The efficacy of N-acetylcysteine in improving liver function: A systematic review and meta-analysis of controlled clinical trials

Background: N-acetylcysteine (NAC) could improve liver function through its antioxidant and anti-inflammatory activities. We conducted a systematic review and meta-analysis of randomized clinical trials to examine whether NAC administration could lead to changes in liver function. Methods: The search was done using appropriate keywords in PubMed-Medline, SCOPUS, Embase databases and Google Scholar up to July 2022. Random-effects model was employed to obtain the pooled estimate. Additional analyses including subgroup and sensitivity analyses were carried out. Results: Eight eligible studies were identified. The results indicated no significant effect of NAC on aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), [(SMD= -0.03 pg/ml; 95% CI: -0.53, 0.47; P = 0.917, I2 = 71.3%, P = 0.004), (SMD= -0.22 pg/ml; 95% CI: -0.63, 0.19; P = 0.288, I2 = 56.9%, P = 0.040), (SMD= -0.22 pg/ml; 95% CI: -0.67, 0.23; P = 0.343, I2 = 52.6%, P = 0.097), respectively], however, it significantly increased albumin (ALB) and decreased bilirubin levels [(SMD= 1.05 pg/ml; 95% CI: 0.41, 1.69; P < 0.001, I2 = 87.3%, P < 0.001) and (SMD= -0.34 pg/ml; 95% CI: -0.53, -0.14; P < 0.001, I2 = 0.0%, P = 0.447) respectively]. Conclusion: Although NAC might have favorable effect on ALB and bilirubin levels, larger trials assessing liver function as primary outcome are required.