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Long-Term Complications of Diabetes: Causes, Symptoms, and Prevention

Written by: Content Team



Time to read 9 min

While diabetes itself might have minor symptoms, the long-term complications of diabetes associated with it can significantly affect your quality of life. That's why learning about the outlook for this disease is so important.

Let's get into the complications of diabetes and how you can reduce some of these risks to maintain a high quality of life.

How Does Diabetes Lead to Complications?

Diabetes is caused by chronic hyperglycemia, i.e., when there has been too much sugar in your blood for too long. This then increases your risk of getting complications in four ways:

  • Cells change sugar (glucose) into a substance called sorbitol and then into another substance called fructose. This change uses up a protective substance named NADPH. Without enough NADPH, cells are more easily damaged by harmful molecules called free radicals.
  • It leads to more production of harmful substances known as advanced glycation end products (AGEs). These change the way cells communicate and function, leading to several problems. They also cause more inflammatory cells to form, harming blood vessels.
  • It can also alter DNA, turning off genes that are important for cells to work properly. For example, it can increase the production of substances that narrow blood vessels, leading to diseases related to blood vessels.
  • It increases the production of a harmful molecule called superoxide. This breaks down into hydrogen peroxide, which can also damage blood vessels.

This can narrow blood vessels, limiting your blood's ability to travel where needed. This means your organs won't work properly, which can cause various effects depending on which organ system is affected.

What Are the Long-Term Complications of Diabetes?

Common long-term complications of diabetes are broadly classified as microvascular or macrovascular. Let's look at them below.

Macrovascular Complications

Macrovascular complications affect large blood vessels, which cause the development of the following diseases.

Coronary Heart Disease

Middle aged man having heart attack in his office
Middle aged man having heart attack in his office. Source: DepositPhotos

Diabetes and heart health are closely related. Coronary heart disease (CHD) occurs when blood vessels can't deliver oxygen-rich blood to your heart. It is a result of the buildup of fatty deposits on the walls of the arteries of the heart, which causes them to become narrower and carry less blood.

Since this cardiovascular disease develops over decades, most symptoms go unnoticed until a cardiac event happens. However, certain symptoms hint at this disease, such as:

  • Shortness of breath
  • Chest pain
  • Sharp pain in the arm, back, or neck
  • Fatigue (when exercising or performing any activity)
  • Heart attack (this happens when the heart arteries are completely blocked)

People with diabetes have a four times higher risk of developing CHD than those without diabetes.

Cerebrovascular Disease

Cerebrovascular disease happens when blood flow to the brain is reduced. This is caused when the carotid or vertebral arteries narrow, get blocked, or rupture. This condition can have the following symptoms:

  • Sudden, severe headache
  • Fainting
  • Balance issues
  • Loss of vision
  • Double vision
  • Weakness or paralysis on one side of your body or face
  • Trouble speaking
  • Slurred speech

Peripheral Limb Disease

Peripheral limb disease, such as peripheral vascular disease (PVD) or peripheral arterial disease (PAD), is a circulatory disorder that reduces blood flow through the arteries in the feet, calf, or thighs.

Most patients don't experience any symptoms. However, they may first experience leg cramping, discomfort, or pain that occurs with exercise and goes away with rest. Other symptoms include:

  • Redness on the skin of the legs
  • Cool skin on the feet
  • Foot or toe sores that don't heal
  • Burning pain in toes or feet when lying flat
  • Frequent foot or leg infections

As this condition progresses, patients can develop dead tissue in the legs, which may require amputation.

Fortunately, this condition is preventable. Medications that treat diabetes and lifestyle changes, like exercising and eating a balanced diet, can help reduce your risk of getting PAD or PVD.

Microvascular Complications

Microvascular complications affect the capillaries, which are small-sized blood vessels. They're more common than macrovascular complications and cause the development of the following diseases.

