From the Guidelines
A person's fasting glucose should ideally be less than 100 mg/dL (5.6 mmol/L). This is considered the normal range for fasting blood glucose, as indicated in the study by 1. A reading between 100-125 mg/dL (5.6-6.9 mmol/L) indicates prediabetes, while a fasting glucose of 126 mg/dL (7.0 mmol/L) or higher on two separate tests suggests diabetes.
Key Points to Consider
- For accurate measurement, fasting should be done for at least 8 hours prior to testing, typically overnight, as suggested by 1.
- Water is permitted during this fasting period, but food, beverages with calories, and most medications should be avoided.
- Fasting glucose is an important indicator of how well your body processes sugar when not actively digesting food.
- Elevated fasting glucose levels may indicate insulin resistance or insufficient insulin production, which are hallmarks of diabetes.
- Regular monitoring of fasting glucose is particularly important for those with risk factors such as family history of diabetes, obesity, or previous gestational diabetes, as noted in 1.
Glycemic Targets
- The American Diabetes Association recommends lowering HbA1c to < 7.0% in most patients to reduce the incidence of microvascular disease, as stated in 1.
- More stringent HbA1c targets (e.g., 6.0–6.5%) might be considered in selected patients, while less stringent HbA1c goals (e.g., 7.5–8.0% or even slightly higher) are appropriate for patients with a history of severe hypoglycemia, limited life expectancy, advanced complications, extensive comorbid conditions, and those in whom the target is difficult to attain despite intensive self-management education, repeated counseling, and effective doses of multiple glucose-lowering agents, including insulin, as discussed in 1.
Importance of Individualized Treatment
- Treatment targets should be individualized based on the patient's desires, values, and medical history, as emphasized in 1.
- The ease with which more intensive targets are reached influences treatment decisions, and lower targets are attractive if they can be achieved with less complex regimens and no or minimal adverse effects, as noted in 1.
From the Research
Fasting Glucose Levels
- The ideal fasting glucose level is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, the studies discuss the effects of various medications on fasting plasma glucose levels in patients with type 2 diabetes.
- For example, short-acting GLP-1 RAs (exenatide b.i.d., lixisenatide) have reduced effectiveness on overnight and fasting plasma glucose, while long-acting GLP-1 RAs (liraglutide, once-weekly exenatide, dulaglutide, albiglutide, and semaglutide) have more profound effects on overnight and fasting plasma glucose and HbA1c 2.
- Glimepiride, a sulfonylurea, has been shown to be safe and effective in reducing fasting and postprandial glucose levels, as well as glycosylated hemoglobin concentrations 3.
- Metformin, a first-line therapy for type 2 diabetes, has been shown to have beneficial effects on hemoglobin A1c, weight, and cardiovascular mortality compared to sulfonylureas 4.
Medication Effects on Fasting Glucose
- GLP-1 RAs have been shown to effectively lower plasma glucose levels, including fasting glucose, and have been recommended as the preferred first injectable glucose-lowering therapy for type 2 diabetes 2.
- Sulfonylureas, such as glimepiride, have been shown to be effective in reducing fasting glucose levels, but may have a higher risk of hypoglycemia and weight gain compared to other medications 3, 6.
- Metformin has been shown to have a beneficial effect on fasting glucose levels, and is often used as a first-line therapy for type 2 diabetes 4, 5.