Posttransplantation anemia at 12 months in kidney recipients treated with mycophenolate mofetil: risk factors and implications for mortality

Abstract

Although posttransplantation anemia (PTA) is common in the mycophenolate mofetil era, its impact on patient survival is unknown. This retrospective cohort study characterized factors that are associated with PTA 12 mo after transplantation in mycophenolate mofetil-treated kidney recipients and explored whether 12-mo PTA affects outcomes. The records of 626 kidney recipients were examined for presence of anemia (hemoglobin <12 g/dl). Multivariate regression models, fit with covariates that had unadjusted relationships, investigated both risk factors for 12-mo PTA and whether 12-mo PTA contributes to mortality. Anemia prevalence was 72, 40, and 20.3% at 1, 3, and 12 mo, respectively. By multivariate logistic regression, anemia at 3 mo (odds ratio [OR] 10.0; 95% confidence interval [CI] 5.3 to 17.1; P = 0.0001), donor age (OR 1.0; 95% CI 1.1 to 1.3; P = 0.005), and 3-mo creatinine (OR 2.0; 95% CI 1.2 to 3.3; P = 0.044) were associated with 12-mo PTA. The PTA cohort had inferior patient survival (P = 0.02, log rank) and a higher proportion of cardiovascular deaths (6.3 versus 2.2%; P = 0.017) than nonanemic patients. By Cox regression, 12-mo PTA (hazard ratio [HR] 3.0; 95% CI 1.3 to 6.7; P = 0.009), 12-mo creatinine (HR 1.3; 95% CI 1.1 to 1.4; P = 0.008), age at transplantation (HR 1.1; 95% CI 1.1 to 1.2; P = 0.004), and hepatitis C seropositivity (HR 2.8; 95% CI 1.1 to 7.0; P = 0.03) were associated with mortality. There was no interaction between 12-mo PTA and serum creatinine. In conclusion, 12-mo PTA is associated with an increased risk for patient death. The presence of anemia 3 mo after kidney transplantation is a major determinant of 12-mo PTA. PTA in kidney recipients therefore should be defined by its persistence or occurrence beyond the third posttransplantation month.