Purpose: Type 2 diabetes (T2D) increases the risk of cardiovascular disease (CVD). Achieving glycated hemoglobin (HbA1c) below 7.0 % in newly diagnosed T2D reduced CVD risk. It is uncertain whether HbA1c below 7.0 % in T2D with varying duration of diabetes also reduced CVD risk. This study investigated the associations between hyperglycemia and abnormal lipid metabolism in patients with T2D.
Methods: We conducted a survey of 19,757 outpatients with T2D who were 18 years of age or more and treated with oral antidiabetes drugs (OADs) alone or OADs combined with other drugs. The coverage rates of the 3A hospitals were 74.4 % for Beijing (n = 32), 76 % for Shanghai (n = 22), 55 % for Tianjin (n = 11) and 29.3 % for Guangzhou (n = 12). Abnormal lipids were defined as ≥2.6 mmol/L for low-density lipoprotein (LDL) cholesterol, ≤1.0 mmol/L in men and ≤1.3 mmol/L in women for high-density lipoprotein (HDL) cholesterol; ≥1.7 mmol/L for triglyceride. Logistic regression stratified on city and hospital was used to obtain odds ratio (OR) of hyperglycemia for abnormal lipids.
Results: The patients had 4.0 (interquartile range 1.7-8.8) years of duration of diabetes. HbA1c ≥7.0 % was associated with increased risk of high LDL cholesterol (multivariable OR of ≥7.0 vs. <6.0 %:1.37, 95 % confidence interval 1.19-1.57). HbA1c ≥6.5 % was associated increased risk of high triglyceride. HbA1c was associated with low HDL cholesterol in a J-shaped manner, whereby HbA1c levels of <6.0 % as well as ≥6.5 % being associated with increased risk of low HDL cholesterol.
Conclusions: Hyperglycemia defined as HbA1c ≥7.0 % increased risk of high LDL cholesterol in T2D.