 
Fish Oil Supplements Reduce Clotting for Dialysis Patients |
More than 400,000 Americans receive ongoing dialysis, at an annual cost of more than $6 billion. Dialysis patients often have artificial vascular grafts constructed to allow easy access to their blood. Unfortunately, more than 50 percent of all access grafts suffer thrombosis (clotting) of the grafting within two years of placement. Thrombosis is the most common reason for hospitalization in dialysis patients and costs the United States about $3 billion annually.
"This is a huge problem for dialysis patients who have vascular grafts," Schmitz said. "Once clotting occurs, it is likely to keep happening, leading to repeated hospitalization. Consumption of fish oil has long been discussed as a reason why certain populations, such as Greenland Eskimos, have such low rates of heart disease. We sought to evaluate the effect the fatty acids in fish oil might have on thrombosis. "
Half of the patients in the study (who had newly placed vascular grafts) took four grams of fish oil daily, while the placebo group received four grams of corn oil. The patients were followed for a full year, or until a clot developed. Of the patients assigned to the fish oil, 77 percent remained free of a clot after a year, compared to only 29 percent of the patients who received corn oil. Analysis of other variables, including age, gender, body weight, dialysis time and bleeding time, indicated that the beneficial effect occurred primarily as a consequence of fish oil administration.
"We were astonished by the results," Schmitz said. "For more than three-quarters of the study group to sustain a year of dialysis without clotting is remarkable. Though there have been previous studies involving fish oil, this study is unique because it showed such a dramatic difference between those who took fish oil and those who didn't."
Laboratory research has demonstrated that the fatty acids derived from the fish oil inhibit the growth of muscle cells. This prevents the narrowing in the draining veins of new grafts, which decreases the chances of access clotting. These unique biological properties found in fish oils decrease the onset of complications in dialysis patients.
"Fish oil capsules are extremely well-tolerated, with very little to no side effects," Schmitz said. "Some patients reported a bit of a fishy aftertaste. But that seems a minor concession if the fish oil supplements greatly reduce the chance of clotting of the vascular graft."
The fish oil capsules were provided by the National Marine Fisheries and Ocean Animal Institute, a division of the Department of Commerce. The oil is taken from marine mammals, such as whales and seals. "Fish oil capsules found in health food stores do not have as high of a concentration of fish oil as the capsules that were produced for us. Patients would have had to take about 12 commercially produced capsules daily, instead of the four they took during our study," Schmitz said. "These are people who are often already taking several medications a day, and to add another 12 to their regimen would not be ideal."
Schmitz is seeking funding for a multi-center study to further investigate fish oil's benefits. "This study could have a substantial impact on quality of life and morbidity issues for dialysis patients, as well as an economic impact by its potential for lowering incidents of hospitalization," Schmitz said. "If we find the same benefits in further testing, fish oil capsules just need to be formulated properly for widespread use."
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