From the Guidelines
A hemoglobin A1c level of 4.6% is considered below the normal range and may indicate hypoglycemia or certain medical conditions, and patients with this reading should consult their healthcare provider to determine the cause and appropriate management. According to the American College of Physicians guidance statement 1, the target HbA1c level for most patients with type 2 diabetes should be between 7% and 8%, and clinicians should consider deintensifying pharmacologic therapy in patients who achieve HbA1c levels less than 6.5%. The evidence from several large, long-term randomized controlled trials, including the ACCORD, ADVANCE, UKPDS, and VADT trials 1, suggests that intensive glycemic control to achieve HbA1c levels below 7% does not reduce death or macrovascular events over about 5 to 10 years of treatment, but does result in substantial harms, including hypoglycemia. Therefore, patients with a low HbA1c level of 4.6% should be evaluated for potential causes, such as hypoglycemia or certain medical conditions, and managed accordingly to prevent complications and improve quality of life. Some potential causes of a low A1c include certain anemias, liver disease, kidney failure, increased red blood cell turnover, or excessive treatment with diabetes medications if being treated for diabetes 1. If the patient is taking insulin or sulfonylureas, their doctor might need to reduce their dosage to prevent hypoglycemia, and additional testing may be recommended to determine the cause, including a complete blood count, liver function tests, or kidney function assessment 1. Overall, the management of a low HbA1c level of 4.6% should prioritize the prevention of complications, improvement of quality of life, and careful evaluation of potential causes to determine the best course of treatment.
From the Research
Implications of Low Hemoglobin A1c (HbA1c) Levels
- A low HbA1c level of 4.6 may have several implications, including:
- Increased risk of severe hypoglycemia in patients with type 1 diabetes, although this association has decreased in recent years 2
- Potential for fulminant type 1 diabetes mellitus, a rare condition characterized by rapid pancreatic β-cell destruction 3
- Association with liver diseases, hospitalization, and all-cause mortality in apparently healthy individuals 4
- Increased risk of falls in older adults with type 2 diabetes who use insulin, particularly if HbA1c levels are <6% 5
Clinical Considerations
- Low HbA1c levels can be caused by various factors, including:
- In cases of extremely low HbA1c results, clinical laboratorians should investigate the underlying cause and consider alternative tests or increased health surveillance 4
- HbA1c may not be a reliable marker of glycemic control in patients with certain conditions, such as fulminant type 1 diabetes mellitus or beta-thalassemia minor 6, 3