The Conundrum of Managing Anemia in Chronic Kidney Disease Patients on Dialysis with Associated Hemoglobinopathies- Perspective from a Single Nephrology Centre in North –Eastern India

Abstract

Anemia is a common complication in chronic kidney disease (CKD) and has been associated with a reduced quality of life [1] as well as worse survival [2] and increased morbidity and mortality [3]. The prevalence of anemia is more severe as the estimated glomerular filtration rate (eGFR) declines and is 8.4% at stage 1 to 53.4% at stage 5. Similar data is observed in a more recent paper by the CKD Prognosis Consortium which also observed an increased prevalence of anemia among diabetic patients, independent of eGFR and albuminuria [4]. In CKD patients, EPO deficiency starts early in the course of CKD and appears initially, when eGFR falls below 30ml/min/1.73m2, this deficiency becomes more severe [5]. This absolute EPO deficiency can be caused by a decrease EPO production and /or errors in EPO sensing. CKD produces an alteration in oxygen delivery to the kidneys and results in adaptation of renal tissue to consume less oxygen and subsequent maintenance of normal tissue oxygen gradient. As a consequence, prolyl-hydroxylase domain (PHD) enzymes which regulates HIF activity remain active, the HIF heterodimer is not formed and the EPO gene is not activated [6]. Some CKD patients may also present with a functional EPO deficiency or EPO resistance, where normal range. EPO levels co-exist with low hemoglobin levels indicating a blunted bone marrow response to endogenous and exogenous EPO. Mechanisms hypothesized for EPO resistance include presence of pro-inflammatory cytokines thought to induce apoptosis and down regulation of expression of EPO receptor.