This content originally appeared on Diatribe. It was reissued with permission.
by Anna Widowsky and Matthew Garza
Medical review Charles M. Alexander, Maryland, FACP, Faith
Important takeouts:
- Diabetes is the main cause of chronic kidney disease, a condition in which the kidneys gradually lose their ability to function over time.
- Chronic kidney disease can lead to inaccurate measurements of A1C due to anemia and altered red blood cell production, which may lead to A1C being less reliable in blood glucose monitoring.
- Alternative solutions such as continuous glucose monitoring and time of range may provide more accurate insight into glycemic control.
Chronic kidney disease is a major diabetes-related complication that can lead to inaccuracies in A1C measurements, especially in advanced stages. If you have kidney disease, for some reason, we will explore what you can do to manage your blood sugar levels.
According to the Centers for Disease Control and Prevention (CDC), diabetes is one of the leading causes of chronic kidney disease, and is also known as diabetic kidney disease. Other risk factors include hypertension, a family history of kidney disease, obesity, and heart disease. Approximately one in three adults with diabetes may have chronic kidney disease, and many are unaware that they have it. Early stage kidney disease is often not symptomatic, so it is important to check your kidney health regularly. Medical professionals use a combination of urine and blood tests to check kidney function.
Treatment of diabetic kidney disease also includes treating chronically hyperglycemic levels, the underlying cause. A1C is an important measure used to assess overall diabetes management and risk of complications, but it has some limitations. A1C is one value that estimates glucose levels in the previous 2-3 months, so it does not provide details about daily glucose trends or informs about hypoglycemia (hypoglycemia). If someone has chronic kidney disease, the accuracy of the A1C value may be compromised.
It is important to consult with your healthcare provider about some of the challenges and limitations of A1C. Continuous glucose monitoring (CGM) can be used to describe supplementary measurements such as time within range using healthcare teams.
What is chronic kidney disease and how does it relate to diabetes?
The kidneys are an important organ in our body that causes several important functions, including:
- Remove waste from blood and other body fluids
- Balance the fluids and salts in the body
- Helps in managing your blood pressure
- Activates vitamin D, which helps keep your bones healthy
- Helps to produce hormones that stimulate the bone marrow to produce red blood cells
Chronic hyperglycemia levels, along with hypertension, can damage the small vascular filtering system of the kidneys, leading to renal failure.
For most people with chronic kidney disease, standard treatment focuses on slowing disease progression with lifestyle modifications and blood pressure-lowering medications. However, recent studies have shown that treatment with SGLT-2 and GLP-1 drugs that help lower blood sugar provides additional kidney and heart benefits. This is especially true for people with diabetes, but it is important to note that SGLT-2 drugs are not approved by the FDA in patients with type 1 diabetes. In recent years, SGLT-2 drugs have been added to treatment guidelines as an important disease-modifying therapy for people with type 2 diabetes and chronic kidney disease.
How does chronic kidney disease affect A1C in diabetic patients?
Recent studies have shown that A1C as a measure of glucose control is inaccurate for chronic kidney disease, particularly those with advanced chronic kidney disease (meaning renal function or EGFR below 30) or those on dialysis.
A1C measures the amount of glucose bound to hemoglobin in red blood cells over time. In chronic kidney disease, the higher the level of waste in the blood, the more likely it is to affect the way glucose binds to these red blood cells. A1C measurements depend on both blood glucose levels and red blood cell lifespan, so A1C measurements may not be reliable due to poor kidney function.
The KDIGO Clinical Practice Guidelines provide why chronic kidney disease overestimates or underestimates actual A1Cs in humans. In some cases, chronic kidney disease can lead to A1C, which appears to be higher than it actually is. For example, when the kidneys begin to break down, the body cannot remove the acids that accumulate in its body. This accumulation of acid (labeled as “metabolic acidosis” in the figure) speeds up the process of glucose binding to hemoglobin, making A1C appear high even when blood glucose levels are actually low.
Chronic kidney disease, on the other hand, can also lead to A1C, which appears to be lower than it actually is. This is because kidney disease can reduce red blood cell production and lead to anemia (lower than usual red blood cell count). This means that even if blood glucose is actually high, there is less hemoglobin for glucose to bind.
Furthermore, blood transfusions and drugs can have the same effect, which help your body produce more alternative red blood cells. Therefore, if you have a diagnosis of diabetes and are at risk of developing kidney disease, it is important to discuss your A1C target with your healthcare team.
Ask your healthcare team about the use of diabetes technologies such as CGM and automated insulin delivery (AID) systems. This helps track and manage your blood sugar levels.
If A1C is not reliable, how can you improve glycemic control for people with diabetes and chronic kidney disease?
Clinical practice guidelines still recommend the use of A1C to monitor blood glucose control in people with diabetes and chronic kidney disease, but recognize the limitations of A1C in patients with chronic kidney disease.
Replenishing A1C with other measurements of glucose control, such as time within range, may help to draw a more accurate picture of an individual’s blood glucose status. CGM also helps people monitor hypoglycemia by measuring time below a certain range of risk, as kidney failures and insulin decreases.
Further research into the use of CGM as a supplement to A1C is needed to help people with diabetes and chronic kidney disease to better understand how to improve glycemic control.
(TagStoTRASSLATE)A1C(T)GLP-1(T)Insulin(T)Intensive management(T)Kidney disease(T)Hypoglycemia(Hypoglycemia(T)SGLT-2(T)US Food and Drug Administration(FDA)
