From the Guidelines
Apolipoprotein B (ApoB) is a valuable tool for cardiovascular risk stratification in diabetic patients, but it does not add further to the risk assessment when used in conjunction with LDL cholesterol, as evidenced by the 2019 American College of Cardiology/American Heart Association guideline 1. The use of ApoB for risk stratification is supported by the fact that it is a better index of the adequacy of LDL-lowering therapy and has less laboratory error in its determination, particularly in patients with hypertriglyceridaemia, as stated in the 2012 European guidelines on cardiovascular disease prevention in clinical practice 2. However, the 2019 guideline suggests that an elevated ApoB level ($130 mg/dL) is a risk-enhancing factor, particularly when accompanied by persistently elevated triglycerides, and denotes a high lifetime risk for atherosclerotic cardiovascular disease (ASCVD) 1. Regarding testosterone balance, both low and high testosterone levels can impact diabetes risk, with low testosterone in men associated with increased insulin resistance, visceral adiposity, and higher diabetes risk, and elevated testosterone in women (as seen in PCOS) facing increased diabetes risk due to worsened insulin sensitivity. For men with both diabetes and hypogonadism, testosterone replacement therapy may be considered to improve insulin sensitivity and glycemic control when testosterone levels are below 300 ng/dL, but should be monitored carefully for cardiovascular effects, prostate health, and hematocrit levels, with regular follow-up every 3-6 months. Key points to consider in the management of diabetic patients include:
- The use of ApoB as a risk stratification tool, with elevated levels indicating a higher risk of ASCVD
- The importance of testosterone balance in diabetes risk, with both low and high levels potentially impacting insulin sensitivity and glycemic control
- The potential benefits and risks of testosterone replacement therapy in men with diabetes and hypogonadism, and the need for careful monitoring and regular follow-up.
From the Research
Use of Apo A/B for Risk Stratification in Diabetics
- The ratio of ApoB to ApoA1 has been found to be associated with type 2 diabetes, and it was proposed as a new biomarker for type 2 diabetes predictions 3.
- A systematic review indicated that nontraditional apolipoprotein biomarkers apo B and apo B/apo A-I ratio resulted in significant improvement in long-term CVD risk assessment after controlling for traditional risk factors 4.
- The association between apoB/apoA1 ratio and type 2 diabetes may be nonlinear, with higher apoB/apoA1 ratio associated with higher prevalence of type 2 diabetes 3.
- Apolipoprotein B (apoB) was found to be a more accurate measure of cardiovascular risk and a better guide to the adequacy of lipid lowering than low-density lipoprotein cholesterol (LDL-C) or non-high-density lipoprotein cholesterol (HDL-C) 5.
Role of Testosterone Balance for DM Risk
- There is no direct evidence in the provided studies regarding the role of testosterone balance for DM risk.
- However, the studies focus on the relationship between apolipoproteins and diabetes, highlighting the importance of apolipoprotein biomarkers in risk stratification and management of diabetes 4, 3, 5, 6.
Apolipoprotein Status in Type 2 Diabetes Mellitus
- Dyslipidaemia in type 2 diabetes mellitus (T2DM) is characterized by high plasma triglyceride concentrations, reduced high‑density lipoprotein concentrations and increased small density low‑density lipoprotein concentrations 6.
- Complex metabolic disorders of apolipoproteins are present in T2DM, such as high plasma apoB, apoC‑II, apoC‑III and apoE concentrations, and low plasma apoA‑I and apoM concentrations, which are associated with dyslipidaemia and interrelated complications 6.
- Plasma concentrations of some apolipoproteins are also altered in T2DM with CVD or other complications, and several apolipoprotein polymorphisms are associated with diabetes susceptibility and/or lipid metabolism 6.