Efficacy of n-3 fatty acid supplementation on rheumatoid arthritis’ disease activity indicators: a systematic review and meta-analysis of randomized placebo-controlled trials
Konstantinos Gkiouras, Maria G. Grammatikopoulou, Ioannis Myrogiannis, Theodora Papamitsou, Eirini I. Rigopoulou, Lazaros I. Sakkas, Dimitrios P. Bogdanos
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.