV prophylaxis in this patient population.

Methods: This study was a retrospective review of patients receiving a kidney transplant between January 2010 and December 2014. Pediatric patients and multi-organ transplants were excluded from the study. Morbidly obese patients were defined as having a BMI of ≥ 35 mg/m². CMV infection was defined as a composite of any level of CMV viremia, CMV syndrome, or CMV disease. Appropriateness of valganciclovir dosing was determined using the Cockcroft-Gault equation for creatinine clearance using patient ideal body weight. Appropriate dosing was defined based on the valganciclovir product labeling dosing of 900 mg daily for patients with a creatinine clearance of ≥ 60 mL/min with dose reductions based on degree of renal dysfunction.

Results: The rate of CMV infections was higher in the morbidly obese patient population with 26% of patient with a BMI ≥ 35 kg/m² developing an episode of CMV viremia, syndrome, or disease compared with 14% of patients with BMI < 35 kg/m². There was a trend toward a higher rate of breakthrough CMV infection while on valganciclovir prophylaxis in the morbidly obese patient group. No difference was seen in the proportion of patients in each group receiving subtherapeutic valganciclovir doses at 1, 3, and 6 months.

Conclusions: Obesity may impact patient risk for development of CMV as well as risk for breakthrough CMV infection while on valganciclovir prophylaxis after kidney transplantation. These results in the absence of a difference in the proportion of under-dosed patients calls into question whether current valganciclovir dosing using creatinine clearance based on ideal body weight is sufficient in a morbidly obese patient population, although further studies are needed to confirm an association.

CITATION INFORMATION: Strout S, Pilch N, Veasey T, Miller R, Fleming J, Meadows H, Mardis C, Mardis B, Baliga P, Chavin K, Taber D. Impact of Morbid Obesity on Breakthrough CMV Infection in Kidney Transplant Recipients. Am J Transplant. 2016;16 (suppl 3).

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