Exploring the Subclinical Atherosclerotic Load in Patients With Rheumatoid Arthritis: A Cross-Sectional Study

Background: Atherosclerosis is the major etiopathogenic factor that decides cardiovascular mortality and morbidity. While inflammation is the putative mechanism for atherosclerosis in various experimental studies, chronic inflammatory state (e.g. in rheumatoid arthritis [RA]) is often neglected as a contributing factor for the development of atherosclerosis. RA patients have two to four times more risk of fatal or non-fatal cardiovascular events, which is not explained by traditional risk factors alone. For example, low-density lipoprotein (LDL) cholesterol levels may not convey the true atherosclerotic risk in RA patients - “the lipid paradox”. Thus, for better risk stratification of future cardiovascular events in RA, the traditional parameters like diabetes, hypertension, and dyslipidemia may not suffice. Newer parameters like carotid intimal-medial thickness (CIMT), coronary calcification scores, and C-reactive protein (CRP) may be needed. This study determined subclinical atherosclerotic load in groups of RA and non-RA patients with comparable Framingham risk scores using CIMT values. Materials and methods: In this hospital-based cross-sectional study, the RA study group had 64 patients with RA (disease duration > 1 year) and 64 controls were patients with at least one traditional risk factor of cardiovascular disease (e.g., hypertension, cigarette smoking, dyslipidemia, and diabetes mellitus). They were all analyzed for CIMT. The aim was to compare if there was a difference in CIMT scores between groups of RA and non-RA patients, with comparable Framingham score cardiovascular risk categories. Results: CIMT was significantly higher in the study population compared to controls, indicating increased subclinical atherosclerotic load in the former. Mean CIMT was higher in all age groups in RA patients when compared to the control population (statistically significant in age groups 40-49 years 0.66 ± 0.07 mm vs 0.64 ± 0.06 mm, P < 0.026 and 50-59 years 0.8 ± 0.05 mm vs 0.76 ± 0.05 mm, P < 0.047). CIMT was significantly higher in the intermediate-risk groups (based on the Framingham risk score) in the RA study population when compared with the same risk categories of the control population. Atherogenic indices such as LDL/high-density lipoprotein (HDL) ratio, atherogenic index, and CIMT were significantly higher in the RA patients with more than five years of disease duration than those with a duration of fewer than five years. Conclusion: Subclinical atherosclerotic load is higher in RA versus controls. The mean CIMT was higher in all age groups in RA compared to the controls. CIMT was significantly higher in the intermediate-risk subgroup (by Framingham risk score) when compared between RA and controls. RA subgroup comparisons based on seropositivity/seronegativity, high/normal CRP, and disease activity (low, intermediate, and high) for CIMT were not found to have statistically significant differences. RA group had lower HDL cholesterol and comparable LDL cholesterol values compared to controls.