Contribution of pasting hyperinsulinemia to prediction of atherosclerotic cardiovascular disease status in 293 hyperlipidemic patients

In a cross-sectional study of 293 nondiabetic patients (169 men and 124 wom en) referred for the diagnosis and treatment of hyperlipidemia, our specifi c aim was to determine whether fasting serum insulin independently contribu tes to the prediction of atherosclerotic cardiovascular disease (ASCVD) sta tus. Of the 169 men and 124 women, 65 (38%) and 44 (35%), respectively, had ASCVD with at least one of the following: unstable angina, myocardial infa rction (MI), angioplasty, coronary artery bypass graft (CABG), claudication . transient ischemic attack, or ischemic stroke. In addition, 42% and 38% h ad fasting hyperinsulinemia (greater than or equal to 20 mu U/mL). Fasting serum insulin of 20 mu U/mL or higher was very common in women (59% to 100% ) and men (67% to 88%) when hypertension, obesity, top-decile triglyceride (TG), and bottom-decile high-density lipoprotein cholesterol (HDLC) were co ncurrent in various combinations. ASCVD events (present or absent) were dep endent variables in a stepwise logistic regression model with explanatory v ariables including age, gender, race, hypertension, cigarette smoking, ASCV D in first-degree relatives at age 55 years or less, Quetelet Index, fastin g serum insulin, a gender x insulin interaction term, anticardiolipin antib odies (ACLAs) IgG and IgM, total cholesterol to HDLC ratio, TG, lipoprotein (a) [Lp(a)], and homocysteine. The risk odds ratio for ASCVD (109 events an d 184 nonevents) for subjects with top-decile insulin (v the bottom nine de ciles) was 3.71, with a 95% confidence interval (CI) of 1.62 to 8.9 (P = .0 02). For patients with MI and/or CABG and/or angioplasty ([MCA] 63 events a nd 184 nonevents), the risk odds ratio for top-decile insulin versus the re st was 5.07 (95% CI, 1.83 to 14.8, P = .002). For patients with MCA at age 55 or less, the gender x insulin interaction term was significant (P = .000 4): the risk odds ratio for men with top-decile insulin was 13.28 (95% CI, 3.82 to 51.65, P = .0001). Hyperinsulinemia is very common in nondiabetic h yperlipidemic women and men. Fasting serum insulin, a crude, simple, practi cal, and inexpensive measure, independently and uniformly improved the pred iction of ASCVD status beyond traditional risk factors and lipid variables in patients referred for treatment of hyperlipidemia. Copyright (C) 1999 by W.B. Saunders Company.