Mild renal dysfunction is sufficient to induce erythropoietin deficiency in patients with unexplained anaemia.

Current guidelines suggest that anaemia due to erythropoietin deficiency almost exclusively occurs with creatinine concentrations of at least 177 mu mol/l or above. The aim of this prospective case control pilot study was to evaluate whether borderline renal function or mild renal dysfunction with creatinine concentrations well below 177 mu mol/l is sufficient to induce inadequate erythropoietin secretion. Patients referred for work-up of otherwise unexplained anaemia with mildly abnormal creatinine concentrations (104-129 mu mol/l; study group: eight patients) and patients referred for work-up or therapy of other diseases who also presented with anaemia but normal creatinine levels (<100 mu mol/l; control group: nine patients matched for gender, age and degree of anaemia) were included. All but two patients in the control group had bone marrow biopsies to exclude other pathologies. Mild renal dysfunction las evidenced by creatinine concentrations between 100 and 140 mu mol/l, median concentration 112 mu mol/l) was found to be sufficient to induce inadequate erythropoietin secretion. The physiologic hemoglobin-dependent erythropoietin regulation demonstrated in the control group was abolished in the study group. Patients with mild renal dysfunction and unexplained anaemia should be investigated for erythropoietin concentration. If the erythropoietin concentration is found to be inadequate for the degree of anaemia, substitution therapy should be considered. (C) 2000 Published by Elsevier Science B.V. All rights reserved.