Determining the levels of two types of fat in the blood — called the atherogenic index of plasma — in patients with ankylosing spondylitis (AS) can help identify those at risk of developing life-threatening atherosclerotic heart disease, according to researchers.
Their study, “Atherogenic index of plasma: a useful marker for subclinical atherosclerosis in ankylosing spondylitis,” was recently published in the journal Clinical Rheumatology.
Ankylosing spondylitis is a chronic disease characterized by joint inflammation. It has also been linked to extra-articular manifestations (meaning they occur outside a joint) such as pain, fatigue, inflammation of the eye, and heart disease.
From 2-10% of patients are affected by cardiac problems, including conduction and rhythm defects, aortic valve insufficiency, and atherosclerotic cardiovascular disease — the building up of fat in the lining of arteries, making them narrower over time and constricting blood flow.
These AS-related complications, in particular atherosclerotic heart disease, are commonly associated wtih poor outcomes and an increased risk of mortality.
Researchers from Poland studied whether the atherogenic index of plasma (AIP) could be a useful predictor of heart disease in ankylosing spondylitis.
“Early detections of atherosclerotic cardiovascular disease in ankylosing spondylitis patients can lead to significant reductions to mortality and morbidity,” researchers wrote.
AIP is a measure based on the levels of two types of fat elements — triglycerides and high-density lipoproteins (HDL). AIP has been suggested as a predictive biomarker of atherosclerotic cardiovascular disease.
The study included 52 patients with diagnosed AS and 52 matched healthy volunteers. For each participant, researchers determined AIP, total cholesterol and HDL levels, and the thickness of the wall of the carotid artery (cIMT).
Patients were found to have a six times higher mean cIMT and 2.6 times higher mean AIP values than healthy volunteers. Also, patients had higher levels of triglycerides and C-reactive protein, both associated with heart disease.
The values of LDL cholesterol and HDL cholesterol, as well as other blood parameters commonly related to heart disease, were no different between the two groups.
cIMT and AIP values were found to be not only significantly correlated with each other, but also with disease duration and functional response of patients. In addition, AIP values were also found to be associated with disease activity as determined by the bath ankylosing spondylitis disease activity index (BASDAI).
According to researchers, these findings suggest that AIP can “be a novel marker in the early diagnosis of subclinical atherosclerosis” in patients with AS.
“It may also act as a more accurate marker than the classical atherogenic index in the identification of atherosclerotic cardiovascular disease risk,” they wrote.