Effect of cytomegalovirus prophylaxis with acyclovir on renal transplant survival

It is recognized that cytomegalovirus (CMV) infection in transplant recipients may lead to graft loss. Prophylaxis with acyclovir has therefore gained widespread acceptance, but the debate on whether this intervention improves long term graft survival continues. All patients who received renal grafts at the National Renal Transplant Centre, Dublin, between January 1992 and December 1999 were retrospectively analyzed. During this time period, patients who were CMV positive and/or had received grafts from CMV-positive donors were administered prophylactic oral acyclovir 800 mg thrice daily, adjusted for calculated creatinine clearance, from the first day post-transplantation. This treatment was continued for three months unless the graft failed or the patient developed CMV disease or died. Graft and patient outcomes were compared in recipients who received acyclovir with those who did not. Over the study period, 935 patients received renal transplants in our center, of whom 487 were administered acyclovir. The incidence of CMV disease was 3.3 cases per 100 patients per annum in those who required prophylaxis. Despite prophylaxis, graft outcomes were found to be significantly worse (p value < 0.001) in the group that qualified for acyclovir. We conclude that acyclovir provides incomplete protection from the negative impact of CMV on graft survival.