title: Variant hemoglobin phenotypes may account for differential erythropoiesis-stimulating agent dosing in African-American hemodialysis patients.
abstract: African-American patients with end-stage renal disease have historically lower hemoglobin concentrations and higher requirements of erythropoiesis-stimulating agent (ESA). While disparities in health-care access may partially explain these findings, the role of variant hemoglobin, such as sickle trait, has not been investigated. To clarify this, we evaluated 154 African-American patients receiving in-center hemodialysis with available hemoglobin phenotyping. The primary exposure was any abnormal hemoglobin variant and the primary outcome of higher-dose ESA was defined as a dose of 6500 or more units per treatment. Logistic regression assessed the association between variant hemoglobin and higher-dose ESA. Covariates included age, gender, diabetes, iron parameters, intravenous iron dose, parathyroid hormone, albumin, phosphorus, body mass index, vascular access type, hospitalization/missed treatments, smoking status, alcohol abuse, and gastrointestinal bleeding. Of 33 patients with variant hemoglobin, 24 had HbAS and 9 had HbAC. Univariate odds of higher-dose ESA among those with hemoglobin variants were twice that of those with the normal HbAA phenotype (odds ratio 2.05). In multivariate models, the likelihood of higher-dose ESA had an odds ratio of 3.31 and the nature of this relationship did not change in Poisson regression or sensitivity analyses. Hence, our findings may explain, in part, the difference in ESA dosing between Caucasians and African-Americans with end-stage renal disease but await further study.
authors.affiliation: Division of Nephrology and Hypertension, Department of Medicine, UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. Electronic address: vimal_derebail@med.unc.edu.
authors.forename: Vimal K
authors.initials: VK
authors.lastname: Derebail
authors.affiliation: Division of Nephrology and Hypertension, Department of Medicine, UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Nachman
authors.affiliation: Division of Hematology and Oncology, and Program in Hemostasis and Thrombosis, Department of Medicine, Carolina Cardiovascular Biology Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Nigel S
authors.initials: NS
authors.lastname: Key
authors.affiliation: Renal Research Institute, New York, New York, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Ansede
authors.affiliation: Division of Nephrology and Hypertension, Department of Medicine, UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Falk
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Wayne D
authors.initials: WD
authors.lastname: Rosamond
authors.affiliation: Division of Nephrology and Hypertension, Department of Medicine, UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Abhijit V
authors.initials: AV
authors.lastname: Kshirsagar
mesh_terms: D001741:Black or African American / Q000235:genetics; D000368:Aged; D000755:Anemia, Sickle Cell / Q000097:blood / Q000188:drug therapy* / Q000208:ethnology / Q000235:genetics; D003430:Cross-Sectional Studies; D054796:Drug Dosage Calculations; D004351:Drug Resistance / Q000235:genetics; D005260:Female; D005838:Genotype; D006397:Hematinics / Q000009:adverse effects*; D006444:Hemoglobin C / Q000235:genetics / Q000378:metabolism*; D006445:Hemoglobin C Disease / Q000097:blood / Q000188:drug therapy* / Q000208:ethnology / Q000235:genetics; D006451:Hemoglobin, Sickle / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000208:ethnology / Q000628:therapy*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D006435:Renal Dialysis; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D006397:Hematinics; D006451:Hemoglobin, Sickle; D006444:Hemoglobin C