Diabetic Nephropathy

Man suffering from pain in back or kidneys sitting on bench on street
Man suffering from pain in back or kidneys sitting on bench on street. Source: DepositPhotos

Diabetic nephropathy — also called chronic kidney disease — happens when uncontrolled diabetes causes blood vessel damage in the kidneys, reducing their ability to filter waste. It typically occurs ten to 15 years after a diabetes diagnosis.

Kidney disease doesn't always have visible symptoms, especially during the early stages. 

However, you may notice:

  • Blood in urine
  • Extreme fatigue
  • Shortness of breath
  • Feeling sick
  • Swollen hands, ankles, and feet

If you develop the disease, you can slow its progression by managing your diabetes well.

Diabetic Retinopathy

Diabetic retinopathy occurs when high blood sugar levels damage the blood vessels in the back of the eye (retina). This disorder can cause the following symptoms:

  • Seeing floaters (spots) or flashes
  • Trouble seeing colors
  • Difficulty reading
  • Dark or empty areas in your vision
  • Blurry vision
  • Vision loss

Fortunately, multiple diabetic retinopathy treatments can help repair eye damage and prevent blindness. These include retinal detachment, vitrectomy, laser surgery, and corticosteroid injections.

Diabetic Neuropathy

Diabetic neuropathy is nerve damage that happens when long-term high blood sugar levels cause damage to your nerves. It has several types:

  • Peripheral neuropathy: This affects the legs and feet. Its symptoms include a burning sensation, numbness, or pain.
  • Autonomic neuropathy: It affects the circulatory, digestive, and urinary systems. Symptoms include blacking out when standing up quickly, feeling full after small meals, bloating, diarrhea, low blood pressure, and incontinence.
  • Focal neuropathy: It causes sudden pain or weakness in specific nerves in the legs, torso, or head. Some of its symptoms include eye pain, double vision, and severe pain in the lower extremities.

Unfortunately, there is no known cure to stop this disease from progressing. This is why treatment mainly focuses on slowing progression, restoring function, and relieving pain/other complications.

Diabetic Foot

The feet of people with diabetes, dull and swollen. Due to the toxicity of diabetes placed on a white background. Fingers hit the back of the diabetic foot. To test foot swelling.
The feet of people with diabetes, dull and swollen. Due to the toxicity of diabetes placed on a white background. Fingers hit the back of the diabetic foot To test foot swelling.. Source: DepositPhotos

Diabetic foot is caused by consistently high blood sugar levels that damage the blood vessels in the calves and feet. This reduces blood circulation and prevents cells from receiving oxygen-rich blood and nutrients, causing them to develop gangrene (dead tissue) that has to be amputated.

However, this happens gradually and may cause you to experience the following symptoms before gangrene kicks in:

  • Reduced ability to feel cold, heat, or pain
  • Numbness or tingling in the toes or feet
  • Pain or cramping in the calves, thighs, or buttocks during physical activity
  • Dry, cracked skin on the feet
  • Frequent fungal infections between the toes

There is no way to reverse blood vessel damage once it happens. But you can take precautions to reduce the chances of it occurring. This means keeping your blood sugar levels in check and taking good care of your feet.

Other Complications

Some diabetic complications aren't caused by blood vessel damage, so they aren't classified as micro- or macrovascular complications. Let's look at five of them below.

Necrobiosis Lipoidica

Necrobiosis lipoidica is a rare skin condition that causes patches of the skin to develop into ulcers. It usually affects the calves or ankles of people with diabetes.

This disorder begins as smooth red-brown bumps on the lower legs that progress into shiny, flat yellow-brown patches. These patches may develop itchy and painful ulcers if exposed to trauma.

They're also challenging to treat. However, laser therapy, corticosteroid injections, creams, and anti-inflammatory drugs can help if the patches haven't developed into ulcers. If they have, surgery may be required to treat them.


Mucormycosis is an aggressive, life-threatening fungal infection that often affects diabetic patients because they're immunocompromised. It is caused by molds that enter the skin at a trauma site, such as a cut or a burn.

