The LoDoCo (Low-Dose Colchicine in Coronary Artery Disease) trials represent a significant advancement in understanding and managing cardiovascular health. These studies investigated a novel approach to reducing the risk of heart-related events in individuals already affected by heart disease. The findings have reshaped perspectives on inflammation’s role in cardiovascular conditions and underscore the potential for existing medications to offer new benefits in preventing serious complications.
Background and Purpose of the LoDoCo Trials
A persistent challenge in cardiovascular care involves ongoing inflammatory processes that contribute to heart disease progression, even when traditional risk factors are managed. This “residual inflammatory risk” can lead to further cardiovascular events despite optimal cholesterol-lowering and anti-clotting therapies. Addressing this unmet need became the central rationale for the LoDoCo trials, which sought to explore alternative therapeutic strategies.
The drug investigated was colchicine, a medication used for conditions like gout and familial Mediterranean fever. Colchicine possesses anti-inflammatory properties by interfering with microtubules, cellular structures involved in immune cell movement and the release of inflammatory molecules. By disrupting these processes, colchicine reduces inflammation, a mechanism hypothesized to mitigate cardiovascular and atherosclerotic risk. The “LoDoCo trials” refer to a series of studies, including LoDoCo2, collectively aiming to determine if low-dose colchicine could safely prevent recurrent cardiovascular events.
Major Findings from the LoDoCo Trials
The initial LoDoCo trial, published in 2013, demonstrated that low-dose colchicine reduced the risk of a composite primary endpoint by 55% compared to placebo in patients with stable coronary artery disease. Gastrointestinal side effects were more common in the colchicine group but were generally mild.
Building on these results, the larger LoDoCo2 trial enrolled over 5,500 patients with chronic coronary disease, randomizing them to receive 0.5 mg of colchicine daily or a placebo. After a median follow-up of 28.6 months, the primary composite endpoint, which included cardiovascular death, myocardial infarction, ischemic stroke, or ischemia-driven coronary revascularization, occurred in 6.8% of the colchicine group compared to 9.6% in the placebo group. This represented a 31% reduction in risk for the primary composite endpoint with colchicine.
The beneficial effects extended to several individual secondary endpoints, including a 30% reduction in myocardial infarction and a 25% reduction in ischemia-driven coronary revascularization. A composite of cardiovascular death, myocardial infarction, or ischemic stroke was reduced by 28%. While the trial showed no statistically significant difference in all-cause mortality or cardiovascular death alone, a signal for higher non-cardiovascular mortality was observed in the colchicine group, though the reasons for this were not clear.
Impact on Patient Care
The LoDoCo trials’ evidence has begun to reshape treatment strategies for individuals with cardiovascular disease. These findings have influenced clinical guidelines, with organizations like the European Society of Cardiology endorsing low-dose colchicine for patients across the spectrum of coronary artery disease. In June 2023, low-dose colchicine, specifically the 0.5 mg formulation, received FDA approval in the United States to reduce the risk of major cardiovascular events, including myocardial infarction, stroke, coronary revascularization, and cardiovascular death.
Low-dose colchicine therapy is considered for adults with established atherosclerotic cardiovascular disease or those with multiple risk factors. The recommended dosage is 0.5 mg orally once daily. It is typically added to existing standard therapies, such as statins and antiplatelet medications, which most LoDoCo trial participants were already receiving.
Practical considerations for therapy include potential side effects, such as gastrointestinal issues like diarrhea, vomiting, or stomach cramps, and muscle pain. While generally mild, these symptoms can lead to discontinuation in some patients. Colchicine is contraindicated in patients with severe renal or hepatic impairment, pre-existing blood disorders, or those taking strong inhibitors of certain liver enzymes or transport proteins, due to the risk of increased colchicine levels and toxicity. Despite these considerations, colchicine is generally affordable, representing a cost-effective option for cardiovascular risk reduction.