[Comorbidity, anemia and response to erythropoiesis stimulating agents in chronic hemodialysis]

Patients treated with haemodialysis have a high prevalence of co-morbidity that induces a elevate mortality risk. On the other hand, these patients have anaemia whose treatment is based in erythropoiesis stimulating agents. To date there are not enough studies to determine if co-morbidity alters erythropoietin response and the relationship between co-morbidity, response to treatment of anaemia and resistance to erythropoiesis-stimulating agents.

We have the following objectives: i) to study the prevalence of associated diseases in patients treated with haemodialysis in our Hospital Unit and to evaluate the co-morbidity Charlson Index, ii) to know the degree of anaemia control, dose and response to erythropoiesis-stimulating agents, and iii) to determine the relationship with co-morbidity and anaemia treatment.

We designed a retrospective study in stable haemodialysis treated patients. We calculated the Charlson co-morbidity index adjusted to age and we analysed levels of haemoglobin in the 6 months before study, dose of erythropoiesis-stimulating agents and its resistance index defined as doses of erythropoiesis-stimulating agents/weight (kg)/week/haemoglobin (g/dL). The different variables included in Charlson index were considered as independent variables and the index to repose to erythropoiesis-stimulating agents as a dependent variable, using bivariant and multivariate statistical analysis.

We included 58 patients (31 males and 27 females), median age of 69.5 years (range 24-88), mean haemodialysis 83.7 months. Mean Charlson index was 7.4 +/- 2.8 (range 2-13). Comorbidity-age Charlson index was 2 in 3.4% of patients; 10.3% had 3 or 4 points; 43.2% between 5 and 7 and 43,1% 8 or more. Mean haemoglobin levels was 11,7+/-1,2 g/dL. Mean erythropoiesis-stimulating agents dose was 163.7+/-114.5 IU/kg/week and resistance index 14.1+/-9.7. Most of patients (57%) had a IRE value higher than 10. Fourteen patients (24%) had haemoglobin less than 11 g/dL, and 3 of them (5.1%) received erythropoiesis-stimulating agents more than 300 IU/kg/week. Nine subjects (15.5%) was treated with high dose of erythropoiesis-stimulating agents (>300 IU/kg/week): 3 of them had Hb>or=11 g/dL and 6 had Hb<11 g/dL. We did not found that the intensity of Charlson index is related with the degree of anaemia control or response to erythropoiesis-stimulating agents.

Although the co-morbidity index is high and the response to erythropoiesis-stimulating agents is inadequate. In our study there is not relationship between these conditions.