Hyperinsulinemia, lipoprotein (a), and Chlamydia pneumoniae antibodies - Are they risk factors or serologic predictors for progression of coronary artery disease?

The authors studied 134 patients with unstable angina pectoris symptoms and 32 subjects without coronary artery disease (CAD) for the presence of clas sical risk factors such as hypercholesterolemia, smoking, and family histor y of CAD. In addition they analyzed plasma insulin levels, lipoprotein (a) (Lp[a]) levels, and antibody titers against Chlamydia pneumoniae. All patie nts had a heart catheterization. Patients with diabetes mellitus were exclu ded from the study. Fasting insulin, low-density lipoprotein (LDL) choleste rol and Chlamydia pneumoniae immunoglobulin G (IgG) and IgA antibody titers did not show any difference in CAD from healthy control subjects, whereas Lp(a) was increased and high-density lipoprotein (HDL) decreased in CAD pat ients. These data indicate that lipoprotein (a), low HDL cholesterol, and s moking, but neither hyperinsulinemia nor elevated Chlamydia pneumoniae tite rs, are risk factors or predictors for CAD.