Objective Clinical trials have evaluated the efficacy and safety of colchicine only in simple pericarditis, excluding cases of concomitant myocarditis. The aim of this paper is to evaluate the efficacy and safety of colchicine for the treatment of the first attack of acute pericarditis with concomitant myocardial involvement. Methods Double-centre retrospective cohort study analysing consecutive patients admitted for first attack of pericarditis with myocarditis and treated with or without colchicine. The primary efficacy end point was the time to the first recurrence. Propensity score matching was used to generate two groups of patients with similar baseline characteristics. Colchicine-associated side effects were analysed as safety end-point. Results A total of 175 patients (mean age 46.2±20.1 years, 25.1% females, 88.6% with idiopathic/viral aetiology) were included. Seventy-nine (45.1%) patients were treated with colchicine. After a median follow-up of 25.3 (IQR 8.3-45.6) months, 58 (33.1%) patients had recurrences. The propensity score generated two groups of 73 patients with similar baseline characteristics but the use of colchicine. Patients treated with colchicine had a lower incidence of recurrences (respectively, 19.2% vs 43.8%; p=0.001) and a longer event-free survival (p=0.005). In multivariable analysis, women (HR 1.97, 95% CI 1.04 to 3.73; p=0.037) and corticosteroid use (HR 2.27, 95% CI 1.15 to 4.47; p=0.018) were independent risk factors for recurrences. Colchicine-associated side effects were mild and occurred in 3 (1.7%) patients. Conclusion In patients with first attack of pericarditis associated with myocardial involvement, colchicine was safe and efficacious for the reduction of recurrences.
