title: Efficacy and safety of vitamin C for atrial fibrillation after cardiac surgery: A meta-analysis with trial sequential analysis of randomized controlled trials.
abstract: OBJECTIVE
  Antioxidant supplement is an option in preventing postoperative atrial fibrillation (AF) after cardiac surgery. However, the benefits and adverse effects of vitamin C have not been well assessed. We aimed to systematically evaluate the efficacy and safety of vitamin C in preventing postoperative AF in adult patients after cardiac surgery.
  
  
  METHODS
  PubMed, EMBASE, and the Cochrane library databases from inception to September 2016 were searched. Randomized controlled trials (RCTs) that evaluated the efficacy and safety of vitamin C in preventing postoperative AF in adult patients after cardiac surgery were identified. The primary outcome was the incidence of postoperative AF. Secondary outcomes included the length of intensive care unit (ICU) stay, length of hospital stay, and stroke events.
  
  
  RESULTS
  Eight RCTs incorporating 1060 patients were included. Compared with placebo group, vitamin C treatment was associated with a substantial reduction in postoperative AF (OR, 0.47; 95% CI, 0.36-0.62; evidence rank: moderate), with no significant heterogeneity (I244%; P = 0.09). Trial sequential analysis showed that the cumulative Z-curve crossed the trial sequential monitoring boundary for benefit, establishing sufficient and conclusive evidence. In addition, vitamin C administration was not associated with any length of stay, including in the ICU (evidence rank: low) and hospital (evidence rank: low), respectively.
  
  
  CONCLUSIONS
  Short-term treatment with vitamin C is safe, and may reduce the incidence of postoperative AF after cardiac surgery. Future studies as well as more high quality RCTs are still warranted to confirm the effects of different durations of vitamin C on cardiac surgery.
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
authors.forename: Linhui
authors.initials: L
authors.lastname: Yuan
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
authors.forename: Chang
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
authors.forename: Junying
authors.initials: J
authors.lastname: Cai
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Anaesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China. Electronic address: changhua_ma411@sina.com.
authors.forename: Changhua
authors.initials: C
authors.lastname: Ma
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000517:prevention & control*; D006348:Cardiac Surgical Procedures; D006801:Humans; D011182:Postoperative Care; D016032:Randomized Controlled Trials as Topic
chemical_list: D000975:Antioxidants; D001205:Ascorbic Acid
keywords: Meta-analysis; Postoperative atrial fibrillation; Trial sequential analysis; Vitamin C