From the Guidelines
Anemia can significantly impact Hemoglobin A1c (HbA1c) results, with certain types of anemia falsely elevating or lowering HbA1c levels, and therefore alternative methods for monitoring glucose control should be considered in patients with known anemia. The effect of anemia on HbA1c results depends on the type of anemia present.
- In iron-deficiency anemia, HbA1c levels are often falsely elevated, as stated in the study 1, which can lead to overestimation of blood glucose control.
- Conversely, in hemolytic anemia or conditions with increased red blood cell turnover, HbA1c levels may be falsely lowered due to the shortened lifespan of red blood cells, which reduces the time available for glycation to occur, as reported in the study 1. Other types of anemia, such as those caused by vitamin B12 or folate deficiency, can also affect HbA1c measurements by altering red blood cell production and lifespan. For patients with known anemia, healthcare providers should consider alternative methods for monitoring glucose control, such as fructosamine tests, glycated albumin measurements, or continuous glucose monitoring, as recommended in the study 1. It's essential to correct the underlying anemia before relying on HbA1c for diabetes management decisions, as treating the anemia often normalizes the HbA1c values to more accurately reflect actual glycemic control, as suggested by the study 1. Key points to consider when interpreting HbA1c results in patients with anemia include:
- The type of anemia present and its potential impact on HbA1c results
- The use of alternative methods for monitoring glucose control
- The importance of correcting the underlying anemia to ensure accurate HbA1c results, as emphasized in the study 1.
From the Research
Effect of Anemia on HbA1c
- Anemia can affect the accuracy of HbA1c measurements, as it can lead to a shorter lifespan of red blood cells 2, 3, 4, 5.
- In patients with anemia, HbA1c levels may be falsely low, which can delay treatment for poorly-controlled diabetes 2.
- The presence of anemia can also affect the correlation between HbA1c and fasting glucose levels, making HbA1c a less reliable indicator of glycemic control 5.
- Anemia can be a marker of a catabolic state with altered plasma protein turnover, which can also affect indirect measures of glycemic exposure such as fructosamine and glycated albumin 5.
Alternative Measures of Glycemic Control
- Fructosamine and glycated albumin are alternative measures of glycemic control that are not affected by anemia or red blood cell disorders 2, 3, 4.
- These measures can provide a more accurate assessment of glycemic control in patients with anemia or other conditions that affect HbA1c measurements 2, 3, 4.
- However, these measures also have their own limitations and may not be suitable for all patients, such as those with disorders of albumin metabolism 3, 4.
Clinical Implications
- Clinicians should be aware of the potential effects of anemia on HbA1c measurements and consider alternative measures of glycemic control in patients with anemia or other conditions that affect HbA1c 2, 3, 4, 5.
- Continuous glucose monitoring or self-monitoring of blood glucose may be useful in assessing glycemic control in patients with anemia or CKD 5.