Abstract 1185: Changes in Small Dense LDL Particle Distribution with Addition of Niacin to a Statin Regimen. Do The Lipid Sub-Fractions Change to a Less Atherogenic Pattern?
Background/Objectives High levels of atherogenic lipid subparticles have been shown to increase risk for CAD. Niacin and statin combinations have been shown to reduce atherogenicity of lipid subfractions. However, we have observed that adding niacin to statin therapy did not always lower atherogenicity by decreasing the percent distribution of small dense LDL subfractions (IIIa+b). We analyzed our patients to seek predictors of this trend and find correlations with other lipid parameters.
Methods Lipid data from 136 patients on statin alone, and on additional 1500 mg/day of extended release or 3000mg/day of regular Niacin was analyzed. LDL subparticle percent was assessed by gradient gel electrophoresis. A 4% change in LDL IIIa+b subparticles was considered significant as per laboratory nomograms. We identified three groups of patients according to changes in LDL subparticles and analyzed conventional lipid parameters within each group (table⇓).
Results Population included patients (mean age 57±10.3 yrs, 75% men, 21% diabetics, 53% hypertensives, 32% CAD) seen in our lipid clinic. Follow-up occured at 18±8 weeks. Addition of niacin to a statin decreased LDL by mean 34±8 mg/dl (p<0.001), triglycerides (TG) by mean 34±12.4 mg/dl (p<0.001), and increased HDL by mean 7.8±2.3mg/dl (p<0.001) and HDL subfraction 2b by 5.5±2.2% (p<0.001). Lipoprotein(a) and CRP did not change significantly. LDL particle distribution trends are shown in the table⇓.
Conclusions Adding niacin to a statin regimen decreased atherogenicity of LDL subfractions in only a minority of patients (32%), despite universal improvements in other lipid parameters. The most prominent improvement in lipid values may actually be accompanied by worsened atherogenicity of LDL subfractions as evidenced by an increase in atherogenic LDL subfractions. Analysis of LDL subfractions may be an important component of lipid follow-up in patients with complex lipid disorders on combination statinniacin therapy.