Apolipoprotein B-containing lipoprotein subclasses as risk factors for cardiovascular disease in patients with rheumatoid arthritis

Arthritis Care & Research , 05/07/2012

Knowlton N et al. – Apolipoprotein C–III (ApoC–III) containing Apolipoprotein B (ApoB) lipoprotein subclasses were found to be significantly elevated in progressors than non–progressors. Many of these same lipoproteins were found to be associated with an increase in Coronary Artery Calcium (CAC) scores amongst progressors. These lipoproteins may be considered new risk factors for progression of atherosclerosis in Rheumatoid Arthritis (RA) patients.

Methods

  • Apolipoprotein and lipoproteins were measured on 152 RA patients by immunoturbidimetric procedures, electroimmunoassays, and immunoprecipitation.
  • Patients had a Coronary Artery Calcium (CAC) score performed at baseline and year three.
  • Differences in CAC scores between baseline and year three were calculated and dichotomized at ‘0’, where patients with a difference score greater than ‘0’ were denoted progressors, while the rest were denoted non–progressors.
  • Differences between means were tested with a two–sided independent Student's T test with Satterthwaite adjustment.
  • Proportion differences were tested with a Chi–Square test.
  • Multiple logistic regression was performed to assess the relationship between apolipoprotein and lipoprotein levels and the dichotomized CAC score.

Results

  • Progressors accounted for almost 60% of the cohort. Progressors had significantly higher levels of: Triglycerides (TG), VLDL–C, TC/HDL, TG/HDL, ApoB, LpA–II:B:C:D:E, LpB:C, ApoB/ApoA–I, ApoC–III, and ApoC–III–HP than non–progressors.
  • After adjusting for age, gender (M/F), statin use (Y/N), Hypertension (Y/N), significant risk factors of progressors were: TC, TG, VLDL–C, LDL–C, ApoB, LpB:C, ApoC–III, ApoB/ApoA–I.

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