Effect of Low-dose ColchiciNe on the InciDence of Atrial Fibrillation in Open Heart Surgery Patients: END-AF Low Dose Trial

Background: Studies using 1 mg of colchicine to prevent postoperative atrial fibrillation (POAF) reported conflicting results. Moreover, colchicine was associated with significant gastrointestinal (GI) side effects. This study examined whether low-dose colchicine effectively prevents POAF and whether low-dose therapy is associated with lower rates of colchicine-induced GI side effects.

Methods: In this prospective, randomized, double-blind, placebo-controlled study, consecutive adult patients admitted for elective cardiac surgeries randomly received a 1-mg dose of colchicine (n = 81) or placebo (n = 71) orally 12 to 24 hours before surgery followed by a daily dose of 0.5 mg until hospital discharge. The primary efficacy endpoint was the development of at least one episode of POAF of ≥5 minutes. The primary safety endpoint was the development of adverse events, especially diarrhea.

Results: The in-hospital mortality rate was 3.9%. POAF occurred in 13 patients (16.1%) in the colchicine group and 13 patients (18.3%) in the placebo group (odds ratio 0.85 [95% Confidence Interval = 0.37-1.99]). Diarrhea occurred in two patients in each group and necessitated treatment discontinuation in one patient in each group.

Conclusion: Low-dose colchicine did not prevent POAF in patients undergoing cardiac surgery. These results should be interpreted cautiously because of the small sample size and early study termination.ClinicalTrials.gov Unique Identifier number: NCT03015831.

Keywords: Atrial fibrillation; arrhythmia; cardiac surgery; colchicine; gastrointestinal toxicity; randomized controlled trial.