The Effects of N-acetylcysteine on Inflammatory Markers and Homocysteine: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Recently a number of trials investigated the effect of N-acetylcysteine (NAC) administration on inflammatory markers and homocysteine (Hcy). However, their findings are controversial. The aim of this paper is to present a meta-analysis and give a review of all randomized controlled trials (RCTs) in order to determine the effects of NAC on inflammatory markers and Hcy.

An electronic search was conducted using PubMed, Scopus, Cochrane Library, Google scholar and Web of Science databases from inception until April 2019. A study quality assessment was performed using the Jadad scale and heterogeneity between studies was statistically computed using Cochrane’s Q test and I-square (I2). Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size.

Out of 1115 potential citations, 10 studies (reported 13 effect sizes for different parameters) met the inclusion criteria and were eligible for this meta-analysis. NAC supplementation resulted in a significant reduction in Hcy levels (WMD: -2.05; 95% CI: -3.73, -0.37). NAC administration did not affect C-reactive protein (CRP) levels (WMD: 0.06; 95% CI: -0.21, 0.34), tumor necrosis factor-α (TNF-α) levels (WMD: 0.07; 95% CI: -0.27, 0.40), and interleukin 6 (IL-6) (WMD: -0.23; 95% CI: -1.23, 0.77).

It could be concluded that this meta-analysis of RCTs demonstrated that NAC administration to various patients significantly improved circulating Hcy, but did not affect CRP IL-6 and TNF-α levels.