To evaluate the efficacy of the essential omega-6 fatty acid Gammalinolenic acid (GLA) on fatigue associated with primary Sjögren's syndrome.
Ninety patients with primary Sjögren's syndrome (with or without signs of autoimmunity) entered a 6-month double blind placebo-controlled randomised trial with high dose GLA (extracted from Evening Primrose Oil) or corn oil. The primary outcome parameter was fatigue; secondary endpoints were eye dryness, mouth dryness, muscle and joint pain.
No statistically significant improvement was found in fatigue assessed by Visual Analogue Scale (VAS) or in the time needed for sleeping/resting during a 24-hour period. No differences were found between the treatment and placebo group. The same applies to the secondary endpoints: no differences in VAS for eye and mouth dryness or pain, no significant changes in Schirmer-1-test, van Bijsterveld score, unstimulated whole sialometry (UWS), or use of artificial tears or analgesics. Only mild side effects were observed.
According to our study results GLA (Evening Primrose oil) treatment for fatigue in primary Sjögren's syndrome is ineffective.