Diabetes complications can be divided into two types: acute (sudden) and chronic (long-term). This article discusses these complications and strategies to prevent the complications from occurring in the first place.

Acute complications

  • Diabetic ketoacidosis (DKA)
  • Hyperglycemic hyperosmolar non-ketotic syndrome (HHNS)

Acute complications of diabetes can occur at any time in the course of the disease.

Chronic complications

  • Cardiovascular: Heart disease, peripheral vascular disease, stroke
  • Eye: Diabetic retinopathy, cataracts, glaucoma
  • Nerve damage: Neuropathy
  • Kidney damage: Nephropathy

Chronic complications are responsible for most illness and death associated with diabetes. Chronic complications usually appear after several years of elevated blood sugars (hyperglycemia). Since patients with Type 2 diabetes may have elevated blood sugars for several years before being diagnosed, these patients may have signs of complications at the time of diagnosis.

Basic principles of prevention of diabetes complications:

  • Take your medications (pills and/or insulin) as prescribed by your doctor.
  • Monitor your blood sugars closely.
  • Follow a sensible diet. Do not skip meals.
  • Exercise regularly.
  • See your doctor regularly to monitor for complications.

Diabetic ketoacidosis (DKA)

  • Results from untreated hyperglycemia.
  • Blood sugars typically range from 300 to 600.
  • Occurs mostly in patients with Type 1 diabetes (uncommon in Type 2).
  • Occurs due to a lack of insulin.
  • Body breaks down its own fat for energy, and ketones appear in the urine and blood.
  • Develops over several hours.
  • Can cause coma and even death.
  • Typically requires hospitalization.

Symptoms of DKA

  • Nausea, vomiting
  • Abdominal pain
  • Drowsiness, lethargy (fatigue)
  • Deep, rapid breathing
  • Increased thirst
  • Fruity-smelling breath
  • Dehydration

Causes of DKA

  • Inadequate insulin administration (not getting enough insulin)
  • Infection
  • Myocardial infarction (heart attack)

Prevention of DKA

  • Take your medications as prescribed.
  • Monitor your blood sugar closely, especially when you are ill.
  • Keep a balanced diet with regularly scheduled meals.
  • Keep yourself well-hydrated (get plenty of fluids).
  • Exercise regularly.
  • Call or see your doctor if you or family members notice symptoms of DKA, and/or your blood sugar is elevated (above 300).

Hyperglycemic hyperosmolar non-ketotic syndrome (HHNS)

  • More gradual onset (develops more slowly) than DKA (days to even weeks).
  • Occurs in patients with type 2 diabetes, especially the elderly.
  • Usually occurs when patients are ill or stressed.
  • Blood sugars typically are greater than 600.
  • Symptoms include frequent urination, drowsiness, lethargy, and decreased intake of fluids. HHNS is not typically associated with nausea, vomiting, or abdominal pain.
  • Not associated with ketones in the blood.
  • Can cause coma or death.
  • Typically requires hospitalization.

Prevention of HHNS

  • Similar to DKA.
  • Take your medications as prescribed by your doctor.
  • Monitor your blood sugars carefully, especially when you are ill.
  • Keep yourself well-hydrated.
  • Call or see your doctor if you, or a family member, think you may have symptoms of HHNS and/or your blood sugars are elevated.

Cardiovascular complications in diabetes

  • Cardiovascular disease is the most deadly complication of diabetes.
  • 75 to 85% of patients with diabetes die from heart disease or stroke.
  • Diabetes is one of the leading risk factors for cardiovascular disease.
  • Patients with diabetes have the same risk for cardiovascular disease as patients without diabetes who have had an earlier cardiovascular event.
  • Men with diabetes are two to three times more likely to develop cardiovascular disease than are men without diabetes.
  • Women with diabetes are four to six times more likely to develop cardiovascular disease than are women without diabetes.
  • Patients with diabetes often do not have the classic symptoms of heart disease, such as chest pain.

