Lack of association of serum lipoprotein (a) levels with type-2 diabetes mellitus in patients with angiographically defined coronary artery disease

Multiple studies have demonstrated that elevated serum lipoprotein (a) [Lp( a)] levels are independent predictors for coronary artery disease (CAD) in subjects without diabetes mellitus (DM). However, their contribution in pat ients with DM is controversial and still requires clarification. We determi ned serum Lp(a) levels in 355 consecutive Caucasian patients (271 men and 8 4 women) with angiographically documented CAD, and in 100 control subjects (58 men and 42 women) who were clinically free of cardiovascular disease. I n addition, the association of serum Lp(a) levels with type-2 DM in patient s with CAD was investigated after reassigning patients according to the dia gnosis of type-2 DM (61 men and 40 women with type-2 DM and 210 men and 44 women without). No gender differences in Lp(a) levels were observed between men and women (patients and control subjects). Patients with CAD had highe r Lp(a) levels than the control subjects (33 (14-74) vs. 13 (9-29) mg/dl, P <0.001). Elevated Lp(a) levels (defined as >90th percentile of controls) we re significantly more prevalent in men and women with CAD (35% and 28%, res pectively) than in control subjects (13% and 10%, respectively). Serum Lp(a ) levels correlated with LDL cholesterol (r=0.22, P<0.001) and apo B levels (r=0.18, P<0.03) in patients and control subjects. Stepwise discriminant a nalysis revealed that Lp(a) was an independent risk factor for the presence of CAD, independent of smoking, hypertension, type-2 DM, LDL and HDL chole sterol or apo Al and B levels. When patients were studied according to the spread of CAD (evaluated as the number of narrowed vessels), no differences in serum Lp(a) levels were observed, nor was then a higher prevalence of e levated Lp(a) levels. Finally, when patients were re-assigned according to the diagnosis of type-2 DM, no effect of apo B and LDL-C levels on Lp(a) wa s found (r=0.06, P=n.s. and 40.14, P=n.s., respectively) and serum Lp(a) le vels neither associated nor contributed to the extent of CAD. Our results s howed that serum Lp(a) levels are increased in patients with angiographical ly documented CAD, but there were no significant differences between diabet ic and non-diabetic patients, which indicates that elevated Lp(a) levels ar e specifically associated with CAD but not with type-2 DM. (C) 2000 Elsevie r Science Ireland Ltd. All rights reserved.