Efficacy of n-3 fatty acid supplementation on rheumatoid arthritis’ disease activity indicators: a systematic review and meta-analysis of randomized placebo-controlled trials

Abstract

Theoretical evidence and previous studies suggest that oralnutrient supplementation (ONS) with n-3 fatty acids for rheumatoid arthritis (RA) has the potential to lower disease activity indicators and non-steroidal anti-inflammatory drug (NSAID) uptake. A systematic search was conducted on five databases/registries from inception until May 23, 2021 with the aim to identify randomized placebo-controlled trials comparing n-3 supplements to placebo on disease-specific outcomes. A total of 23 studies matched the criteria (PROSPERO: CRD42019137041). Pooled analyses revealed that n-3 ONS provided a small effect in reducing pain [standardized mean difference (SMD): −0.16, 95% confidence intervals (CI): −0.40 to 0.09], and tender (SMD: −0.20, 95% CI: −0.46 to 0.05) and swollen joint count (SMD: −0.10, 95% CI: −0.28 to 0.07). In sensitivity analyses, there was a small effect in the reduction of NSAIDs intake (SMD: −0.22, 95% CI: −0.90 to 0.46), and c-reactive protein was reduced only by 0.21 mg/dL (95% CI: −0.75 to 0.33). Similar findings were observed regarding other objective/subjective outcomes. The certainty of the evidence was mostly of “very low/low” quality. Overall, n-3 ONS in RA might have a limited clinical benefit. Previous findings suggesting a reduction in NSAID intake may have been biased from the inadequate blinding of interventions. © 2022 Taylor & Francis Group, LLC.