Differential influence of LDL cholesterol and triglycerides on lipoprotein(a) concentrations in diabetic patients

OBJECTIVE- In evaluate the relationship between plasma lipid profiles and l ipoprotein(a) [Lp(a)] concentrations in diabetic patients, taking into acco unt the Lp(a) phenotype. RESEARCH DESIGN AND METHODS- We included 191 consecutive diabetic outpatien ts (69 type 1 and 122 type 2 diabetic patients) in a cross-sectional study. Serum Lp(a) was determined by enzyme-linked immunosorbent assay, and Lp(a) phenotypes were assessed by SDS-PAGE followed by immunoblotting. The stati stical methods included a stepwise multiple regression analysis using the L p(a) serum concentration as the dependent variable. The lipid profile consi sted of total cholesterol, HDL cholesterol, LDL cholesterol, corrected LDL cholesterol, triglycerides, and apolipoproteins A1 and B. RESULTS- In the multiple regression analysis, LDL cholesterol (positively) and triglycerides (negatively) were independently related to the Lp(a) conc entration, and they explained the 6.6 and 7.8% of the Lp(a) variation, repe ctively. After correcting LDL cholesterol, the two variables explained 3.8 and 6.4% of the Lp(a) variation, respectively. In addition, we observed tha t serum Lp(a) concentrations were significantly lower in patients with type IV hyperlipidemia (mean 1.0 mg/dl [range 0.5-17], n = 16) than in normolip idemic patients (6.5 mg/dl [0.5-33.5]. n = 117) and in type II hyperlipidem ic patients (IIa 15.5 mg/dl [3.5-75], n = 13; IIb 9 mg/dl [1-80], n = 45); P < 0.001 by analysis of variance. CONCLUSIONS- Lp(a) concentrations were directly correlated with LDL cholest erol and negatively correlated with triglyceride levels in diabetic patient s. Therefore, our results suggest that the treatment of diabetic dyslipemia may indirectly affect Lp(a) concentrations.