Possible Complications

When blood glucose (sugar) levels are out of the normal range, complications may develop. These include the following:

  • In the short-term:
    • Hypoglycemia (can lead to neurological problems and possible loss of consciousness)
    • Hyperglycemia
    • High triglycerides
  • In the long-term:
    • Blindness
    • Kidney disease (can lead to a need for ]]>dialysis]]>)
    • Heart disease (including ]]>heart attacks]]>)
    • Stroke
    • Nerve disease
    • Poorly healing wounds

Careful control of your blood glucose levels can lower your chances of developing these complications. Also, ask your doctor if there are medicines that you should take to further reduce your risk.



Hypoglycemia]]> is low blood sugar. It is more common in people who take insulin to control their glucose levels. But, it can also occur in people who take oral medicine, most commonly sulfonylureas. Hypoglycemia can be caused by any of the following:

  • Taking too much insulin or oral diabetes medicine
  • Skipping or delaying a meal, or eating a smaller meal than usual
  • Exercising harder or longer than your usual pattern


Hypoglycemia can be managed if you recognize the symptoms and treat them right away. The symptoms of hypoglycemia include:

  • Shakiness
  • Dizziness
  • Sweating
  • Hunger
  • Headache
  • Pale skin color
  • Sudden moodiness or behavior change (eg, crying for no apparent reason)
  • Clumsy or jerky movements
  • Confusion or difficulty paying attention
  • Tingling sensations around the mouth
  • ]]>Seizures]]>
  • Loss of consciousness or ]]>fainting]]>

If you think you have hypoglycemia, test your blood with a blood glucose monitor. If the glucose level is below the range your doctor said was safe, then treat hypoglycemia. In some cases, you may recognize the symptoms of hypoglycemia and choose to treat it without testing your blood. But, it is best to use the glucose monitor to make sure that the symptoms you have are really due to hypoglycemia.

Safety ranges for glucose levels vary from person to person. The ranges are based on your age and medical conditions. If you do not know what your safe blood glucose range is, ask your doctor.


The goal of treating hypoglycemia is to quickly raise your blood glucose level to within your safe range. Ask your doctor what the best method of quickly treating hypoglycemia is for you. Common methods of self-treating hypoglycemia include eating or drinking some form of sugar, such as:

  • Glucose tablets
  • Cola with sugar (not diet cola)
  • ½ cup of fruit juice
  • 5-6 pieces of hard candy

To be prepared, you should always have some type of sugar with you. Wait 15-20 minutes after eating sugar, then retest your glucose level. If it is still too low, repeat the treatment. If you pass out from hypoglycemia, you will need emergency treatment. At the hospital, the doctor may give you an injectable hormone called glucagon.

If you have symptoms or episodes of hypoglycemia, discuss the events around the episodes with your doctor. Also, review your medicine to see if it needs adjusting. Talk to your doctor about ways you can prevent hypoglycemia.



Hyperglycemia is high blood sugar. Long-term hyperglycemia is the major cause of many of the complications that occur in people with diabetes. Hyperglycemia occurs when you do not have enough insulin to remove the glucose in your body, or when your body does not use insulin properly. It can be caused by:

  • Taking too little insulin or oral medicine
  • Eating a larger meal than usual
  • Experiencing stress from an illness or from factors in daily life


Hyperglycemia should be treated right away to avoid further complications. The signs and symptoms include:

  • Frequent urination
  • Increased thirst
  • Blurred vision
  • Unexplained weight loss

If hyperglycemia is not promptly treated, it can lead to life-threatening ketoacidosis. This condition happens when glucose levels are so high that very little sugar is available in the cells for energy. The body starts breaking down stored fat for energy. The by-products of this fat breakdown are ketone bodies, acids that build up in the blood and cause ketoacidosis. The condition is more common in type 1 diabetes]]>. But, it does rarely occur in type 2 diabetes.



Chronic high blood glucose levels, as well as high blood pressure]]>, can lead to damage to tiny blood vessels in the retina of the eye. This damage, called diabetic retinopathy, can occur over a long period of time. ]]>Cataract]]> and ]]>glaucoma]]> (two other common eye conditions) occur almost twice as often and at a younger age in people with type 2 diabetes than in people without this disease. Signs of eye damage include:

  • Blurry or double vision
  • Halos, flashing lights, or black spots
  • Dark or floating spots
  • Pain or pressure in one or both of your eyes
  • Trouble seeing things

A cataract is a cloud over the lens of your eye. Your lens, which is usually clear, focuses light onto the retina. A cataract makes your vision cloudy. Cataracts are removed with surgery. Glaucoma is a group of eye diseases caused by drainage problem of the fluid in the eye. Eventually there is damage to your eye's main nerve—the optic nerve. The damage first causes you to lose sight from the corners or sides of your eyes. Without treatment, you can go blind. Glaucoma can be treated with special eye drops or laser surgery.

