Lipoprotein modification achieved by partial ileal bypass: Five-year results of the Program on the Surgical Control of the Hyperlipidemias

The Program on the Surgical Control of Hyperlipidemias (POSCH) is a multicentered, randomized, secondary intervention trial assessing the effect of lipoprotein modification achieved by partial ileal bypass (PIB) on overall mortality rates and the course of coronary heart disease. Of the 838 participants, 396 (196 control and 200 surgical patients) have complete 5-year lipoprotein results and are the basis of this report. After PIB, total cholesterol level decreased 24 ± 1.2% (mean ± SEM) and low-density lipoprotein cholesterol level fell 38 ± 1.5% in comparison with control subjects. High-density lipoprotein (HDL) cholesterol level was not changed by PIB; however, a significant decrease in HDL occurred over 5 years in the control group (41.7 ± 0.7 mg/dl versus 39.5 ± 0.6 mg/dl, p < 0.05). This led to consistently higher HDL levels in the surgical group in comparison with control subjects after PIB. Very low-density lipoprotein cholesterol and triglyceride levels were higher in the surgery group than in control subjects (24 ± 7.6% and 21 ± 5.4% at 5 years). Apolipoprotein B-100 was significantly lower, and apolipoprotein A-I and HDL-2 were significantly higher in the surgery group. These lipoprotein changes are greater than have been reported from any previous trial of dietary or pharmacologic intervention, including the Lipid Research Clinics-Coronary Primary Pevention Trial, which used cholestyramine. Based on available epidemiologic data, these changes predict a marked reduction in morbidity and mortality rates associated with coronary heart disease after PIB.