Plasma n-3 fatty acids and clinical outcomes in recent-onset rheumatoid arthritis.
A randomised controlled trial (RCT) of high-dose v. low-dose fish oil in recent-onset rheumatoid arthritis (RA) demonstrated that the group allocated to high-dose fish oil had increased remission and decreased failure of disease-modifying anti-rheumatic drug (DMARD) therapy. This study examines the relationships between plasma phospholipid levels of the n-3 fatty acids in fish oil, EPA and DHA, and remission and DMARD use in recent-onset RA. EPA and DHA were measured in blood samples from both groups of the RCT. The data were analysed as a single cohort, and Cox proportional hazards models were used to examine relationships between plasma phospholipid (PL) EPA and DHA and various outcome measures. When analysed as a single cohort, plasma PL EPA was related to time to remission, with a one unit increase in EPA (1% total fatty acids) associated with a 12% increase in the probability of remission at any time during the study period (hazard ratio (HR)=1.12; 95% CI 1.02, 1.23; P=0.02). Adjustment for smoking, anti-cyclic citrullinated peptide antibodies and 'shared epitope' HLA-DR allele status did not change the HR. Plasma PL EPA, adjusted for the same variables, was negatively related to time to DMARD failure (HR=0.85; 95% CI 0.72, 0.99; P=0.047). The HR for DHA and time to remission or DMARD failure were similar in magnitude to those for EPA, but not statistically significant. Biomarkers of n-3 status, such as plasma PL EPA, have the potential to predict clinical outcomes relevant to standard drug treatment of RA patients.
1Rheumatology Unit,Royal Adelaide Hospital,Adelaide,SA 5000,Australia.
Susanna M
SM
Proudman
1Rheumatology Unit,Royal Adelaide Hospital,Adelaide,SA 5000,Australia.
Leslie G
LG
Cleland
1Rheumatology Unit,Royal Adelaide Hospital,Adelaide,SA 5000,Australia.
Robert G
RG
Metcalf
3Public Health (TRS),University of Adelaide,Adelaide,SA 5000,Australia.
Thomas R
TR
Sullivan
1Rheumatology Unit,Royal Adelaide Hospital,Adelaide,SA 5000,Australia.
Llewellyn D
LD
Spargo
1Rheumatology Unit,Royal Adelaide Hospital,Adelaide,SA 5000,Australia.
Michael J
MJ
James
D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000178:diet therapy* / Q000188:drug therapy / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003131:Combined Modality Therapy; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000032:analysis / Q000097:blood* / Q000627:therapeutic use; D004311:Double-Blind Method; D004351:Drug Resistance; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000032:analysis / Q000097:blood* / Q000627:therapeutic use; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000037:antagonists & inhibitors; D010743:Phospholipids / Q000097:blood* / Q000737:chemistry; D016016:Proportional Hazards Models; D012074:Remission Induction
D018501:Antirheumatic Agents; D001323:Autoantibodies; D015415:Biomarkers; D005395:Fish Oils; D010456:Peptides, Cyclic; D010743:Phospholipids; C487763:cyclic citrullinated peptide; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid
ACR American College of Rheumatology; Arthritis; DAS28 Disease Activity Score; DMARD disease-modifying anti-rheumatic drug; Docosahexaenoic acid; Eicosapentaenoic acid; Fish oil; HR hazard ratio; Nutritional immunology; PL phospholipid; RA rheumatoid arthritis; RCT randomised controlled trial