Risk factors for heart disease

  • Age
  • Diabetes
  • High blood pressure
  • High cholesterol
  • Tobacco use
  • Family history of heart disease

General principles for prevention of heart disease in patients with diabetes

  • Aggressive control of blood sugar.
  • Aggressively treat other modifiable risk factors for heart disease (high blood pressure, high cholesterol, and smoking).
  • Aspirin has been shown to be protective in patients with known cardiovascular disease. Although it has not definitively been shown to prevent heart disease, it should be considered in patients with diabetes, especially those with other risks for heart disease (high blood pressure, high cholesterol). Ask your doctor if aspirin is appropriate for you.
  • There are no specific recommendations about routine stress testing to look for heart disease in patients with diabetes. Ask your physician if he or she thinks you need a stress test.

Peripheral vascular disease

  • Decreased blood flow in the legs and feet.
  • Symptoms: Pain in the calf, thigh, and buttocks while walking. Symptoms are relieved with rest. These symptoms are known as intermittent claudication.
  • Claudication is associated with an increased risk of heart disease, leg ulcers/infections, and lower extremity (leg) amputation.
  • If you think you have symptoms of claudication, please tell your doctor.

Cholesterol and diabetes

Patients with diabetes should have a fasting cholesterol profile check at least every year.

  • Component: Total cholesterol; goal for patients with diabetes: < 200
  • Component: LDL cholesterol (bad cholesterol); goal for patients with diabetes: < 100; < 70 for those with diabetes and heart disease
  • Component: HDL cholesterol (good cholesterol); goal for patients with diabetes: men: above 45; women: above 55
  • Component: Triglycerides (fats in the blood); goal for patients with diabetes: < 150

The typical cholesterol profile in patients with diabetes includes low HDL cholesterol and high triglycerides.

The focus of treatment of high cholesterol in patients with diabetes is to lower the LDL cholesterol. Studies show that the risk for cardiovascular disease in patients with diabetes may increase if LDL cholesterol is above 80.

Treatment of high cholesterol in patients with diabetes

  • Control blood sugars, blood pressure
  • Low-fat diet
  • Quitting smoking
  • Exercise and weight loss can help raise the HDL cholesterol
  • Medications


Statin drugs (HMG CoA reductase inhibitors)

Examples: Lipitor®, Zocor®, Pravachol®, Crestor®, Mevacor®, Lescol®

Statin drugs are the most powerful drugs that we have to lower LDL cholesterol. These medications are especially effective at lowering LDL and total cholesterol. They can also help lower triglycerides and raise HDL cholesterol.

Two rare but potential side effects of statins are liver inflammation (swelling) and muscle damage. Symptoms of liver inflammation include nausea, vomiting, pain on the right side of the abdomen, decreased appetite, dark-colored urine, and light-colored stools. Symptoms of muscle damage include any new muscle soreness or weakness. If you think you have developed any of these symptoms while on statin drugs, please tell your doctor immediately.


Tricor®, Lopid®

The main effect of fibrates is to lower triglycerides. They also can lower LDL cholesterol and raise HDL cholesterol. These medications can also cause liver inflammation.


Niacin lowers triglycerides and LDL cholesterol while raising HDL cholesterol. Niacin can make diabetes more difficult to control, but this does not mean that you cannot be started on this medication. Niacin can also cause liver inflammation.

ACE inhibitors

One study showed that the ACE inhibitor Ramipril® (a blood pressure medication) decreased the rate of heart attack, stroke, and death from cardiovascular causes in patients with diabetes, a cholesterol above 200, or a low HDL cholesterol. These medications are not suitable for all patients, so please consult your doctor.

Eye complications with diabetes

  • Diabetes is the leading cause of new blindness in adults ages 20 to 74.
  • Patients with diabetes are 25 times more likely to become legally blind than are patients without diabetes.
  • There are three eye-related major complications: retinopathy, cataracts, and glaucoma.
  • Blurred vision can occur as a result of high blood sugars. However, it can also be a result of more serious eye problems. Contact your doctor if your vision is blurred.

Prevention of eye complications

  • Visit your ophthalmologist (eye doctor) at least once a year for a comprehensive eye exam to screen for retinopathy, cataracts, and glaucoma.
  • Maintain intensive control of blood sugars.
  • Control your blood pressure.

