Lack of renal effects of fish oil administration in patients with advanced cirrhosis and impaired glomerular filtration

The treatment of renal failure in cirrhotic patients with ascites remains unsatisfactory. Recent studies have shown that the dietary supplementation with fish oil improves the renal function of normal subjects, as well as that of patients with renal failure of different etiologies. We have investigated the renal effects of a daily supplementation for 1 month of 12 g fish oil (27% C20:5 n-3 eicosapentanoic acid [EPA], and 23% C22:6 n-3 docosahexanoic acid [DHA]) in a prospective study of cirrhotic patients with ascites, nine with normal renal function (group 1) and eight with renal failure (glomerular filtration rate [GFR] <60 mL/min, group 2). Compliance with the dietary regimen was confirmed by fatty acid chromatography that showed increased plasma concentration of EPA (from 1.5 ± 0.7% to 3.7 ± 0.8%, P = .024, in group 1; and from 0.53 ± 0.3% to 2.9 ± 0.8%, P = .03, in group 2) and of DHA (from 2.1 ± 0.4% to 3.4 ± 0.3%, P = .008, in group 1; and from 1.45 ± 0.5% to 3.8 ± 0.4%, P = .05, in group 2). At the end of the study, in patients from group 1, the glomerular filtration rate increased by 19% (from 94 ± 8 to 113 ± 13 mL/min, P = .039), and the urine flow increased by 39% (from 0.85 ± 0.14 to 1.12 ± 0.2 mL/min, P = .039), while no changes occurred in the renal function of patients from group 2. No changes were observed in the urinary excretion of prostaglandin (PG) E₂ or of 6-keto prostaglandin-1-α (6-K-PGF₁-α) nor in plasma renin activity (PRA) or the plasma concentration of aldosterone (PA) or antidiuretic hormone (ADH) in both groups. As far as undesirable effects of fish oils were considered, the mean arterial pressure (MAP) decreased in both groups (group 1: from 88.6 ± 2 to 85.3 ± 2 mm Hg, P = .015; group 2: from 88.2 ± 3 to 82.8 ± 3 mm Hg, P = .05), and bleeding time displayed a significant increase when patients were considered collectively (from 744 ± 89 to 872 ± 106 seconds, P = .0068). In conclusion, the administration of fish oil for 1 month was unable to improve renal function in cirrhotic patients with ascites and renal failure. The occurrence of undesirable effects, such as the reduction of arterial pressure and the prolongation of bleeding time, argues against the use of fish oils in these patients.