Effectiveness of fish oil in controlling inflammation in adult patients undergoing hemodialysis: A systematic review and meta-analysis

Objective: Hemodialysis patients with chronic kidney disease often exhibit inflammation characterized by elevated levels of C-reactive protein, Interleukin 6 and tumor necrosis factor-alpha, and they are shown to be associated with cardiovascular impairment and enhanced renal failure. This study aims to assess the impact of fish oil intake on inflammation indicators in adult hemodialysis patients. Methods: From the inception to December 2023, the datasets Cochrane Central, Google Scholar, Science Direct, Embase, and Pubmed were examined. Two authors independently searched, selected, and screened the literature. The pooled results are represented by weighted mean difference (WMD) with 95% confidence intervals. To investigate the causes of heterogeneity, subgroup analysis was done. Sensitivity analysis was then used to evaluate the validity of the combined findings. Results: Thirteen randomized control trials studies were included. The pooled results showed that fish oil supplementation caused a significant reduction of the C-reactive protein level (WMD, -2.92 mg/L; 95% Confidence interval, -5.23, to -0.61; p = 0.01; I2 = 99%), especially in patients with baseline C-reactive protein >= 5 mg/L (WMD, -4.39 mg/L; 95% Confidence interval, -5.93 to 2.85; p < 0.00001; I2 = 33%). Subgroup analyses showed that C-reactive protein baseline level (C-reactive protein <5 mg/L) was the main source of heterogeneity. Fish oil intake may not reduce the level of Interleukin 6 (WMD, -2.26; 95% Confidence interval: -19.61 to 15.09; p = 0.80; I2 = 93%), nor will it reduce the level of tumor necrosis factor-alpha (random model: WMD, -2.51; 95% Confidence interval: 6.08 to 1.06; p = 0.17; I2 = 98%). Conclusion: Hemodialysis patients, especially those with C-reactive protein > 5 mg/L, responded to fish oil supplementation to reduce their C-reactive protein level; however, Interleukin 6 and tumor necrosis factor-alpha levels did not appear to be affected.