There are lots of articles about diabetes, as well as all kinds of information about anemia. But what if you have both? About 25 percent of people with diabetes have some level of anemia. This article explains how the two conditions interact.
What Is Anemia, and Why Is It Linked to Diabetes?
In anemia, there are fewer red blood cells than normal, resulting in less oxygen being carried to the body’s cells. People with anemia often feel tired or weak and may have difficulty getting through activities of daily living. Other symptoms include paleness, poor appetite, dizziness, lightheadedness, rapid heartbeat, and shortness of breath. Because these symptoms can also be associated with diabetes, they are sometimes not recognized as evidence of anemia.
Anemia may occur with diabetes because the hormone that regulates red blood cell production, erythropoietin (EPO), is produced by the kidneys. Kidney damage at several levels is a complication of diabetes, and one problem often leads to the other. Changes in the kidneys that occur with diabetes range from diabetic nephropathy all the way to chronic kidney disease. Early detection and treatment is essential to prevent or delay disease progression. Information in greater detail can be found at www.kidney.niddk.nih.gov.
Other causes of anemia are low levels of iron or other vitamins, as well as prolonged illness.
A simple blood test done during a doctor visit, called a complete blood count or CBC, is used to check for anemia. The two elements of the test that reveal anemia are hemoglobin and hematocrit. Hemoglobin is the part of red blood cells that carries oxygen to the cells. Hematocrit indicates the percentage of red blood cells in the blood.
How Does Anemia Affect Your Diabetes Care?
If you have anemia, your blood glucose tests may not be accurate. Studies that looked at blood glucose monitor accuracy found that low hematocrit levels can falsely increase glucose measurements, leading to monitor test results as much as 20 percent too high. Healthcare providers and patients need to be aware of this combination and consider it when responding to glucose levels, especially when treating patients on insulin.
Patients with anemia should ask their healthcare provider which blood glucose meter might be best for people with both anemia and diabetes. This question is currently being evaluated by the American Diabetes Association and the FDA.
Why Does Hematocrit Affect Glucose Monitor Accuracy?
All glucose monitors are designed to measure the level of glucose in the blood, but, unfortunately, not all blood is the same. A major difference between blood samples is the percentage of red blood cells, or hematocrit. The average hematocrit for men is slightly higher than the average for women. Young children tend to have a lower hematocrit than adults. As people age, hematocrit values usually are lower.
Low hematocrit is a common side effect of many illnesses and of drug therapies like metformin. Reductions in kidney function that occur in diabetes can also cause lower hematocrit values.
Hematocrit is part of the calculation that all glucose monitors use for measuring glucose. Monitor companies pick a “most likely” hematocrit value for their monitor calculation. If your hematocrit differs significantly from the hematocrit value used by the manufacturer, your monitor test results will be affected. The larger the difference between the manufacturer’s hematocrit value and your hematocrit value, the bigger the effect will be on your meter’s accuracy. Small changes in hematocrit are not a problem, but as patients move into anemia, the effect on accuracy is larger. Some of the newer meters have hematocrit corrections built in.
Treatment of Anemia in Diabetes
Iron supplementation is the most common treatment for anemia. When kidney disease is involved, there are additional options that you can discuss with your healthcare provider. If no cause other than reduced erythropoietin (EPO) production is found, anemia can be treated with a genetically engineered form of EPO that is usually injected under the skin two or three times a week. The US Food and Drug Administration recommends that patients treated with EPO therapy achieve a hematocrit between 30 and 36 percent.
Adjusting your diet to include foods rich in iron, folic acid, and vitamin B12 may also be helpful. Ask your diabetes educator or registered dietitian to help you adjust your meal plan to include these nutrients.
A number of steps can be helpful in preventing anemia. Keep your blood glucose at the target levels set by you and your healthcare provider, and maintain your blood pressure under 130/80. Control your lipids, and work with your healthcare team to manage your cholesterol and triglyceride levels. Finally, eat a well-balanced diet that includes foods containing iron.
Ever since the Diabetes Control and Complication Trial in 1993, studies have shown that the largest influence in diabetes care is the person with diabetes. Your participation in your own care is critical, so it’s important to be aware of how anemia can affect your diabetes.