title: The efficacy and dosage effect of corticosteroids for the prevention of atrial fibrillation after cardiac surgery: a systematic review.
abstract: BACKGROUND
  Atrial fibrillation (AF) complicates up to 60% of patients after cardiac surgery. Current prophylactic measures are inadequate. Corticosteroids down-regulate activation of the proinflammatory response (including C-reactive protein) after cardiopulmonary bypass and have been suggested to reduce the risk of postoperative AF.
  
  
  OBJECTIVE
  The goal of this meta-analysis was to determine (i) the efficacy of corticosteroids in preventing AF after cardiac surgery and (ii) the impact of different dosage regimens on this outcome.
  
  
  METHODS
  Sources included MEDLINE, Embase, the Cochrane Database of Systematic Reviews, and citation review of relevant primary and review articles.
  
  
  METHODS
  The study identified prospective, randomized, placebo-controlled clinical trials that evaluated the role of corticosteroids in preventing AF after cardiac surgery.
  
  
  METHODS
  Data were abstracted on study design, study size, type of cardiac surgery, corticosteroid dosage regimen, and the incidence of AF in the first 72 hours after surgery. The total cumulated dose of corticosteroid was classified as low dose (<200 mg/d), moderate dose (200-1000 mg/d), high dose (1001-10,000 mg/d), and very high dose (10,000 mg/d) of hydrocortisone equivalents. Meta-analytic techniques were used to analyze the data.
  
  
  RESULTS
  We identified 7 relevant studies that included 1046 patients. The corticosteroid regimen differed between all studies with the total cumulative dose varying from 160 to 21,000 mg of hydrocortisone equivalents; one study each used low-dose and very high-dose corticosteroid. Overall, the use of corticosteroids was associated with a significant reduction in the risk of postoperative AF, with an odds ratio of 0.42, 95% confidence interval of 0.27 to 0.68, and P = .0004. Significant heterogeneity was however noted between studies. When the low-dose and very high-dose studies were excluded, the treatment effect was highly significant (odds ratio, 0.32; 95% confidence interval, 0.21 to 0.50; P < .00001) with insignificant heterogeneity.
  
  
  CONCLUSIONS
  Moderate-dosage corticosteroid (hydrocortisone) should be considered for the prevention of AF in high-risk patients undergoing cardiac surgery. Although the optimal dose, dosing interval, and duration of therapy is unclear, a single dose given at induction may be adequate. The interaction between corticosteroids, beta-blockers, and amiodarone requires further study.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA. paul.marik@jefferson.edu
authors.forename: Paul E
authors.initials: PE
authors.lastname: Marik
authors.forename: Robert
authors.initials: R
authors.lastname: Fromm