Triglycerides and TG-HDL Ratio Help Identify Insulin Resistance in Overweight Patients

Laurie Barclay, MD

November 20, 2003

Nov. 20, 2003 — Triglycerides and triglyceride–high-density lipoprotein (HDL) ratio are good surrogate markers for identifying insulin resistance in overweight patients, according to the results of a cross-sectional study published in the Nov. 18 issue of the Annals of Internal Medicine.

"Insulin resistance is more common in overweight individuals and is associated with increased risk for type 2 diabetes mellitus and cardiovascular disease," write Tracey McLaughlin, MD, and colleagues from Stanford University School of Medicine in Stanford, California. "Given the current epidemic of obesity and the fact that lifestyle interventions, such as weight loss and exercise, decrease insulin resistance, a relatively simple means to identify overweight individuals who are insulin resistant would be clinically useful."

The investigators measured body mass index (BMI), fasting glucose, insulin, lipid and lipoprotein concentrations, and insulin-mediated glucose disposal as determined by the steady-state plasma glucose concentration during the insulin suppression test in 258 nondiabetic, overweight volunteers with BMI of 25 kg/m 2 or greater.

The most useful metabolic markers for insulin-resistance, defined as being in the top tertile of steady-state plasma glucose concentrations, were plasma triglyceride concentration, ratio of triglyceride to HDL cholesterol concentrations, and insulin concentration.

Based on receiver-operating characteristic curve analysis, the optimal cut-points were 1.47 mmol/L (130 mg/dL) for triglyceride, 1.8 in SI units (3.0 in traditional units) for the triglyceride–HDL cholesterol ratio, and 109 pmol/L for insulin. These cut-points achieved a sensitivity of 67%, 57%, and 68%, and specificity of 64%, 71%, and 85%, respectively.

The ability of these markers to identify insulin-resistance was similar to that of the criteria proposed by the Adult Treatment Panel III to diagnose the metabolic syndrome, which had a sensitivity of 52% and specificity of 85%.

Study limitations include primarily white study sample precluding generalization of the findings to other ethnic groups, and limited sensitivity and specificity of the markers studied.

"Three relatively simple metabolic markers can help identify overweight individuals who are sufficiently insulin resistant to be at increased risk for various adverse outcomes," the authors write. "In the absence of a standardized insulin assay, we suggest that the most practical approach to identify overweight individuals who are insulin resistant is to use the cut-points for either triglyceride concentration or the triglyceride–HDL cholesterol concentration ratio.... Early identification of high-risk patients might lead to earlier, more successful interventions, such as weight loss or prevention of further weight gain."

The National Institutes of Health supported this study. The authors report no potential financial conflicts of interest.

Ann Intern Med. 2003;139:802-809

Reviewed by Gary D. Vogin, MD


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