Abstract 14449: Long-Term Colchicine for Cardiovascular and Limb Risk Reduction in Peripheral Artery Disease

Introduction: Evidence from randomized trials suggests colchicine may reduce major adverse cardiovascular events (MACE) in patients with coronary artery disease. Colchicine's effect in lower extremity peripheral artery disease (PAD) is not known.

Methods: To make inferences about the real-world effectiveness of colchicine in PAD, we emulated a pragmatic target trial, leveraging variable prescription durations when adding colchicine to urate lowering therapy in patients with gout and PAD. Eligible patients received care at a multicenter academic health system between July 2007 and December 2019. Electronic health records were linked to Medicare claims data. Patients received either colchicine indefinitely (long-term) or for 3 months (short-term) and the observational analog of the per-protocol effect was estimated. Inverse probability weighted marginal structural models were used to adjust for potential confounding, immortal-time, and collider-stratification biases. The primary outcome was a 2-year composite of major adverse limb events (MALE), MACE, and all-cause mortality.

Results: A total of 1,025 patients were enrolled; mean age was 77 years (SD 7), 32% were female, and 9% were non-white race. The risk of the primary composite outcome at 2 years was 31.2% (95% CI 26.9, 35.2) in the long-term colchicine group and 32.7% (29.6, 36.4) in the short-term group (Figure), with a risk difference of -1.6% (-6.3, 3.4) and risk ratio of 0.95 (0.82, 1.11). Beyond 2 years, risk estimates of secondary outcomes in each group diverged, but confidence intervals also widened (Figure).

Conclusions: In a real-world sample of high-risk patients with PAD and gout, estimates of the effect of colchicine provided no conclusive evidence that colchicine decreased the risk of adverse cardiovascular or limb events and death. The cardiovascular and limb benefits of colchicine in older comorbid populations with PAD and advanced systematic atherosclerosis remain uncertain.