More Time in Range Can Lower Your Risk of Kidney Damage
By Frida Velcani
Studies show that if you have diabetes, increasing your Time in Range (TIR) can lower your risk of developing kidney disease. Learn how kidney disease is diagnosed, why A1C has limitations for people with CKD, and the link between your TIR and your risk for kidney disease.
Chronic kidney disease (CKD) occurs when your kidneys cannot properly filter the fluids that pass through them. This can be caused by damage to the blood vessels in your kidneys that happen as a result of sustained high blood sugar levels.
There are several ways to reduce your risk for CKD including getting screened regularly, managing your blood pressure, exercising regularly, eating a well-balanced diet, and stopping smoking. However, one of the greatest things you can do is to manage your glucose levels by increasing your Time in Range. Studies show that there is a link between more Time in Range and a decreased risk for CKD. But before diving into this link and the importance of Time in Range, it’s important to understand how CKD is diagnosed to understand the research that shows Time in Range can have an impact on these diagnostic criteria.
How do healthcare professionals identify CKD?
There are two important lab tests that you can get which can show how your kidneys are functioning and whether or not there is kidney damage. To learn more about these lab tests, read “Get to Know Your Lab Tests: A1C, eGFR, UACR, and More.”
One way healthcare professionals can determine kidney damage is by examining the amount of albumin (a type of protein) released into the urine, also known as the urine albumin-to-creatinine ratio (uACR). Albuminuria occurs when there is too much albumin in the urine. Because healthy kidneys typically do not allow albumin to pass from the blood into the urine, this can be an early marker of kidney damage. This is why it is important to get this tested regularly.
A urine test compares how much albumin, relative to creatinine, is present in your urine. Creatinine is the waste product in urine that comes from our muscles using up energy on a normal, day-to-day basis.
A uACR less than 30 mg/g is common for someone without kidney damage
A uACR of 30 to 300 mg/g refers to more albumin than is typical and is sometimes called microalbuminuria
A uACR greater than 300 mg/g is severely elevated and is generally called albuminuria
Another important test is a blood test that measures your estimated glomerular filtration rate or eGFR. This test can provide insight into how well your kidneys are functioning. Together these two tests help healthcare professionals identify CKD. Have you recently had one or both of these tests done and want to learn more? Read our article, “Recently Screened for Kidney Disease? Now What?”
What is the relationship between TIR and kidney disease?
Experts in the field are conducting research on the value of continuous glucose monitoring (CGM) in helping reduce the prevalence of diabetes-related complications. Evidence suggests that improvements in your Time in Range (TIR) could lower your risk for developing kidney disease. CGM can also be a helpful tool for monitoring hypoglycemia, which can occur when the kidneys begin to fail and break down less of the insulin that one is either making or taking by injection, pump or inhalation.
Some important findings from research on this subject include:
In one study that looked at the DCCT (Diabetes Control and Complications Trial) data set, researchers found that participants with type 1 diabetes who developed microalbuminuria had an average TIR of 32% – ten percentage points lower than the average TIR for those who did not develop kidney disease (42%).
In this same study, the risk for developing microalbuminuria increased by 40% for every 10% decrease in TIR.
In another study in people with type 1 diabetes, researchers found that a person’s uACR decreased by 19% for every 10% increase in TIR in people with type 1 diabetes.
Similar results could also be found in those with type 2 diabetes. In a population of 866 people with type 2 diabetes, their albuminuria risk was 6% lower for every 10% increase in TIR.
The researchers also found that more time spent in hyperglycemia and severe hyperglycemia (over 180 mg/dl and 250 mg/dl respectively) was also found to lead to a higher risk of developing albuminuria.
Additionally, in a study of 836 people with type 2 diabetes and kidney disease, researchers found that having a TIR less than 40% led to an increased risk for uACR abnormalities.
Finally, when looking at an older population of 281 people with type 2 diabetes, there was an association between a person’s uACR and their TIR – as their TIR went down with increasing age and disease duration, their uACR increased.
To keep your kidneys healthy, be sure to keep track of your A1C, blood pressure, and cholesterol. These are sometimes called the “ABC’s of diabetes.” It is especially important to get your kidneys checked often by your healthcare professional if you have diabetes, high blood pressure, heart disease, or a family history of CKD.
Can CKD impact your glucose measurements?
One of the reasons why healthcare professionals are looking to the connection between Time in Range and CKD is because even though A1C is an important metric for evaluating overall diabetes management and your risk for complications it also has limitations.
Research also shows that your A1C measurement may be less accurate if you have CKD due to changes in your body’s red blood cells. When the kidneys begin to fail, there is a buildup of acid in the body (called metabolic acidosis). In addition, a process called carbamylation can alter the proteins (called hemoglobin) in your red blood cells. Both of these processes can produce higher A1C levels, even when hyperglycemia does not occur.
Interestingly, having CKD can also lead to an A1C that appears lower than it might actually be. This is caused by your body not producing enough red blood cells (resulting in anemia) or blood transfusions or medications that make your body replace red blood cells faster than they would be replaced in a person without CKD. The result of this increased red blood cell turnover is a reduced A1C.
You can learn more about how CKD affects your A1C measurements here.
Talk to your doctor about your risk for CKD and how you can reduce this risk using metrics like Time in Range.
This article is part of a series on Time in Range.
The diaTribe Foundation, in concert with the Time in Range Coalition, is committed to helping people with diabetes and their caregivers understand time in range to maximize patient’s health. Learn more about the Time in Range Coalition here.