Short‐Term, Weight‐Adjusted Colchicine to Prevent Post‐CABG Arrhythmias: A Randomized, Double‐Blind, Controlled Trial

BACKGROUND: Postoperative arrhythmias are common after coronary artery bypass graft (CABG) surgery and are linked to adverse outcomes. Colchicine, an anti-inflammatory agent, has shown inconsistent results in prior studies, possibly due to dosing and timing variations. OBJECTIVES: To evaluate the efficacy and safety of short-term, weight-adjusted colchicine initiated preoperatively for preventing postoperative arrhythmias after CABG. METHODS: In this randomized, double-blind, placebo-controlled trial, 172 adults scheduled for on-pump CABG received colchicine or placebo. The regimen included a preoperative loading dose (1 mg twice daily) followed by a weight-based maintenance dose (0.5 mg daily if 48 h) POAF, other arrhythmias, inflammatory markers (CRP, ESR), length of stay, and adverse events. RESULTS: Of 163 analyzed patients (81 colchicine, 82 placebo), POAF incidence was significantly lower in the colchicine group (17.3% vs. 46.3%; RR 0.37, 95% CI 0.21-0.66; p < 0.001), with an absolute risk reduction of 29.0% and number needed to treat (NNT) of 4. Colchicine reduced both early and late POAF (p < 0.001 and p = 0.002). No significant reduction was seen in other arrhythmias. Gastrointestinal events, primarily diarrhea, were more common with colchicine (25.9% vs. 8.5%, p = 0.003), but were manageable and without serious adverse events. CONCLUSION: Short-term perioperative weight-adjusted colchicine is effective and safe for preventing POAF after CABG, with a low NNT and manageable side effects, though it did not significantly affect other arrhythmias. TRIAL REGISTRATION: Iranian Registry of Clinical Trials, IRCT20200328046886N6.