The quality of evidence is downgraded by potential reporting bias.
A systematic review 1 including 10 RCTs was abstracted in DARE. A statistically significant improvement was found at 3 months in tender joint count (rate difference = -2.9, 95% CI -3.8 to -2.1) and duration of morning stiffness. The conclusions were supported by reanalysis of the complete primary data set and were relatively invariant to statistical modelling techniques.
Clinical benefits of the n-3 fatty acids were not apparent until they were consumed for > or = 12 wk, a minimum daily dose of 3 g eicosapentaenoic and docosahexaenoic acids is necessary to derive the expected benefits. Because the methods used to determine whether patients taking n-3 supplements can discontinue taking there agents are variable, confirmatory and definitive studies needed to settle this issue 2.
An RCT included 140 patients with early rheumatoid arthritis (disease duration less than 12 months) without prior disease-modifying antirheumatic drugs (DMARDs). All patients received triple DMARD therapy with methotrexate, sulfasalazine, and hydroxychloroquine, with doses adjusted according to algorithm taking disease activity and toxicity into account. NSAIDs and oral cortcosteroids were actively discouraged and parenterally administered corticosteroids were permitted as clinically indicated. The study compared fish oil concentrate providing 5.5 g/day omega-3 fatty acids (35% eicosapentaenoic acid [EPA] and 25% docosahexaenoic acid [DHA]) with control group (sunola oil+capelin oil providing 400 mg/day EPA+DHA; masking smell and taste). At 1 year, 10.5% of subjects in the fish oil group and 32.1% of subjects in the control group had commenced leflunomide,an indicator of failure of triple DMARD therapy. Time-to-event analysis for failure rate of triple DMARD therapy in the fish oil group compared to control group: unadjusted HR 0.28, 95% CI 0.12 to 0.63 and adjusted HR 0.24, 95% CI 0.10 to 0.54 (adjustment for smoking history, shared epitope and baseline anti-cyclic citrullinated peptide). The time to first ACR remission in the first year of treatmentwas significantly less in the fish oil group compared with thecontrol group. No significant differences were observed in mean methotrexate dose, activities of daily living scores or adverse events.
Comment: An effective antiinflammatorydose of omega-3 fatty acids estimated in previous studies is at least2.7 g/day EPA+DHA.
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