Objective: To evaluate the efficacy of the essential omega-6 fatty acid Gammalinolenic acid (GLA) on fatigue associated with primary Sjögren's syndrome.
Methods: 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.
Results: 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.
Conclusion: According to our study results GLA (Evening Primrose oil) treatment for fatigue in primary Sjögren's syndrome is ineffective.