The infection causes the following symptoms:

  • Headaches
  • Swelling
  • Redness
  • Fever
  • Ulcers
  • Blackened skin tissue

Mucormycosis can be fatal if not treated quickly. Once the diagnosis has been confirmed, several antifungal drugs are used to treat it. However, if the tissue has turned necrotic, surgical debridement (where necrotic tissue is removed using a scalpel) is required.

Diabetic Cardiomyopathy

Diabetic cardiomyopathy is a disorder in which high blood sugar levels change the structure of the myocardium (heart muscle), causing it to become thick or stiff. It prevents your heart from pumping enough oxygen-rich blood to meet the needs of your cells. This leads to:

  • Chest discomfort
  • Fatigue
  • Breathlessness at rest
  • Swollen feet, ankles, and legs
  • Increased inflammation
  • Bloating

There is no cure for diabetic cardiomyopathy because it causes permanent changes in the heart tissue. It's managed by treating individual symptoms, such as swelling or shortness of breath.

Diabetic Fatty Liver Disease

Diabetic fatty liver disease occurs when too much fat builds up in the liver due to high sugar consumption and low physical activity. It leads to:

  • Shortness of breath
  • Abdominal swelling
  • Enlarged spleen
  • Jaundice (yellowing of the skin)
  • Leg swelling

The fastest way to treat diabetic fatty liver disease is by limiting high-calorie food consumption, increasing physical activity, and losing weight.

Limited Joint Mobility Syndrome (Also Known as Diabetic Cheiroarthropathy)

Limited joint mobility syndrome (LJMS) is a disorder that reduces joint mobility and strength in the hands and feet of diabetic patients. As the disease progresses, it can also cause the impairment of other joints, such as the hip, spine, or shoulder.

It has the following symptoms:

  • Limited fine motion
  • Impaired grip strength
  • Joint stiffness and pain

LJMS is an irreversible disorder, so treatment focuses on slowing its progression and maintaining function through symptomatic therapy, daily exercise, or surgery.

How to Prevent the Long-Term Complications Associated With Diabetes

Diabetes might be unpreventable due to the genetic component involved in its development. However, the long-term complications associated with it are definitely preventable. Let's understand how you can do that.

1. Ensure Good Sugar Control

Uncontrolled diabetes is the main cause of most long-term complications associated with the disease. This means controlling your sugar is the first step to take when looking to put a stop to diabetes-associated complications.

You can do this in several ways:

  • Get your glycosylated hemoglobin (HbA1C) levels checked twice a year.
  • Monitor your fasting blood glucose levels. They should be between 70 mg/dL and 100 mg/dL. Consider non-invasive glucose monitoring for a pain-free experience.
  • Reduce carbohydrate consumption and eat high-fiber foods.

2. Get Regular Medical Checkups

Getting annual medical checkups can help you catch diseases before they become problems. For instance, if you get regular eye assessments, you can catch the development of diabetic retinopathy early on in the disease.

Here are the recommended frequencies and intervals for different screening tests among people with diabetics:

3. Lower Your Cholesterol and Blood Pressure

Your blood pressure and cholesterol can combine with high blood sugar to cause metabolic syndrome, which worsens diabetes complications. For instance, a diet high in low-density lipoproteins (LDL) can increase arterial plaque and the risk of heart attacks.

Similarly, high blood pressure can damage the walls of renal veins and arteries, increasing the risk of developing kidney disease. This means controlling your cholesterol and blood pressure levels is essential if you're looking to reduce long-term diabetes complications.

Here's how you can do that:

Ease Your Insulin Therapy with InsuJet

InsuJet injector kit
InsuJet injector kit: Source: Insujet

Diabetes self-management is complex, difficult, and hard to manage even if you follow the best diabetes management tips. And if you’re insulin-dependent, you’re all too familiar with the painful injections that often cause bruising, and in some cases may even lead to infections.

That's where InsuJet comes in.

Our needle-free injections make insulin therapy painless, easy, and manageable. If you're looking for a way to get your daily insulin dose and reduce your risk of long-term complications, shop for injectors with us today!

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