What is an HbA1c test?
An HbA1c test is used to diagnose and monitor diabetes by measuring the body’s average blood sugar level over the past three months. It measures the amount of glucose in your bloodstream. More specifically, it checks the hemoglobin, an iron-rich protein that transports oxygen and nutrients throughout the body.
Glucose, a sugar the body uses for energy, binds to this hemoglobin, creating “glycated hemoglobin” molecules. The higher your blood glucose level, the more glucose attaches to the hemoglobin, not effectively getting into the blood cells to be used for energy. Since hemoglobin cells last about 90 days, the HbA1c provides an overall picture of your blood sugar control for the previous three months.
In non-diabetics, HbA1c levels stay below 5.7%. An HbA1c between 5.7% and 6.5% suggests prediabetes. An HbA1c of 6.5% or higher usually indicates diabetes. Very poor, or dangerous, levels of hbA1c are 8.7% and higher. In short, a high HbA1c level shows that your body has difficulty regulating glucose levels.
This article explains what happens to your body when your HbA1c is too high. It also details what different HbA1c levels mean and complications from dangerously high HbA1c’s. Most importantly, it shows how monitoring your HbA1c levels can help to prevent diabetic complications.
What Is Considered a High HbA1c?
HbA1c level results show the percentage of glucose and hemoglobin bound together in your bloodstream. For example, a 5% HbA1c indicates that five out of every 100 hemoglobins are “glycated” (covered in sugar).
The HbA1c ranges for Normal, Prediabetes, and Diabetes are:
- Normal: Less than 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
What Are Normal HbA1c Levels?
If your HbA1c falls under the “Normal” category, you are considered “diabetes-free”, with ‘very good” glycemic control and little to no risk of diabetes ever manifesting. Keep up the good work! Keep getting in daily activity that will get your heart pumping for 30 minutes a day. Keep making healthy food and drink choices, like drinking more water, and incorporating more whole foods and less processed foods in your diet. If, however, there are any risk factors of diabetes in your health history, including, having a parent or sibling with diabetes, or being over the age of 45, it is still wise to get your HbA1c checked every three years. As you get older, HbA1c levels naturally rise. Talk to your health care provider to find out when you should get your HbA1c checked next if you are in the normal range.
HbA1c Levels In People With Prediabetes
If your HbA1c is in the “Prediabetic” range, you are considered to have “good glycemic control”. There is, however, room for improvement at this range. Prediabetes is one of the main risk factors for type 2 diabetes. Thankfully, lifestyle changes can reverse prediabetes and prevent the development of full-blown type 2 diabetes. Nutritional changes, such as switching to whole grains instead of processed grains, watching carbohydrate intake, and removing seed oils and saturated fats can help restore healthy glycemic control. Increased daily moderate activity, such as taking a brisk walk after every meal and moderate weight loss of just 5% of your body weight can help improve blood sugar control to prevent diabetes. Talk to your health care provider to find out when you should get your HbA1c checked next if you are in the prediabetes range. Typically, it would be every 3-6 months.
What are HbA1c Levels in People with Diabetes?
If your HbA1c is in the “Diabetes” range, an HbA1c between 6.5% and 7.5% is typically considered “good glycemic control”. This control can be achieved by taking diabetes medications as prescribed, adopting a nutritious meal plan with the help of a diabetes nutritionist, and seeing a Certified Diabetes Educator or Nurse regularly to help navigate the uncertainty this disease can bring into your life. It is at this range that most diabetes complications can be kept at bay, for the most part. It is important to note, however, that blood vessel damage can begin at 7%, so medical intervention is key here. Older adults, however, are at a greater risk of developing low blood sugar, known as hypoglycemia, which can lead to falls. To address this, the target range is adjusted upward to <8%.
What Is a Poor, or Very Poor A1c level?
Research shows that an HbA1c between 8.1% and 8.6% significantly increases the risk of diabetic complications and is considered “poor glycemic control”. For people with diabetes, having an HbA1c of 8.7% or higher is considered “very poor glycemic control”. It is at this point where the risks of severe diabetic complications, such as heart disease, stroke, and blindness, or even death, can occur. Immediate medical intervention is needed at this stage.
