WASHINGTON – High-risk patients managed to a target LDL particle number rather than to an LDL cholesterol goal had 25% fewer cardiovascular events over 3 years of follow-up.
"These new data add to the growing body of evidence suggesting that [nuclear magnetic resonance] measurement of LDL particle number, when used in conjunction with other lipid measurements, is a valuable cardiovascular risk management tool," Dr. Terry A. Jacobson declared at the annual meeting of the American College of Cardiology.
LDL cholesterol level and LDL particle number are often discordant, particularly in patients with diabetes, metabolic syndrome, or hypertriglyceridemia. Data from several major epidemiologic studies, including the Framingham Offspring Study (J. Clin. Lipidol. 2007;1:583-92), have shown that LDL particle number better predicts cardiovascular events than LDL cholesterol level.
Bruce Jancin/Frontline Medical News
Dr. Terry A. Jacobson
Until now, however, what has been missing is real-world evidence that treating to a target LDL particle number leads to better clinical outcomes than treating to a target LDL cholesterol number, explained Dr. Jacobson, professor of medicine at Emory University and director of the Office of Health Promotion and Disease Prevention at Grady Health Systems, both in Atlanta.
He presented a retrospective, nonrandomized analysis of 705 patients with coronary heart disease or a CHD equivalent who were placed on lipid-lowering therapy aimed at lowering their LDL particle number to less than 1,000 nmol/L and were then followed for 3 years. They were matched based upon demographics and comorbidities to an equal number of high-risk patients whose lipid-lowering regimen brought them below a target LDL cholesterol of 100 mg/dL.
During 3 years of follow-up, one or more CHD events or strokes – the composite primary end point – occurred in 14.6% of the group targeted to an LDL particle number below 1,000 nmol/L, compared with 19% of those whose goal was an LDL cholesterol level below 100 mg/dL, for a 25% relative risk reduction.
In a separate cohort of 4,188 matched high-risk patients followed for 12 months, the composite end point occurred in 6.3% of the group with an LDL particle number target, compared with 8.1% with an LDL cholesterol target of less than 100 mg/dL, for a 24% relative risk reduction, he added.
All participants in this study were selected from the HealthCore Integrated Research Database, which is associated with WellPoint, a large commercial health plan. These were high-risk patients: 60% had cardiovascular disease at baseline, and 57% had diabetes.
Attaining an LDL particle number of less than 1,000 nmol/L entailed a more aggressive lipid-lowering strategy than the one employed to drive LDL cholesterol below 100 mg/dL. Patients managed to the LDL particle number target were more likely to receive higher-potency statins at baseline. As a result, their mean LDL cholesterol was lower: 73 mg/dL in the group followed for 3 years, compared with 79 mg/dL in patients with an LDL cholesterol target of less than 100 mg/dL.
LDL particle number was measured via nuclear magnetic resonance technology using the NMR LipoProfile test, the sole Food and Drug Administration-approved blood test for this purpose.
The proprietary test is marketed by LipoScience, which funded this study. Dr. Jacobson is a consultant to the company as well as to Amarin, AstraZeneca, HealthCore, Merck, and Regeneron/Sanofi.