Poor Outcomes Associated with Neutropenia after Kidney Transplantation: Analysis of United States Renal Data System

Background. Posttransplant neutropenia (PTN) is relatively common after kidney transplantation, and may result in a reduction of immunosuppression, which may precipitate acute rejection. Granulocyte colony-stimulating factors (GCSF) have been used to treat PTN, although outcomes associated with use of this medication in this population are unknown.Methods. In a retrospective cohort of 41,705 adult Medicare primary patients transplanted from January 2001 to June 2006, we assessed Medicare claims for neutropenia, leukopenia, and GCSF use, respectively. Outcomes included allograft loss and death.Results. There were 6043 (14.5%) patients with claims for PTN. Factors associated with PTN included female gender, Caucasian ethnicity, ischemic heart disease, donor cytomegalovirus positive, deceased donor, expanded donor criteria, delayed graft function, elevated panel reactive antibody, higher human leukocyte antigen mismatch, and later year of transplant. Thymoglobulin induction, tacrolimus, and mycophenolate mofetil were also associated. PTN was less frequent among patients with congestive heart failure, recipient cytomegalovirus positive, and interleukin-2 induction. PTN was associated with increased risk of allograft loss (adjusted hazard ratio, 1.59; 95% confidence interval, 1.43-1.76; P<0.001) and death (adjusted hazard ratio, 1.74; 95% confidence interval, 1.59-1.90; P<0.001). Of the 6043 patients with PTN, 740 (12.2%) received GCSF. Patients who received GCSF had a lower risk of death on unadjusted analysis, but this only trended towards significance after adjustment.Conclusions. Neutropenia after renal transplantation is common and is associated with an increased risk of allograft loss and death. GCSF was used in 12% of cases and did not increase risk of allograft loss. Strategies to avoid PTN and greater use of GCSF may be indicated to prevent graft loss and death.