Erythropoietin (EPO) has been suggested to improve metabolism and also cognition, but human studies are scarce. This randomised controlled trial aimed to investigate whether EPO treatment influences body composition and fat and glycated haemoglobin (HbA1c) and fasting glucose, and whether these changes would be associated with previous observed cognitive benefits of EPO.
In total, 84 non-obese patients with treatment-resistant unipolar depression or bipolar disorder in remission were randomised to 8 weekly EPO (40,000 IU) or saline (NaCl 0.9%) infusions in a double-blind, parallel-group design. Patients underwent dual X-ray absorptiometry scans at baseline and week 14 (6 weeks after treatment completion). Cognitive measures were assessed and fasting levels of cholesterol, lipoprotein fractions, triacylglycerides, glucose and HbA1c were obtained at baseline, week 9 and follow-up week 14.
In total, 79 patients had complete pre- and post-treatment data (EPO: N=40, saline: N=39). EPO had no cumulative effect on body composition and markers of fat metabolism. The EPO-treated group exhibited significantly lower HbA1c levels after 8 weeks treatment [F(1, 80)=8.51, p=0.005], however, 6 weeks after treatment termination a significantly higher fasting glucose levels [F(1, 79)=5.85, p=0.02] and HbA1c levels [F(1, 79)=5.85, p=0.02] were seen. The latter increase in HbA1c was further significantly correlated with a better cognitive outcome on verbal memory (r=0.25, p=0.03).
Repeated EPO infusions had no cumulative effect on body composition in this cohort of patients with affective disorders, however, EPO modulated HbA1c and fasting glucose and this was associated with patients’ improvement of verbal memory.