Does additional treatment with fish oil mitigate the side effects of recombinant human erythropoietin in dialysis patients?

Since fish oil has been reported to reduce platelet aggregability, to reduce blood viscosity by increasing red blood cell deformability and to lower blood pressure, we studied the effect of dietary supplementation with fish oil on the occurrence of adverse effects in patients receiving recombinant human erythropoietin (rHuEPO). In a prospective, randomized, double blind cross-over design we studied the effect of daily ingestion of 3 g fish oil versus 3 g corn oil (placebo) for 5 months, with a wash-out period of 3 months in between. Thirty-two dialysis patients newly treated with rHuEPO participated. rHuEP0 was given using a low and slow dose regimen (25 U/kg twice weekly s.c.). Target Hct was 35%. Blood pressure, red blood cell deformability, plasma viscosity, fatty acid composition of plasma phospholipids, and fibrinogen levels were measured at 0, 5, 8 and 13 months. In both groups a stable target Hct (35%) was reached within 3 months. Blood pressure was not significantly different between the groups at any time point. In 4 patients (2 on fish oil and 2 on placebo) antihypertensives had to be increased to regulate blood pressure adequately, whereas shunt occlusion occurred in one patient on placebo. Despite a significant increase in the omega-3 fatty acid content of plasma phospholipids during ingestion of fish oil, no significant changes in red blood cell deformability were observed. Since hypertension and shunt occlusion occurred at rates comparable to those reported in the literature, long-term ingestion of fish oil does not appear to mitigate the side effects of low and slow dose rHuEPO.