To the Editor: The exchange of letters in the February 21 issue of the Journal1 between correspondents and Henry Buchwald replying for the POSCH (Program on the Surgical Control of the Hyperlipidemias) Group regarding the group's report on partial ileal bypass in patients with hypercholesterolemia and coronary heart disease2 leaves several issues unresolved. The quantitative relation found between changes in serum levels of cholesterol and low-density lipoprotein (LDL) cholesterol and outcomes over a period of 9.7 years was disappointing and was not put in perspective. In the Lipid Research Clinics—Coronary Primary Prevention Trial (LRC-CPPT),3 which employed cholestyramine as the lipid-lowering. . .