EPO and anemia (phenotype): To determine the important variables related to increase in haemoglobin, 8 variables; 2 qualitative variables (presence of anaemia and iron supplemantaion) and 6 quantitative variables (ESA dose, erythropoietin resistance index, C-reactive protein, intact parathyroid hormone, erythrocyte creatine content and reticulocyte) were used in the multivariate logistic analysis.