Background Acute coronary syndrome (ACS) is a global leading cause of morbidity, with residual inflammation contributing to recurrent events. Colchicine has been proposed as an adjunct therapy, but its efficacy remains uncertain. Methods We performed a systematic review and meta-analysis. PubMed, Embase and Cochrane databases were searched for randomised controlled trials (RCTs) data comparing colchicine versus placebo in ACS. Risk ratio (RR) and mean difference with 95% CIs were computed for binary and continuous outcomes, respectively. Primary outcomes were adverse cardiovascular events (ACEs), mortality and safety. Random-effects models were used for pooled estimates. Results Seventeen RCTs comprising 14 794 patients were included, of whom 7390 (50%) were randomised to colchicine. The mean patient age across the studies ranged from 54 to 63 years, in a follow-up period ranging from 5 days to 12 months. Colchicine reduced the incidence of recurrent ACS (RR 0.41, 95% CI 0.19 to 0.92; p=0.03; I²=55%) and unstable angina (RR 0.27, 95% CI 0.11 to 0.63; p<0.01; I²=0%). No meaningful differences were observed in all-cause mortality (RR 0.95, 95% CI 0.79 to 1.14; I²=12%), cardiovascular death (RR 1.03, 95% CI 0.82 to 1.30; I²=0%) or ACE (RR 0.77, 95% CI 0.59 to 1.01; p=0.05; I²=58%). Subgroup analyses suggested a dose-dependent effect, with 0.5 mg/day potentially reducing ACE (RR 0.63, 95% CI 0.45 to 0.88; I²=41%), but higher doses increasing gastrointestinal symptoms. Conclusion Low-dose colchicine may reduce recurrent ischaemic events in ACS, but evidence remains uncertain due to heterogeneity and limited long-term data. Safety and efficacy in women and optimal dosing require further investigation. Trial registration number CRD42024627348.

Despite advances in device therapy and the emergence of novel treatments, beta-blockers (BBs) remain a commonly prescribed medication in heart failure (HF). However, HF with preserved ejection fraction (HFpEF) is underdiagnosed and undertreated, and the specific role of BB therapy in this population remains controversial. A comprehensive search was conducted on PubMed, Embase, and Cochrane databases to identify studies evaluating the impact of BB use on clinical outcomes in patients with HFpEF. Data were pooled using a random-effects model to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), and heterogeneity was assessed using I² statistics. We identified 13 observational studies comprising 442,543 patients, of whom 48.3% were women, with a mean age of 76.0 ± 8.3 years. In pooled analyses, BB use was associated with a lower risk of all-cause mortality (HR 0.81, 95% CI 0.73-0.90, p < 0.001). BB therapy was also associated with lower risks of cardiovascular death (HR 0.76, 95% CI 0.64-0.90, p < 0.01), HF hospitalization (HR 0.88, 95% CI 0.78-1.00, p = 0.05), and the composite outcome of death or HF hospitalization (HR 0.89, 95% CI 0.82-0.98, p = 0.02). In conclusion, in this observational meta-analysis, BB use was associated with lower mortality risk in HFpEF, whereas associations with hospitalization outcomes were heterogeneous. These findings should be interpreted as hypothesis-generating and warrant confirmation in adequately powered randomized trials.