Patients with rheumatoid arthritis (RA) are at increased risk of coronary artery disease (CAD) compared with individuals who suffer from CAD but not RA.
The findings of research published today in Arthritis Research & Therapy show that CAD is accelerated in RA patients, and patients with both RA and CAD are at an increased risk of death from heart disease. The authors of the study suggest that the high numbers of inflammatory T cells found in RA arthritis patients may cause the increased risk of CAD. Importantly, this increased risk results in a trend towards increased risk of death from cardiovascular disease for patients with rheumatoid arthritis.
The risk of cardiovascular diseases is higher in patients with RA. It is known that the processes leading to the chronic inflammation and autoimmune response seen in RA share features with those involved in atherosclerosis. Because of this, RA patients could be predisposed to CAD. Several studies have already shown an increased risk of atherosclerosis and heart attacks in patients with RA. Despite this knowledge, data is lacking on how high that risk is.
Kenneth Warrington and colleagues, from the Mayo Clinic in Minnesota, conducted a study of residents in Olmsted County, Minnesota, USA, with RA and new-onset CAD. These patients were compared to a control group of patients with newly diagnosed CAD. The two groups were then matched for age, sex and cardiovascular risk factors including diabetes, high blood pressure and smoking. For patients in both groups, the results of the first coronary angiogram – an x-ray image of blood vessels used to identify the exact location and severity of CAD – were examined.
The authors found that patients with RA have more advanced coronary atherosclerosis at the time of CAD diagnosis compared with patients without RA. This occurs independently of the presence or absence of other cardiovascular risk factors. This trend was mirrored in a trend towards increased frequency of cardiovascular death in RA patients. The risk of cardiovascular death in patients with RA and CAD was approximately twice that of the control group. According to the study's authors "the rheumatoid disease process itself likely contributes to accelerated coronary artery disease". Complications from atherosclerosis occur when an inflammatory lesion of T cells and other white blood cells accumulate in the inner layers of arteries. Elevated levels of a particular type of T cells, CD4+CD28- T cells, are seen in RA patients, where these cells play a central role in inflammation of the joints and disease progression.
This study demonstrates that, irrespective of other cardiovascular risk factors, patients with RA have significantly advanced multi-vessel CAD in comparison to patients with CAD but no RA. The increased risk of cardiovascular disease seen in RA patients is likely to arise from the underlying RA disease process, and specifically the raised levels of CD4+ and CD28- T cells that have previously been implicated in the pathogenesis of CAD.