RA is associated with premature atherosclerosis. Here, we determined the associations of apolipoproteins and immunoglobulin M (IgM) antibodies against phosphorylcholine (anti-PC) with carotid artery atherosclerosis in a prospective cohort of patients with early RA.
In all 114 patients, age 50.6 (11.2) years, 68.4% women, with recent RA (<12 months after symptoms onset) were included and assessed at 0, 3, 12, 24 and 60 months after RA diagnosis. At the same time points, apolipoproteins were determined by immunoturbidimetry, and IgM anti-PC by ELISA. Carotid intima-media thickness (cIMT) (common carotid) and occurrence of plaques (common, internal and external carotids) were the principal study outcomes, which were examined with high-resolution B-mode ultrasonography after 5 years of RA disease. Mixed linear modelling and generalized estimating equations (GEEs) were used for longitudinal statistical analyses.
Multivariate regression analyses showed that age, male gender, smoking (ever) and history of cardiovascular disease (CVD), hypertension or diabetes mellitus, but no other baseline variables, had independent associations with cIMT (P < 0.05). Plaque detection was positively associated with age and smoking (ever). After adjustment, a longitudinal approach demonstrated an independent negative prediction of cIMT by apoA1 (P = 0.047), but a positive by apoB/apoA1 ratio (P = 0.030). Higher levels of pro-atherogenic apolipoproteins over time, apoB and apoB/apoA1 ratio, and low anti-PC tertile were independently associated with enhanced detection of bilateral carotid plaque (P = 0.002, 0.026 and 0.000, respectively). Both baseline and longitudinal levels of inflammatory/disease-related factors failed to show significant associations with the study outcomes.
Apolipoproteins and anti-PC may have independent roles in subclinical atherosclerosis in patients with RA.