PARIS – Postprandial triglyceride levels helped assess cardiovascular risk in patients with normal glucose tolerance but provided no extra prognostic information in those with impaired glucose tolerance or diabetes in a prospective study of 514 consecutive patients with stable coronary artery disease.
In the Homburg Cream and Sugar Study participants who were undergoing coronary angiography ate a standardized dinner at 6 p.m., fasted overnight, and at 8 a.m. drank 250 ml of cream containing 75 g of fat. Three hours later those who were not receiving treatment for diabetes also drank 250 ml of water containing 75 g of glucose.
Investigators then measured fasting and postprandial triglyceride concentrations, followed by insulin concentrations and glucose tolerance. Follow-up 12 and 18 months later identified cardiovascular events.
Diabetes was present in 46% of patients, and only 25% had completely normal glucose tolerance. Patient characteristics were typical of those with coronary artery disease, Dr. Ulrich Laufs and his associates reported at the annual congress of the European Society of Cardiology.
For the cohort as a whole, postprandial triglyceride levels did not correlate with the primary outcome, a composite of cardiovascular deaths or hospitalizations for cardiovascular events. A weak correlation between fasting triglycerides and the primary outcome became non-significant in multivariate analysis.
Fasting triglyceride levels, and to an even greater extent postprandial triglyceride levels, were independent markers for the primary cardiovascular outcomes, said Dr. Laufs of Saarland University Hospital, Homburg, Germany. In patients with diabetes and impaired fasting glucose, however, absolute fasting and postprandial triglyceride levels were high but did not independently predict risk of cardiovascular death or hospitalization.
The highest tertile of triglyceride concentrations – levels above 150 mg/dL – in patients with normal glucose tolerance predicted a tripling in risk for the cardiovascular endpoints, compared with the middle and lowest tertiles. The highest tertile of postprandial triglyceride levels predicted a four-fold increased risk in patients with normal glucose tolerance. The study controlled for the effects of other risk factors, including other lipids, age, and sex.
These findings were "a little bit surprising," he said.
The study was designed to help address ongoing debate about whether triglyceride levels add to other measures of cardiovascular risk. "There is evidence from primary prevention studies and from mechanistic basic science studies that maybe the triglyceride-rich lipoproteins that are increased after a meal may be especially atherogenic," Dr. Laufs said.
Photo credit: Sherry Boschert/Elsevier Global Medical News
Dr. Ulrich Laufs presents his findings at the annual congress of the European Society of Cardiology.
Triglycerides are regulated not only by the time and type of meal but other factors as well. Importantly, glucose metabolism influences triglyceride kinetics, the study showed. Compared to patients with diabetes, those without diabetes had lower concentrations of fasting and absolute triglycerides and increased postprandial triglycerides. The relative increase, however, was similar between these two groups, he said.
"For the majority of patients, the primary consequence of this analysis is that we have to look very carefully at glucose metabolism," he said. "We may have to focus more on patients with normal glucose tolerance. If those patients have high fasting triglycerides, they have increased risk. It may be interesting in the future to look at whether these patients may benefit from intervention."
The study was limited by looking at only the first 5 hours after a meal, statin therapy in 95% of patients, the absence of genetic testing, and a predominantly Caucasian cohort, he said.
Dr. Laufs has been a speaker for nearly all pharmaceutical companies dealing with lipids.