Subjects with rheumatoid arthritis (RA) have increased cardiovascular risk and may show atherogenic forms of dyslipidemia. The present study investigated whether patients with early RA, beyond alterations in plasma lipids, also show lower LDL size and altered LDL subclass distribution.
We identified 25 subjects with RA (47+/-8 years, body mass index (BMI) 25+/-4kg/m(2)) by the American College of Rheumatology diagnostic criteria, with a disease durations <1 year and no prior treatment against it. In patients and 22 healthy subjects matched for age and BMI (controls) we measured plasma lipids and LDL size and subclasses by gradient gel electrophoresis.
As compared to controls RA patients had higher plasma triglycerides (1.8+/-0.5 vs. 1.0+/-0.5mmol/L, p<0.0001) and lower HDL-cholesterol concentrations (1.2+/-0.2 vs. 1.4+/-0.2mmol/L, p=0.0027), while total- and LDL-cholesterol concentrations were similar. LDL particle size was lower in RA patients than controls (264+/-7 vs. 281+/-9A, p<0.0001), due to less LDL-I (31+/-6 vs. 38+/-7%, p=0.0004) and LDL-IIA (14+/-3 vs. 16+/-3%, p=0.0182), and more LDL-IIIB (7+/-1 vs. 5+/-1%), -IVA (11+/-2 vs. 8+/-2%) and -IVB particles (12+/-2 vs. 9+/-2%,) (p<0.0001 for all). Further, about 1/3 of patients showed the complete "atherogenic-lipoprotein-phenotype" (e.g. the concomitant presence of high triglycerides, low HDL-cholesterol and elevated small, dense LDL).
Beyond plasma lipids, increased levels of small, dense LDL seems to be common in drug-naïve patients with early RA. Yet, whether these findings affect the atherogenic process and the clinical endpoints in these subjects remains to be determined by future prospective studies.