Fasting Triglycerides and Prognosis After Acute Coronary Syndrome | Journal Scan
Study Questions:
What is the relationship of fasting triglyceride levels to outcomes after acute coronary syndrome (ACS) in patients treated with statins?
Methods:
This was a post hoc analysis of data from the dal-OUTCOMES trial and the atorvastatin arm of the MIRACL trial. The dal-OUTCOMES trial was a randomized, double-blind comparison of the cholesteryl ester transfer protein inhibitor dalcetrapib with placebo in 15,871 patients with recent ACS; 97% of patients were treated with a statin at randomization, with a median low-density lipoprotein cholesterol (LDL-C) of 73 mg/dl. The MIRACL trial was a randomized, double-blind comparison of atorvastatin 80 mg daily with placebo in 3,086 patients with ACS. This post hoc analysis includes data from 1,051 patients assigned to treatment with atorvastatin 80 mg, who had a fasting lipid profile determined at randomization. Primary outcomes were coronary heart disease death, nonfatal myocardial infarction, stroke, and unstable angina. Hazard ratios were determined for a 10 mg/dl increment in triglycerides at baseline, both in univariate relationships and in adjusted analyses.
Results:
In the dal-OUTCOMES trial, the median triglyceride concentration at randomization was 115 mg/dl. In the MIRACL trial, lipid levels were obtained before statin treatment, and median triglyceride concentration was higher, at 160 mg/dl. In the dal-OUTCOMES trial, relative to the lowest quintile (≤80 mg/dl), long-term risk for a primary endpoint event (during a median 31-month follow-up period) in the highest quintile of triglycerides (>175 mg/dl) was 1.61 (95% confidence interval [CI], 1.34-1.94). In the atorvastatin group of the MIRACL trial, relative to the lowest tertile (≤135 mg/dl), adjusted risk for a primary endpoint event (within 16 weeks following ACS) in the highest tertile of triglycerides (>195 mg/dl) was 1.50 (95% CI, 1.05-2.15). The relationship of triglycerides to risk was independent of LDL-C in both studies.
Conclusions:
Among patients receiving statin therapy following ACS, fasting triglyceride levels are independently associated with short- and long-term risk for adverse cardiovascular events.
Perspective:
This is an important study that provides insight from a large cohort of patients with ACS, and demonstrates that elevated triglycerides are associated with a worse prognosis, independent of statin therapy. Though the distribution of triglyceride levels differed in the dal-OUTCOMES and MIRACL studies, the authors correctly point out that ‘both sets of observations are important because a substantial fraction of patients who present with ACS are statin-naïve.’ Certainly, the results of this analysis would lend support to a strategy of lowering non–high-density lipoprotein cholesterol to minimize short- and long-term risks following ACS. Future studies that test the efficacy of triglyceride-lowering interventions after ACS should provide clarity on whether triglyceride-rich lipoproteins should be a target of therapy after ACS.
Keywords: Acute Coronary Syndrome, Angina, Unstable, Cholesterol, Cholesterol Ester Transfer Proteins, Cholesterol, LDL, Coronary Disease, Double-Blind Method, Dyslipidemias, Fasting, Heptanoic Acids, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Ischemia, Lipoproteins, HDL, Lipoproteins, LDL, Myocardial Infarction, Pyrroles, Prognosis, Random Allocation, Secondary Prevention, Stroke, Sulfhydryl Compounds, Triglycerides
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