Precision Anti-Inflammatory Therapy in Atherosclerosis: A Systematic Review and Meta-Analysis of Colchicine Timing and Clinical Outcomes in Patients with Atherosclerotic Cardiovascular Disease

Background: Despite optimal lipid-lowering and antithrombotic therapy, substantial residual cardiovascular risk persists in established atherosclerotic cardiovascular disease (ASCVD), partly driven by chronic vascular inflammation. Methods: Systematic review and meta-analysis of RCTs comparing colchicine to placebo or no treatment in adults with established ASCVD. Searches on March 21, 2026 (PubMed, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP). PROSPERO CRD420261346516. Primary outcome: 4-point MACE (CV death, MI, stroke, urgent revascularization). DerSimonian-Laird random-effects with HKSJ adjustment. Exploratory trial-level meta-regression: time-to-initiation (TTI) and cumulative dose as continuous moderators. Results: DL pooled HR for 4-point MACE: 0.68 (95% CI 0.51-0.89; p=0.0060). HKSJ-adjusted HR: 0.68 (95% CI 0.27-1.70; p=0.3018). Substantial heterogeneity (I2=81.4%; 95% prediction interval 0.29-1.57, crossing 1.0). Exploratory meta-regression: TTI (beta=-0.00187/day, p=0.003) and cumulative dose (beta=-0.00163/mg-day, p=0.0003; k=5, explicitly underpowered). Non-CV mortality: HR 1.07 (0.76-1.50; p=0.694). GI discontinuation: pooled RR 1.95 (1.09-3.48; p=0.024). GRADE certainty: Moderate (4-point MACE). Conclusions: Low-dose colchicine is associated with reduced 4-point MACE in ASCVD (DL HR 0.68; HKSJ HR 0.68). The substantial heterogeneity and wide prediction interval indicate that effect size varies substantially across clinical settings. The divergence between CLEAR SYNERGY (acute; HR 0.99) and sub-acute/chronic trials (HR 0.33-0.77) drives heterogeneity. Meta-regression suggests TTI and cumulative exposure may be key moderators but is underpowered. The non-CV mortality signal is not confirmed. This analysis informs precision anti-inflammatory prescribing in ASCVD.