Characterization of Cytomegalovirus Viremia in Renal Transplant Recipients

Kidney transplantation, while improving outcomes for patients with end-stage renal disease, comes with a risk of potentially life-threatening infections such as infection with cytomegalovirus (CMV), a virus associated with allograft rejection, organ dysfunction, and increased mortality.

To characterize whether the choice and dose of immunosuppressant therapy and the duration of antiviral prophylaxis after transplant are associated with the incidence of CMV viremia.

This study was a retrospective review of all kidney-only transplant recipients at the authors' centre from 2012 to 2016, with a minimum 1 year of follow-up. Patients with CMV viremia (defined as serum CMV viral load greater than 1000 IU/mL) were compared with patients who did not have viremia to investigate potential demographic and treatment-related risk factors.

A total of 653 patients were included in the study, of whom 161 (25%) met the criteria for CMV viremia. In univariate analysis, patients with CMV viremia had older age (55 versus 53 years, p = 0.038) and lower mean body weight (75 versus 79 kg, p = 0.015); in addition, the CMV viremia group included larger proportions of patients with Asian descent (40% [64/161] versus 21% [104/492]) and donor-positive/recipient-negative CMV serostatus (29% [47/161] versus 14% [70/492]). With respect to immunosuppressant therapy, patients with CMV viremia more frequently received antithymocyte globulin (ATG) induction (50% [80/161] versus 28% [138/492], p < 0.001) and received a higher weight-based cumulative ATG dose (mean 4.5 versus 4.1 mg/kg, p = 0.038). The multivariate analysis retained use of ATG, cumulative dose of ATG, Asian descent, and CMV serostatus as risk factors for CMV viremia. No statistically significant differences were found for the maintenance immunosuppressant dosing or duration of antiviral prophylaxis.

Use of ATG for induction and higher weight-based dose of ATG were associated with an increased risk of CMV viremia. In addition, a component of race may also be involved, with patients of Asian descent being at higher risk. No differences were found in the maintenance dose of immunosuppression or the duration of antiviral prophylaxis.