Complications of High A1c Levels
Heart Disease and Stroke:
People with diabetes are at an increased risk of heart disease. Chronic high blood sugar levels can damage nerves and blood vessels that keep the heart healthy. Diabetics also tend to develop heart disease younger than those without diabetes. The longer you have diabetes, the more likely it is you also have heart disease.
Coronary heart disease is the most common type of heart disease. It is caused by the buildup of plaque in the walls of the coronary arteries—the blood vessels that supply blood and oxygen to the heart.
Plaque—cholesterol, fat, and cellular waste—builds up in a process known as atherosclerosis. This decreases blood flow to the heart, which can cause a heart attack.
Decreased blood flow to the brain can also cause a stroke. Diabetes is linked to an increased risk of stroke and higher rates of mortality from stroke.
Diabetes also increases your risk of other heart disease risk factors. These include:
- High blood pressure
- High LDL cholesterol
- High triglycerides
- Heart failure
High blood sugar can cause eye damage, leading to poor vision and vision loss. Over time, high blood glucose levels damage the tiny blood vessels in the back of your eyes. Damaged blood vessels may leak fluid and cause swelling. New blood vessels that form may be weak. These blood vessels can bleed into the middle part of the eye, cause scarring, or dangerously increase pressure inside your eye. Diabetic eye changes are often without symptoms at first. Eye damage can begin during the prediabetes (7% HbA1c) stage and typically progresses slowly.
Diabetic eye diseases can largely be prevented by managing your blood sugar levels. Finding and treating diabetic retinopathy early can reduce the risk of blindness by 95%. A full, dilated eye exam helps find and treat eye problems early—before much vision loss can occur. Adults with type 2 diabetes should get an eye exam soon after diagnosis and a dilated eye exam every year after.
Common diabetic eye diseases include:
- Diabetic Retinopathy-most common cause of vision loss
- Diabetic Macular Edema-fluid retention in the retina
Nerve damage caused by diabetes is called diabetic neuropathy. High blood sugar damages your nerves, which stop sending messages to different parts of your body. Nerve damage can cause problems ranging from mild numbness to severe pain. Half of all people with diabetes have nerve damage. Maintaining a lower Hba1c is the best way to prevent or delay diabetic nerve damage.
Common types of neuropathy in people with diabetes include:
- Peripheral Nerve Damage–This affects hands, feet, legs, and arms. The most common type of diabetic nerve damage. Generally starts on both feet at once.
- Autonomic Nerve Damage: This affects the heart, bladder, stomach, intestines, sex organs, or eyes.
- Proximal Nerve Damage: This affects nerves in the thighs, hips, buttocks, legs, abdomen, and chest.
- Focal Nerve Damage: This affects single nerves, most often in your hand, head, torso, or leg.
Symptoms of nerve damage include:
- Burning pain
- Muscle cramps
- Poor balance
- Problems with coordination
- Sharp, shooting pains
- Tingling or pins and needles
- Urinary or bowel incontinence
High HbA1c levels increase the risk of diabetic nephropathy, or kidney disease. One in three adults with diabetes has diabetic kidney disease. Like with the eyes, heart, and nerves, high blood glucose damages blood vessels in the kidneys. When that happens, the kidneys are less able to filter out waste products and extra fluid. Furthermore, many people with diabetes also develop high blood pressure, which can also damage the kidneys.
Diabetic nephropathy typically does not have any early symptoms. As the condition worsens, it can cause:
- Confusion and difficulty concentrating
- High blood pressure
- Loss of appetite
- Frequent urination
- Nausea and vomiting
- Persistent itching
- Protein in the urine
- Shortness of breath
- Swollen feet, ankles, hands, or eyes
High blood glucose also increases the sugar content in your saliva. This exposes the mouth, teeth, and gums to more sugar, germs, and plaque. This can irritate gums, causing gum disease. In addition to gum disease, your jaw, tongue, and other mouth tissue can be affected. Some of the first signs of gum disease are swollen, tender, or bleeding gums. You may not have any overt signs of gum disease until serious damage has occurred. The best defense is to brush your teeth twice a day and visit your dentist twice a year.
