NEPHROLOGY – ORIGINAL PAPER Risk factors for high erythropoiesis stimulating agent resistance index in pre-dialysis chronic kidney disease patients, stages 4 and 5 Ana de Lurdes Agostinho Cabrita • Ana Pinho • Anabela Malho • Elsa Morgado • Marı ´lia Faı ´sca • Hermı ´nio Carrasqueira • Ana Paula Silva • Pedro Lea ˜o Neves Received: 21 February 2010 / Accepted: 5 July 2010 / Published online: 17 July 2010 Ó Springer Science+Business Media, B.V. 2010 Abstract Background/aims Anemia is common in patients with chronic kidney disease (CKD). Recently, the erythropoiesis-stimulating agent/hemoglobin level (ESA/Hb) index emerged as a new factor associated with increased morbidity and mortality in this population. In this study, we evaluated the factors that influence the ESA/Hb index in a pre-dialysis CKD population. Methods Ninety-five patients were evaluated for clinical and laboratory parameters, nutritional status and ESA/Hb index. For comparison, we divided our population into 3 groups: G I—no ESA treatment, G II—patients with ESA/index below 50th percentile and G III—patients with ESA/Hb index above 50th percentile. We performed single and multiple regres- sion models and logistic regression analysis. Results In a multiple regression model, age (t = -3.456, P = 0.001), SGA (t = 2.059, P = 0.047), ferritin (t = 2.386, P = 0.027), Ca 9 P (t = 2.066, P = 0.043), TNF-a (t = 2.673, P = 0.009) and IL-6 (t = 2.939, P = 0.004) independently influenced the ESA/Hb index. At logistic regression analysis, gender, cardiovascular disease and TNF-a were independently associated with ESA/Hb higher than 50th percentile compared to the other patients (R 2 = 0.457). Conclusion In a pre-dialysis population, female gender, cardiovascular disease, malnutrition and inflammation are associated with a higher ESA/Hb index. Keywords Anemia Á Erythropoiesis-stimulating agent resistance Á Inflammation Á Malnutrition Introduction Anemia is an almost universal finding in patients with CKD once the glomerular filtration rate (GFR) has fallen below 30 ml/min/1.73 m 2 [1]. It is primarily due to insufficient production of erythropoietin (Epo) from diseased kidneys, and recombinant Epo has been shown to be useful in correction of anemia in patients with renal failure [2–4]. Anemia and its suboptimal correction have been associated with an increased prevalence of cardiovascular disease, which induces a higher morbidity and mortality in pre-dialysis patients, as well as in patients under renal replacement therapy [5–9]. In many patients with CKD, however, anemia seems to be resistant to ESA treatment despite adequate iron supplementation [10]. Several factors, such as hyperparathyroidism, aluminium intoxication, blood loss, hemoglobinopa- thies and hemolysis, are associated with ESA resistance A. de Lurdes Agostinho Cabrita (&) Á A. Pinho Á A. Malho Á E. Morgado Á M. Faı ´sca Á H. Carrasqueira Á A. P. Silva Á P. L. Neves Servic ¸o de Nefrologia, Hospital de Faro, Rua Lea ˜o Penedo, 8000-342 Faro, Algarve, Portugal e-mail: anadelurdes@lycos.com 123 Int Urol Nephrol (2011) 43:835–840 DOI 10.1007/s11255-010-9805-9