NEW YORK (Reuters Health) – The well-known association between poor glycemic control and low HDL cholesterol in patients with type 2 diabetes is independent of obesity and hypertriglyceridemia, according to a study conducted in Italy.

Obesity and hypertriglyceridemia are known determinants of low HDL cholesterol and are frequently seen in patients with poorly controlled diabetes, Dr. Sebastiano Filetti and colleagues explain in the August issue of the journal Diabetes Care.

The investigators tested the hypothesis that glycemic control is independently associated with HDL cholesterol in a cross-sectional study of 1,819 type 2 diabetic patients with triglyceride levels less than 400 mg/dL from diabetes centers in San Giovanni Rotondo, Catanzaro and Rome.

The prevalence of low HDL cholesterol — defined as less than 40 mg/dL in men or less than 50 mg/dL in women — ranged from 28% in Rome to 34% in Catanzaro to 55% in San Giovanni Rotondo.

At all three centers, hemoglobin A1C levels tended to be higher in patients with low HDL cholesterol than in those with higher HDL cholesterol levels, and this difference was statistically significant in two of the three centers, the researchers report.

In a pooled analysis, they found that a 1% increase in hemoglobin A1C values significantly increased the risk for low HDL cholesterol, with an odds ratio of 1.17 (p = 0.00072). The odds ratio did not change in a multivariate analysis that included age, sex, smoking status, and lipid-lowering therapy.

Of note, “the strength of this association was also maintained” when obesity (BMI 30 kg/m² or greater) and hypertriglyceridemia (150 mg/dL or greater) were added to the multivariate model (OR, 1.12; p = 0.00017).

Dr. Filetti and colleagues note in their report that nearly half of all type 2 diabetic patients have low HDL cholesterol levels. To their knowledge, their study provides the first evidence that impaired glycemic control is an important independent risk factor for low HDL cholesterol in type 2 diabetes.

“If confirmed in future studies, this observation may provide an additional means for establishing optimal glycemic targets tailored to individual patient characteristics,” they conclude.

Reference:
Diabetes Care 2009;32:1550-1552.