Some people do not have any symptoms until the damage is significant. Therefore, it is essential to see your eye doctor regularly. Diabetic retinopathy can be treated with laser therapy or surgery. ]]>Quitting smoking]]> and controlling your blood pressure are important preventive measures. According to the National Eye Institute, 90% of blindness in people with diabetes is preventable.


Kidney Disease

Between 30%-40% of people with diabetes develop diabetic nephropathy (a form of kidney damage) after 20 years.

High blood glucose levels and high blood pressure damage the kidneys’ small blood vessels (capillaries). These capillaries are responsible for filtering waste out of the blood. This damage allows protein to leak out of the blood and causes wastes that should be excreted with the urine to build up in your blood. Having small amounts of protein in the urine is called microalbuminuria, the first sign of kidney damage.

As damage continues, more protein is leaked and more wastes build up. Having larger amounts of protein in the urine is called proteinuria or macroalbuminuria. This damage can eventually progress to kidney failure]]>, which requires ]]>dialysis]]> or a ]]>kidney transplant]]> .


Heart Disease

People with type 2 diabetes are more likely to have heart disease and to die from heart disease than people without diabetes. Microalbuminuria is a known risk factor for vascular disease, especially coronary artery disease]]>. Yearly urine screen for protein is recommended. In type 2 diabetes, high triglycerides and low HDL cholesterol levels are also quite common. These are known risk factors for heart disease.

Having diabetes can cause your cholesterol levels to rise, leading to clogged, narrowed arteries—a condition called ]]>atherosclerosis]]>. Clogged arteries make it more difficult for blood to carry oxygen and other essential nutrients to vital organs and tissues. The condition can also cause:

  • Chest pain ( ]]>angina]]> )—This pain or pressure typically starts in your chest and radiates to your arms (especially the left). This type of pain may appear when you exercise or after eating a large meal, and it may get better when you rest.
  • ]]>Heart attack]]> —This is caused by the blockage of a blood vessel in or near your heart. As a result, part of your heart muscle does not receive oxygen and the essential nutrients it needs to function, so it stops working and dies. Symptoms of a heart attack include: chest pain, pressure feeling, nausea, indigestion, extreme weakness, and sweating.
  • ]]>Cardiomyopathy]]>—This is a general weakening of the heart muscle caused by narrowed, small blood vessels that decrease the blood flow through the heart. This can progress and cause heart failure.



Type 2 diabetes makes you more likely to have a stroke]]> . A stroke is caused by a blockage of blood flow to the brain usually from emboli arising from the heart or carotid artery or due to a brain hemorrhage. The effects of a stroke depend on the part of your brain that is damaged, and may include:

  • Sudden weakness or numbness of your face, arm, or leg on one side of your body
  • Sudden confusion, trouble talking, or trouble understanding
  • Sudden dizziness, loss of balance, or trouble walking
  • Sudden trouble seeing in one or both eyes or sudden double vision
  • Sudden severe headache


Nerve Disease

Diabetes can also cause mild to severe nerve damage, called diabetic neuropathy]]>. Having high blood sugar for many years can damage the blood vessels that bring oxygen to the nerves. High blood sugar can also damage the covering on the nerves. Damaged nerves may stop sending messages. Or, they may send messages too slowly or at the wrong times. This can lead to symptoms that range from pain or tingling, to numbness and loss of feeling. The longest nerves in the body are often affected first, leaving the hands and feet most susceptible to neuropathy.

The combination of repeated injury, poor blood flow, and poor healing leads to a greater risk of foot infections that are often difficult to treat. In severe cases, when circulation is poor and antibiotics fail to cure the infection, foot and leg amputations may be necessary.

Other consequences of nerve damage may manifest as:

Foot Ulcers

Your feet are especially vulnerable to the complications of type 2 diabetes. Damage to the peripheral nerves—which go to the arms, hands, legs, and feet—can impair your experience of sensations (such as pain, heat, and cold). In addition to nerve damage, type 2 diabetes can also cause a decrease in blood flow. Therefore, if you have a blister or sore on your foot, you may not feel it because of the neuropathy. Because of the lack of sensation, this area on your foot may be continually re-injured. It is essential to wash and examine your feet daily. If your doctor recommends it, you may want to use an special skin thermometer to check the temperature of your feet. High foot temperature may be a sign of injury or inflammation.


