Association of HDL Cholesterol Efflux Capacity with Incident Coronary Heart Disease Events

This nested case-control study within the EPIC-Norfolk cohort enrolled 3,494 participants (1,745 incident CHD cases, 1,749 controls matched for age, sex, and enrollment date) to test whether HDL cholesterol efflux capacity — a functional measure of HDL’s ability to accept cholesterol from macrophages — predicted incident coronary heart disease independently of HDL-C concentration.

Higher cholesterol efflux capacity was significantly and independently inversely associated with incident CHD, with each standard deviation increase associated with approximately 20% lower CHD risk after adjustment for HDL-C and traditional risk factors. Critically, the association was independent of HDL-C level — meaning that measuring efflux capacity provides risk information beyond what HDL-C concentration alone captures.

The finding is mechanistically coherent. The failure of HDL-raising therapies (niacin, CETP inhibitors) to reduce cardiovascular events — despite raising HDL-C — suggested that HDL-C concentration is a poor proxy for the biological function that protects against atherosclerosis. Cholesterol efflux — the first step in reverse cholesterol transport — is the specific mechanistic function proposed to be cardioprotective. This study is among the first large prospective studies to confirm that efflux capacity predicts CHD independently.

The practical limitation is that cholesterol efflux assays are research-grade and not available in clinical practice. Their development into routine clinical tests could eventually enable more informative HDL assessment than HDL-C alone.

We rate the evidence moderate. A well-designed prospective case-control study establishing cholesterol efflux capacity as an independent CHD predictor — important evidence reframing how HDL function should be measured rather than simply quantified.