Secondary findings on the use of fish oil supplements showed a decrease in the time to thrombosis, rate of thrombosis, how often surgical and radiologic interventions, along with improved cardiovascular outcomes as reported by the researchers. These findings were published in the May 2nd JAMA issue by Charmaine E. Lok, MD, MSc (and colleagues) with the Toronto General Hospital in the Department of Medicine located in Ontario Canada.
Today's options for vascular access for the purpose of dialysis are such methods as central venous catheter, synthetic arteriovenous grafts and arteriovenous fistula as per the researchers. The synthetic arteriovenous grafts now are only used about 21% of the time because of the high risk for thrombosis.
According to findings, even with multiple interventions the rate of thrombosis has not been reduced. The researchers found that omega-3 fatty acids from fish oils could prevent thrombosis and arteriovenous graft stenosis from developing, because of the vasodilatory, antiproliferative and antioxidant effects they offer.
Randomly 201 adults were given fish oil capsules or a placebo in the FISH study; they all suffered from stage-5 kidney disease. This started on the 7th day after the graft was performed and went on for 1 year. The patients that took the fish oil did have some improvement on the loss of patency on the graft, but it was not that significant over the group that took the placebo. The secondary results showed differences that are more significant though with the fish oil patients having a much lower rate of failure with the grafts compared to the placebo patients.
The fish oil group showed significantly higher results for a 12-month period free from loss of native patency compare to those in the placebo group. There was also significant improvement in the rate cardiovascular survival, along with systolic blood pressure being reduced in the fish oil group.
The authors of the report state, "Although the risk of the primary end point was not significantly lower among fish oil recipients, this should be considered in the context of the apparent consistent clinical benefits observed for the secondary outcomes."
Even with flaws in the design of the study, it still resulted in important data being uncovered. Bradley S. Dixon, MD at the College of Medicine at the University of Iowa, stated in an editorial that most secondary results for clinical trials are considered not as important, because they are thought of as exploratory or confirmatory in nature.
Dr. Dixon goes on to say that when there are high rates of the baseline event, further analysis performed on the rate and proportion could be useful. The secondary results could detect more minute ways that fish oil affects patency. He writes, "Although the study was ultimately underpowered for the primary outcome, the secondary outcomes measuring the rate of loss of graft patency are important and relevant and deserve the attention of physicians caring for patients receiving a new graft."
Fish Oil For Hemodialysis Patients
Kevan R. Polkinghorne, MB, ChB, PhD, another independent source, from Department of Medicine for Monash University states, "A more definitive study was needed," he told Medscape Medical News, "and this study provides much more evidence that fish oil does indeed reduce graft thrombosis and loss in hemodialysis patients."
He added, "Preventing graft thrombosis and graft loss is an important clinical goal and is beneficial to patients by reducing interruption to their dialysis treatment. The treatment itself appears to be safe and is freely available and thus is applicable to the majority of patients with arteriovenous grafts on hemodialysis."