RenalComplication: MetabolicProteinuria Is a Predictor of Posttransplant Anemia

IntroductionPosttransplant anemia (PTA) involves many factors. Although the link between the hemoglobin (Hb) levels and renal function is known, the relationship between proteinuria and PTA hemoglobin has not been widely explored. The aim of this study was to evaluate whether proteinuria was a predictor of anemia and whether erythropoietin-stimulating agent therapy was a protective factor for kidney damage among transplantation patients.MethodsWe retrospectively examined 144 kidney transplant recipients of mean age 44.4 ± 12.3 years and a mean follow-up period of 40.5 ± 4.6 months. Exclusion criteria were age under 18 years, multiorgan transplantation, proteinuria at 6 months over 1.5 g/d, and transplant failure within the first year. Using regression models, we evaluated the potential predictive power of proteinuria at 6 months after renal transplantation for anemia as expressed by Hb levels at 1 year.ResultsThe frequency of patients with PTA was 38.89% at 1 year, 35.21% at 2 years, and 31.43% at 3 years. Variables with significant correlations with anemia upon univariate analysis were: proteinuria, donor age, acute rejection, estimated glomerular filtration rate, s-creatinine, and salbumin. Upon multivariate regression analysis 24-hour proteinuria and s-albumin remained independent predictors of 1-year PTA. Univariate analysis among the entire cohort showed a significant correlation between 1-year Hb and proteinuria/24 hours at 6 months (P = .007), an observation that was confirmed in the adjusted model along with recipient sex. Patients were then divided into two groups regarding treatment with erythropoiesis stimulating agents (ESA). Multivariate analysis showed that proteinuria (P = .005) was a predictor of Hb only among the group of patients who did no receive erythropoietin, whereas this relationship disappeared among the group treated with ESA.ConclusionsThese results showed that proteinuria at 6 months was a predictor of Hb levels at 1 year. Treatment of transplant patients with ESA may be a protective factor for renal endothelial damage expressed as proteinuria.