Association between small dense LDL and sub-clinical atherosclerosis in patients with psoriatic arthritis

Psoriatic arthritis (PsA) is an inflammatory rheumatic disorder occurring in patients with psoriasis. Several studies have shown an association between Psa and traditional atherosclerotic risk factors. We evaluated the relationship between small dense low-density lipoproteins particles (sd-LDL) a risk marker for atherosclerosis, sub-clinical atherosclerosis and PsA in a group of 50 patients with PsA and in 100 controls. Cholesterol, high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides, insulin, homeostasis model assessment (HOMA), Apo B, and sd-LDL have been measured. LDL particle separation was performed and seven LDL subfractions were obtained, LDL score (percentage of sd-LDL) and mean LDL particle size were calculated. PsA patients and control group differ significantly (p < 0.001) in triglycerides values (119.3 ± 52.0 vs 90.7 ± 40.7 mg/dL), Apo B (1.1 ± 0.2 vs 0.9 ± 0.1 g/L), insulin (8.9 ± 4.9 vs 5.8 ± 3.2 mU/L), HOMA (2.2 ± 1.7 vs 1.3 ± 0.8), BMI (27.7 ± 3.3 vs 25.8 ± 3.8). LDL score is significantly higher in PsA as compared to control (9.0 ± 10.7 vs 2.9 ± 4.7 mg/dL); and mean LDL size is significantly lower in PsA than control (268.1 ± 4.6 vs 271.2 ± 2.7 Å). These differences were confirmed when stratifying PsA patients for treatment and for disease activity. LDL score and LDL diameter significantly were correlated with the carotid IMT in patients with PsA. These findings show a novel relationship between LDL score and mean LDL size with PsA diagnosis and with sub-clinical atherosclerosis. Sd-LDL gives potentially useful information in the risk assessment for atherosclerotic disease in PsA patients.