Effect of Epoetin Induced Normal Hb on Progression of Nephropathy in Insulin Treated Diabetic Patients with Renal Anaemia

Background and aims: Haemoglobin (Hb) decreases were associated with progression of nephropathy and it has been suggested that normal Hb levels may preserve renal function. Our aim was to investigate if this could be achieved by erythropoietin (EPO).

Methods: A prospective randomized study of treatment with erythropoietin (EPO) was carried out in insulin treated diabetic patients with albuminuria, morning urine albumin > 300 mg/l, and anaemia, Hb < 110 g/l.  EPO was given in order to achieve Hb levels 115 g/l (low) or 130 g/l (normal). The patients were followed for one year and evaluated every third month with timed overnight urine collections, 24 hour blood pressure measurement and glomerular function (GFR) with iohexol clearance.

Results: Twelve patients achieved 115 g/l and seven patients 130 g/l. The median GFR before treatment was 26 (12-50) and 29 (15-53) ml/min/1.73m² (median and min-max, p=NS). The median decrease in GFR per month was faster in the patients with low Hb [- 1.0 (-2.89 to 0.25)] than in the normal Hb level group [-0.08 (-1.08 to 1.16] ml/min/1.73m² per month (median and min-max, p= 0.015). Four patients were started on dialysis (n=2) or died (n=2), all in the low Hb group. Urine human complex (a-1-microglobulin) increased, i.e. proximal tubular function worsened, in the low Hb group with no change in the normal Hb group. Urine albumin, Immunoglobulin G, glycosaminoglycans, collagen IV non-collagenous part (NC1) and Tamm-Horsfall protein did not change in any of the groups. Glycated haemoglobin (HbA_1c) and blood pressure levels were unchanged in both groups.

Conclusions: The present study infers that EPO treatment may preserve both glomerular filtration rate and proximal tubular function. Further studies are needed to confirm our findings.