Diabetic retinopathy

  • Damage to the retina (the lining of the inside of the eye)
  • Patients with type 2 diabetes may have signs of retinopathy when they are diagnosed with diabetes.
  • Two types: non-proliferative and proliferative
  • Non-proliferative: Common and usually mild. Typically occurs after several years of diabetes. Patients do not typically have symptoms with this form of retinopathy.
  • Proliferative: New blood vessels grow in and around the retina. Symptoms include blurred vision, black spots or holes in the vision, and blindness. Treatments include laser therapy and surgery. Some patients with the non-proliferative form of retinopathy progress to the proliferative form.


  • Clouding or fogging of the lens
  • Symptoms: blurred or cloudy vision
  • Treatment: surgery, lens implants


  • Increased pressure in the eyes
  • Symptoms: headache, nausea, vomiting, eye pain, decreased vision, blurred vision, watering of the eyes
  • Treatment: eye drops, laser therapy, surgery

Neuropathy (nerve damage) and diabetes

  • Two forms: peripheral and autonomic
  • 50 to 70% of patients with diabetes develop neuropathy.
  • Neuropathy most likely develops due to long-term high blood sugars.
  • Diabetes is the leading cause of non-traumatic lower limb amputation.

Peripheral neuropathy

  • Affects sensation (feeling), especially in legs and feet.
  • Can be permanent.
  • Symptoms: burning, pain, tingling, or numbness in the extremities, especially in the feet and legs
  • Symptoms are usually noticed at rest, and are often worse at night.
  • Sometimes does not cause symptoms.
  • Medications to help relieve symptoms: tricyclic antidepressants Elavil®, Neurontin®, Topamax®, Lyrica®.

Peripheral neuropathy is potentially serious. Since patients with diabetes have a decreased ability to perceive pain, they may not notice minor and even major injuries or trauma. Similarly, because of difficulty perceiving changes in position, patients with diabetes may have problems bearing weight properly, which puts them at risk for developing calluses and ulcers on their feet.

Prevention of diabetes complications involving the feet and legs

  • Control blood sugars.
  • Keep your feet clean and moist.
  • Wear properly fitting shoes and clean socks. Do not walk barefoot.
  • Take warm (not hot) showers.
  • Examine your feet every day for evidence of skin breakdown, sores, or ulcers.
  • See your doctor for any foot injury or ulcer. Do not try to treat them yourself.
  • See a podiatrist (foot doctor) for foot and nail care.

Autonomic neuropathy


  • Symptoms: Low blood pressure, fast pulse, dizziness, passing out
  • Treatment: Avoid standing up too quickly, medications, stockings.


  • Symptoms: Nausea, vomiting, decreased appetite, feeling full more quickly, bloating, diarrhea, constipation
  • Treatment: Control of blood sugar, smaller meals, medications


  • Symptoms: Impotence, female sexual dysfunction, unable to empty bladder fully
  • Treatment: Erectile dysfunction medications (for example, Viagra®), vaginal lubricants, self-catheterization
  • Skin: Dry, cracked skin, impaired wound healing

Nephropathy (kidney damage) and diabetes

  • Diabetes is the leading cause of end-stage kidney disease in the United States.
  • End-stage kidney disease requires dialysis and/or a kidney transplant.
  • An early sign of kidney damage with diabetes is the presence of small amounts of protein (albumin) in the urine.
  • If protein in the urine is not diagnosed or treated, it can lead to end-stage kidney disease.

Prevention of kidney damage in patients with diabetes

  • Visit your doctor at least once a year for blood tests (BUN and creatinine) to measure your kidney function. Your doctor should also check your urine once a year for protein.
  • Maintain strict control of blood sugars and blood pressure.
  • ACE inhibitors and angiotensin II receptor blockers (ARBs) (blood pressure medications) have been shown to slow down kidney disease in patients with diabetes. Commonly prescribed ACE inhibitors include Altace®, Accupril®, Zestril®, and Vasotec®. Commonly prescribed ARBs include Diovan®, Cozaar®, and Avapro®.
  • Monitor the amount of protein in your diet. Patients with signs of protein in the urine should cut down modestly on protein. You may want to consult a nutritionist or diabetes educator to determine how much protein you should have in your diet.

Last reviewed by a Cleveland Clinic medical professional on 03/29/2017.


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