The most common gum disease and other mouth problems that people with diabetes have include:
- Gingivitis–unhealthy or inflamed gums
- Oral burning
- Thrush-oral yeast infection
- Xerostomia-dry mouth
How to Lower High HbA1c Levels?
Managing blood sugar to keep your HbA1c in your target range can prevent diabetic complications. If your HbA1c is high, work with your healthcare team to develop a plan. Blood-sugar lowering strategies primarily include self-management tools and making healthy choices.
At-Home Blood Sugar Monitoring
HbA1c testing is an important tool for managing diabetes but doesn’t replace at-home blood sugar monitoring. Research shows a direct link between more frequent blood sugar testing and lower HbA1c levels. Talk to your healthcare provider about how often you should test your blood sugar. In addition, keeping a blood sugar log can provide valuable information to you and your health team. This can help determine what (if any) changes to make to your treatment plan.
At-home monitoring can be done with either a glucometer or a continuous glucose monitoring system (CGMS).
- Glucometer blood sugar meter: Uses test strips and a tiny sample of blood from your finger. It shows your approximate blood sugar at the time of testing.
- CGMS: Uses a tiny sensor under the skin that continuously checks your blood sugar. It transmits readings over Bluetooth to your smartphone or other devices.
Healthy Eating and Meal Tracking
Diet has a huge impact on your blood sugar. In particular, processed carbohydrates like white bread, rice, potatoes, and sweets raise your blood sugar. During digestion, the body breaks carbohydrates down into glucose. One way to find out how certain foods affect your blood sugar is to test two hours after eating. Keeping a food journal along with blood sugar logs helps identify high blood sugar patterns. This can help you spot patterns, and manage your glucose levels better to inevitably lower your HbA1c. A diabetes nutritionist or Certified Diabetes Educator can help you learn how to balance meals for lower blood sugar.
Stress Relief Techniques
Managing stress is crucial to staying healthy in general and can particularly help people with diabetes. Studies have shown that acute stress raises blood sugar levels by spurring glucose production and hindering insulin sensitivity. Also, when under severe stress, Cortisol, the stress hormone, is released, for the “fight or flight” response. This automatically raises your blood sugar levels. Better control of stress can positively impact blood sugar levels.
Some stress relief techniques include:
- Talk therapy
- Nature walks
- Listening to music or birdsong
Get regular exercise?
Exercise helps to lower glucose levels by improving insulin sensitivity. Insulin is a hormone that helps glucose from the blood enter your muscles and organs. Research shows moderate exercise improves insulin sensitivity for up to 24 hours. When you exercise, your muscles use glucose for energy. This lowers glucose levels in the bloodstream. Studies show long-term regular physical activity has a positive impact on HbA1c levels. Exercise also helps to spur weight loss, reduce stress, and improve cardiovascular health. The more exercise, the greater HbA1c reduction. Most people with diabetes should aim for at least 150 minutes of moderate-intensity exercise each week. But, watch for lows! People who take insulin or other medications that lower blood sugar should monitor their blood sugar more closely during and after exercise to prevent hypoglycemia.
If you cannot lower your HbA1c through lifestyle changes, medication may be warranted. Prescription medication for type 2 diabetes works in a few different ways. Some help your body make more insulin, and others help your body use the insulin it makes. Some people with type 2 diabetes use insulin to manage their blood sugar. Remember to take your medication as prescribed and check with your healthcare team if you have any questions.
If you do end up with a diabetes diagnosis after having HbA1c testing performed, keep in mind that treatments are better than ever! With careful attention to your unique diabetes treatment plan and following your healthcare provider’s instructions to the letter, you can lower your HbA1c levels, reduce risks of diabetes complications, and live your best life!