Lowering the Triglyceride/High-Density Lipoprotein Cholesterol and its Association With the Beneficial Impact of Pioglitazone on Coronary Atherosclerosis in the PERISCOPE Study Is Likely Due to Lowering Insulin Resistance
Letter to the Editor
Introduction
Nicholls et al. (1), based on data from the PERISCOPE (Pioglitazone Effect on Regression of Intravascular Sonographic Coronary Obstruction Prospective Evaluation) study, reported that the favorable effects of pioglitazone on the triglyceride-to-high-density lipoprotein (trig/HDL) ratio correlated with delayed atheroma progression in diabetic patients. Nowhere in the paper do the authors recognize the association of the trig/HDL ratio with insulin resistance and the other manifestations of the metabolic syndrome. The trig/HDL ratio is a simple way to identify insulin-resistant individuals at increased risk of cardiovascular disease and has also been shown to predict the low-density lipoprotein particle size in Asian Indians (2–4).
Therefore, it is highly likely that the effect of pioglitazone in decelerating the formation of coronary artery atheroma was at least in part due to pioglitazone's ability to lower insulin resistance, which in turn reduces inflammation and post-prandial glucose—2 other potent and independent risk factors for atherosclerotic progression and adverse cardiovascular events (5,6).
1. : "Lowering the triglyceride/high-density lipoprotein cholesterol ratio is associated with the beneficial impact of pioglitazone on progression of coronary atherosclerosis in diabetic patients: insights from the PERISCOPE (Pioglitazone Effect on Regression of Intravascular Sonographic Coronary Obstruction Prospective Evaluation) study". J Am Coll Cardiol 2011; 57: 153.
2. : "Use of metabolic markers to identify overweight individuals who are insulin resistant". Ann Intern Med 2003; 139: 802.
3. : "Is there a simple way to identify insulin-resistant individuals at increased risk of cardiovascular disease?". Am J Cardiol 2005; 96: 399.
4. : "Accuracy of the ratio of triglycerides to high-density lipoprotein cholesterol for predicting low-density lipoprotein cholesterol particle sizes, phenotype B, and particle concentrations among Asian Indians". Am J Cardiol 2006; 97: 1007.
5. : "C-reactive protein and cardiovascular diseases—is it ready for primetime?". Am J Med Sci 2009; 338: 486.
6. : "Postprandial hyperglycemia/hyperlipidemia (postprandial dysmetabolism) is a cardiovascular risk factor". Am J Cardiol 2007; 100: 899.
