Background Cardiovascular (CV) morbidity and mortality are increased in patients with rheumatoid arthritis (RA). A growing set of evidence shows the relationship between inflammation and CV risk. Insulin resistance (IR) is not only associated with the increased CV risk, but also involved in inflammatory process by adipocytokines. Carotid intima-media thickness (IMT), and carotid resistive index (RI) have been used as indictors for carotid atherosclerosis. While carotid IMT has been reported in patients with RA in many studies, the RI has not been studied yet.
Objectives We assessed the relationship between adipocytokines, insulin resistance and carotid atherosclerosis in RA via carotid IMT, plaque and RI to examine the hypothesis that adipocytokines affect insulin resistance and atherosclerosis.
Methods Common carotid IMT, common carotid RI, and carotid plaque were measured by high-resolution ultrasonography in 192 patients with RA. Patients who have overt diabetes were excluded. Insulin resistance was assayed by homeostasis model assessment for insulin resistance (HOMA-IR). Serum adipocytokine (adiponectin, leptin, resistin, TNF-α, IL-6) concentrations were determined.
Results Common carotid RI was independently associated with common carotid IMT after adjusting sex, conventional cardiovascular and metabolic risk factors (p=0.031); smoking, systolic blood pressure (SBP), waist circumference, glucose, triglycerides, HDL and LDL cholesterol. RI was also significantly associated with carotid plaque number (p=0.015) and estimated total plaque volume (p=0.033) after adjustment. Increased leptin:adiponectin ratio (p=0.021) was significantly related with higher HOMA-IR even after adjusting age, sex, and conventional risk. Resistin, TNF-α, IL-6, showed no significant association with HOMA-IR. Age, male sex, smoking, SBP, waist circumference, triglycerides, LDL cholesterol, and HOMA-IR were associated with increased carotid IMT by linear regression analysis. HOMA-IR was not associated with IMT after adjustment, nor with carotid plaque number, nor with plaque volume. Age, waist circumference, HOMA-IR and leptin:adiponectin ratio were related with increased carotid RI. Even after adjusting age, sex, conventional risk, and HOMA-IR, leptin:adiponectin ratio was the independent predictor for carotid RI (p=0.018).
Conclusions Common carotid RI was significantly associated with common carotid IMT, plaque number, and plaque volume. Leptin:adiponectin ratio was independently related with HOMA-IR and carotid RI. Leptin and adpiponectin might be involved in the pathogenesis of accelerated atherogenetic process in RA.
Gremese E, Ferraccioli G. The metabolic syndrome: The crossroads between rheumatoid arthritis and cardiovascular risk. Autoimmun Rev 2011;10:582-9.
Vicenzini E, Ricciardi MC, Puccinelli F, Altieri M, Vanacore N, Di Piero V, Lenzi GL. Common carotid artery intima-media thickness determinants in a population study. J Ultrasound Med 2007;26:427-432.
Disclosure of Interest None Declared