Triglycerides and Cardiovascular Disease: The Experts Speak

While debate continues about whether hypertriglyceridemia independently predicts coronary artery disease, mean triglyceride levels in the U.S. are rising, along with rates of obesity and diabetes. In a new scientific statement, the American Heart Association (AHA) outlines the scope of the problem and offers treatment recommendations. Triglyceride levels directly influence high- and low-density lipoprotein metabolism, and hypertriglyceridemia can be mediated genetically or acquired (e.g., in patients with hypothyroidism, diabetes, or renal disease).

The authors propose a “practical algorithm” for initial screening with nonfasting triglyceride measurement. If levels are <200 mg/dL (corresponding to <150 mg/dL on a fasting sample), they suggest that patients continue with healthy diet and activity levels. At levels ≥200 mg/dL, fasting lipoprotein measurement is advised, and suggested targets are provided for weight loss and intake of dietary carbohydrates, sugars, and fats. Increased physical activity and intake of ω-3 fatty acids also are advocated for their profound effects on elevated triglyceride levels. At the highest triglyceride levels or in symptomatic patients, pharmacologic therapy can be useful (e.g., to lower risk for pancreatitis in patients with triglycerides >500 mg/dL). At all triglyceride levels, the AHA recommends avoiding consumption of trans fats, which raise triglyceride levels and atherogenic lipid particles. Finally, the guidelines set <100 mg/dL as an optimal triglyceride level.

This statement summarizes what we know about triglycerides and their relation to disease and provides a framework for treating the many patients with suboptimal triglyceride levels (see JW Cardiol Jul 13 2011 for additional commentary from Harlan Krumholz). Patients should be advised that lifestyle changes in diet, weight loss, and exercise are basic to treating most cases of hypertriglyceridemia, although tightening the definition of an optimal triglyceride level could inadvertently invite additional prescribing.

— Kirsten E. Fleischmann, MD, MPH

In this AHA-sponsored statement, the authors acknowledge that the evidence for triglycerides as an independent predictor of cardiovascular events (i.e., after adjustment for other lipid fractions) remains controversial. They also acknowledge the lack of convincing clinical-trial evidence to support triglyceride-lowering drug therapies, independent of LDL-cholesterol–lowering or statin therapy; indeed, no benefit was seen in the recent AIM-HIGH study. Hence, this statement is somewhat self-contradictory: If drugs are not indicated (except to lower risk for pancreatitis when triglycerides are extremely elevated), and if lifestyle modifications that happen to lower triglycerides are worthwhile regardless of triglyceride levels, why should we closely monitor triglyceride levels? I am unaware of evidence that patients who track their triglyceride levels are more motivated to exercise, lose weight, and eat a heart-healthy diet than are patients who receive similar counseling without following triglycerides. A move to more-intense focus on triglyceride levels, and to a more stringent definition of “optimal” triglycerides, thus seems unnecessary and misguided.

— Allan S. Brett, MD