The effect of N-acetylcysteine on the incidence of contrast-induced kidney injury: a systematic review and trial sequential analysis

Background There have been a myriad of studies investigating the effectiveness of N-acetylcysteine (NAC) in the prevention of contrast induced nephropathy (CIN) in patients undergoing coronary angiography (CAG) with or without percutaneous coronary intervention (PCI). However the consensus is still out about the effectiveness of NAC pre-treatment due to vastly mixed results amongst the literature. Objectives The aim of this study was to conduct a meta-analysis and trial sequential analysis to determine the effects of pre-operative NAC in lowering the incidence of CIN in patients undergoing CAG and/or PCI. Methods A systematic literature search was performed to include all randomized controlled trials (RCTs) comparing NAC versus control as pretreatment for CAG and/or PCI. A traditional meta-analysis and several subgroup analyses were conducted using traditional meta-analysis with relative risk (RR), trial sequential analysis, and meta-regression analysis. Results 43 RCTs met our inclusion criteria giving a total of 3277 patients in both control and treatment arms. There was a significant reduction in the risk of CIN in the NAC treated group compared to control (OR 0.666; 95% CI, 0.532-0.834; I2 = 40.11%; p = 0.004). Trial sequential analysis, using a relative risk reduction threshold of 15%, indicates that the evidence is firm. Conclusions The results of the present paper support the use of NAC in the prevention of CIN in patients undergoing CAG ± PCI. Future studies should focus on the benefits of NAC amongst subgroups of high-risk patients.