Fish Oil for IgA Nephropathy

Clinical Question

Will the administration of fish oil to patients with IgA nephropathy slow progression of renal failure?

Clinical Bottom Line

1. Fish oil appears to be significantly beneficial in retarding the progression to greater than a 50% increase in the serum creatinine compared to placebo controls in patients with IgA nephropathy.
2. There is no apparent effect on the degree of proteinuria in these patients.

The Evidence

Comments

1. This was a randomized, double-blinded study. Groups were basically similar at the start of the trial except for the degree of 24-hour proteinuria.
2. No obvious mention of an intention to treat analysis was made, however all patients were accounted for and analyzed in the groups to which they were randomized. For the 6% of treated patients and 33% of placebo patients who reached the primary endpoint, treatment codes were broken at that point and they were considered to have left the study. They were all followed up until the end of the study.
3. This was only a 2-year study. Given the significant variability in the rate of progression of this disease, long term follow-up would have been desirable.
4. As proteinuria is a more reliable predictor of progression to ESRD, the lack of significant effect on proteinuria raises some question about the long term efficacy of fish oil in retarding progression to ESRD.
5. Based on a NNT of only 3.7 and the inexpense of this agent, and given that IgA nephropathy is the most common glomerulopathy in the world with no other significant treatment modality, it is perhaps appropriate to recommend this therapy for all patients with IgA nephropathy.
6. No significant side-effects were noted.

APPRAISED BY: Shreenandh Krishnagopalan, MD

DATE: October 28, 1997

REVIEWED BY: Patrick J. Sousa, MD

Donadio JV, et al. A Controlled Trial Of Fish Oil In IgA Nephropathy. NEJM, 1994;331(18):1194-1199.