Lower Your Chances of Complications

Take these steps to promote your health:

  • Have regular checkups even if you feel fine. Your doctor can often spot early signs of complications.
  • Strive to keep your blood glucose levels, hemoglobin A1c (HbA1c) levels, and blood pressure within a healthy range at all times. Work with your doctor to determine which levels that are safe for you.
  • Do not smoke. If you do smoke, quit.
  • Get vaccinated against the flu]]> and ]]>pneumonia]]>.
  • Exercise regularly (eg, aerobic exercise 3-5 times a week for 20-60 minutes each time).
  • Keep a close to normal weight.
  • Tell your doctor if you have any of these warning signs:
    • Vision problems, such as blurriness or spots
    • Tiredness
    • Pale skin color
    • Numbness or tingling feelings in hands or feet
    • Repeated infections or slow healing of wounds
    • Chest pain
    • Vaginal itching
    • Constant headaches
    • Cuts or blisters on your feet
  • Ask your doctor if there are any medicines that you should take to prevent complications

Intensive Therapy

For many years, patients and doctors have asked: Does tightly controlling blood glucose levels, to near normal levels, make a difference in long-term outcomes?

Researchers have found that patients who were able to intensively control their glucose levels (target: average HbA1c about 7%) had fewer eye, kidney, and neurological complications. Studies also suggest that controlling blood glucose will help reduce the rate of heart attack and stroke. Other studies, though, found that intensive treatment goals (HbA1c < 6.5%) using the medicines ]]>rosiglitazone]]> or ]]>gliclazide]]> may potentially increase harm.

Intensive control may not be right for everyone. To follow this treatment approach, you would need to monitor yourself more closely, be willing or able to use insulin, and learn self-management techniques. Intensive therapy may also increase your risk of hypoglycemia. Talk to your doctor about whether this approach is right for you.


ACE Inhibitors

ACE inhibitors are the name of a class of medicines that are generally used to treat high blood pressure and heart failure. These medicines work by blocking angiotensin-converting enzyme. This is a protein that helps the body make angiotensin, which in turn raises blood pressure. Thus, by blocking this enzyme the drug works to lower blood pressure.

This class of drugs is of particular interest for people with diabetes. There is evidence that these drugs have beneficial effects in patients with diabetes, in addition to lowering blood pressure. A clinical trial called HOPE (Heart Outcomes Prevention Evaluation) studied the effect of an ACE inhibitor, ]]>ramipril]]> (Altace) on patients who were at risk for heart disease. A subgroup of these patients also had diabetes.

The bottom line is: the study showed that an ACE inhibitor could reduce the frequency of heart attacks, stroke, and overall death rate in patients at high-risk for cardiovascular events. There is also strong evidence that ACE inhibitors slow the progression of kidney disease in patients with diabetes.

In a trial, researchers found that patients who took ramipril plus ]]>telmisartan]]>, a medicine to lower high blood pressure, did not have a reduction in mortality or the progression of cardiovascular disease (heart attack, stroke, ]]>peripheral artery disease]]>).

Talk to your doctor about whether ACE inhibitors are right for you.

Lipid-lowering Therapy

The American Diabetes Association (ADA) offers these guidelines on LDL "bad" cholesterol and coronary heart disease:

  • Make lifestyle changes to lower your LDL cholesterol levels. Reduce the amount of saturated fat and cholesterol in your diet. If you are overweight, lose weight. Increase how much physical activity you do each day.
  • If you do not have cardiovascular heart disease:
    • The goal is to have LDL cholesterol level less than 100 mg/dl.
    • If you are over age 40 years old and have at least one other risk factor for heart disease, treatment goal is a 30%-40% reduction of LDL regardless of baseline LDL levels.
    • If you are younger than 40 years old with other risk factors for heart disease and lifestyle changes fail to achieve the desired lipid-lowering goals, the ADA recommends medicine.
  • If you have cardiovascular heart disease:
    • The ADA recommends statins to reduce LDL 30%-40% from original values.
    • Lowering LDL cholesterol to below 70 using a higher dose of a statin is an option.
  • Lower triglycerides to less than 150 mg/dl and raising HDL cholesterol to over 40 mg/dl in men and over 50 mg/dl in women are other ADA treatment goals.

The American Heart Association (AHA) offers these recommendations on ]]>omega-3 fatty acids]]>:

  • All adults should eat fish at least twice weekly.
  • If you have coronary heart disease, you should receive at least 1 gram of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) combined every day.
  • EPA plus DHA supplement (eg, 2-4 grams) is useful in lowering triglyceride levels by 20%-40%.

One study also found that lowering lipid levels prevented the development of heart disease in patients with diabetes. Talk to your doctor about whether lipid lowering medicines are right for you.


People with diabetes are at increased risk of getting cardiovascular disease. Taking ]]>aspirin]]> may help decrease the risk of getting a heart attack in patients who are at risk for heart disease. Aspirin should be considered for patients who have had a heart attack. Talk to your doctor about whether the benefits of daily aspirin outweigh the risks in your case. Aspirin can cause bleeding and interacts with other drugs. It has not been studied in people younger than 30 years old with diabetes.