January 15, 1997

Elevated Lipoprotein(a) and Premature Coronary Heart Disease-Reply

Author Affiliations

Tufts New England Medical Center Boston, Mass

JAMA. 1997;277(3):210. doi:10.1001/jama.1997.03540270036014

In Reply.  —Drs Maher and Brown emphasize several explanations for why we failed to detect a positive interaction between LDL cholesterol levels and elevated plasma Lp(a) levels, resulting in a heightened risk for incident premature CHD: low mean LDL cholesterol levels, low sensitivity of sinking pre-β lipoprotein band on electrophoresis, and the impact of LDL cholesterol-lowering therapeutic measures in the cohort. In fact, the mean LDL cholesterol levels are irrelevant—we sought evidence of interaction only in those individuals who had both elevated LDL cholesterol (ie, ≥4.1 mmol/L [160 mg/dL]) and elevated plasma Lp(a) levels. We agree that the sensitivity of sinking pre-β lipoprotein band is limited. However, our study was based on 129 incident CHD events vs only 16 incident CHD events in the study by Maher and colleagues.1 Accordingly, we must have had at least as much power to detect a positive interaction equivalent in magnitude to the one reported