RESUMEN
Erythropoietin resistance index calculation has been used as a tool to evaluate anemia response to erythropoietin therapy. Very little has been reported in its use when using darbepoetin and factors influencing in Arab patients. Darbepoetin resistance index (DRI) was calculated in all our patients using darbepoetin. This was correlated to demographic, clinical, and laboratory parameters. Of the 250 patients, 40.4% were diabetic, 71.1% on hemodialysis, and 28.6% on hemodiafiltration), 23.9% with PermCaths (PC), and 76.1 % with arteriovenous fistula (AVF). The mean DRI was 10.96 ± 12.9 I. Females had 45% higher DRI than males (P = 0.005), and patients with PC had a 66% higher DRI than those with AVF (P = 0.029). Patients with Vitamin D level below the 50th percentile had 55.9% higher DRI than those above it (P = 0.05). DRI was negatively correlated with age (P = 0.018), dialysis vintage (P = 0.039), interdialytic weight gain P = 0.007), Vitamin D level, and serum albumin (P = 0.005) and positively correlate with parathyroid hormone (PTH) level (P = 0.000). No impact was seen by the mode of dialysis, being diabetic, using anti-hypertensive therapy, body mass index, Kt/V, serum iron, total iron binding capacity, transferrin saturation, ferritin, C-reactive protein, Ca, or P. DRI in our Arab patients was comparable to erythropoietin resistance indices reported in other communities. Higher DRI was observed in females, PC users, lower serum albumin, lower Vitamin D, and shorter dialysis vintage. A negative correlation existed between DRI and age, dialysis vintage, interdialytic weight, and serum albumin and a positive correlation with PTH level.