Anemia with erythropoietin deficiency occurs early in diabetic nephropathy

OBJECTIVE - The normochromic normocytic anemia of erythropoietin (EPO) defi ciency is recognized in advanced renal failure but not in early renal disea se. The aim of this study was to determine whether anemia with EPO deficien cy is found in type 1 diabetic patients with diabetic nephropathy in the ab sence of advanced renal failure and to compare them with patients with nond iabetic renal disease of similar severity. RESEARCH DESIGN AND METHODS - A total of 27 type 1 diabetic patients with d iabetic nephropathy (DN), defined as having persistent proteinuria (mean 1, 086 mg/day [CI 120-5,190]), a serum creatinine less than or equal to 180 mu mol/l, and retinopathy, were compared with 26 nondiabetic patients with gl umerulonephritis (GN) and persistent proteinuria (1,874 mg/day [349-5,005]) . The Hb concentration, red cell indexes, and serum EPO levels were measure d, and other causes for the anemia. were excluded. The EPO values were comp ared with a normal reference range obtained from nondiabetic patients with a microcytic anemia. The DN patients were tested for signs of diabetic peri pheral and autonomic neuropathy. RESULTS - We round that 13 of the 27 DN patients were anemic (Hb 10.6 +/- 0 .9 g/dl) in marked contrast to none or the GN patients (Hb 13.7 +/-: 1.4 g/ dl, P < 0.005). In the DN group, serum EPO concentrations failed to increas e in response to anemia compared with the response seen in patients with mi crocytic anemia. Thus, the anemia of the DN group was associated with EPO d eficiency. The anemic DN patients showed evidence of more severe proteinuna and diabetic neuropathy than the nonanemic DN patients. CONCLUSIONS - Anemia associated with EPO deficiency can occur early in DN b efore the onset of advanced renal failure, but does not normally occur in n ondiabetic renal disease of similar severity. The pathogenesis requires elu cidation.