The complications of diabetes

There are many complications of diabetes which can be very severe in some cases.
These complications can worsen your diabetes and reduce your life expectancy.
Most diabetic complications can be avoided, reduced or delayed if diabetes is detected and treated early and correctly.

Long-term Complications


  • 1 million deaths worldwide
  • Eye disorders:
    • Diabetes is the commonest cause of retinopathy
    • 10% reported a decrease in visual acuity
    • 2% of diabetics are blind
  • Commonest cause of kidney failure:
    • 10% of dialysis patients have severe kidney disease due to diabetes
  • 75% of diabetics die from complications of atherosclerosis:
    • Patients suffer with angina, heart attacks, stroke and reduced blood flow to lower limbs
    • 10 to 15% of heart attacks occur in diabetics
  • Amputation :
    • 1 million amputees in the world
    • Diabetes is the commonest cause of amputation
    • 5 to 10% of diabetics are or will be amputated of a toe, a foot or a leg.
    • The risk of gangrene is multiplied by 7 if you have diabetes


Diabetes is one of the major risk factors for cardiovascular disease and thereby increases the risk of cardiovascular events and stroke.
This is caused by "hardening of the arteries" when cholesterol deposits in the major blood vessels.

Microvascular problems

In diabetes, small vessels and capillaries are also often damaged . This then causes eye, kidney and nerve problems.

Diabetic retinopathy

Diabetic retinopathy, retinal eye disease, is a major complication of diabetes, making it the leading cause of blindness in the Western world:
  • 2% of diabetics go blind.
  • 10% of people with diabetes have vision problems .
  • In most patients, eye disease occurs when diabetes has been present over 15 years, but initial changes can be difficult to notice.
  • A normal visual acuity does not eliminate the diagnosis of retinopathy.
  • Treatment of diabetic retinopathy :
    • Controlling diabetes and blood pressure is a necessity
    • Laser photocoagulation is performed in advanced retinopathy using a device that sends light rays to destroy lesions and hence heal the retina.
  • If you are diabetic, you will be entitled to free yearly checks to check for any signs of retinopathy. Please discuss this with your optician or GP to ensure you are enrolled into this national programme.

Diabetic nephropathy

  • Blood vessels in the kidneys can get also be affected causing kidney disease, or even renal failure (when your kidneys.
  • The first sign of kidney damage is the presence of protein in urine. This is why your GP or specialist will always analyse your urine to screen for protein, even though you may be asymptomatic.
  • If there is protein in your urine, you may be referred to a kidney specialist for additional treatment to protect your kidneys from further damage.
  • 50% of insulin dependent diabetics are suffering from chronic renal failure.

Diabetic neuropathy

  • Diabetic neuropathy affects 50% of patients who have suffered with diabetes for over 20 years
  • It affects 50% of diabetics over the age of 65 due to nerve damage and poor circulation
  • Diabetic neuropathy may affect a single nerve or more commonly, the peripheries.
  • For example, if the oculomotor nerve is affected alone, you may experience diplopia (double vision)
  • Peripheral neuropathy usually affects the legs and causes:
    • Decreased pain sensation so you do not feel injuries such as bumps or torn fingernails
    • Decreased sensitivity to heat
    • Dry skin causing cracks that can become infected
    • Deformities of the foot including calluses
  • Diabetic neuropathy can also affect the autonomic nervous system and cause :

Recurrent Infections

  • Diabetics are predisposed fungal and bacterial infections as well as urinary tract infections and skin infections
  • These infections can make it difficult to control your blood sugar

Complications involving blood sugar control


This occurs if your blood sugar is too low - please see the chapter "Hypoglycaemia" under diabetes on this website for more information


  • If you eat too many sugary foods or do not follow your treatment plan correctly, you can develop an excess of sugar in your blood .
  • Stress, anxiety or lack of physical exercise can also have an impact and cause high blood sugar levels.
  • Signs are sometimes difficult to spot but include thirst, hunger, fatigue and frequently needing to urinate.
  • Your doctor and/or specialist can advise you how to avoid this and optimise your medication and blood sugar control tailored to your individual lifestyle.

Diabetic Ketoacidosis (DKA)

Ketoacidosis is a life-threatening condition in diabetics.
  • DKA usually occurs in type I diabetics or during an intercurrent illness when there no little or no insulin in the body to reduce blood sugar.
  • Hence, blood sugar levels are extremely high, sugar levels in your urine also increase, and you become incredibly dehydrated and develop ketones.
  • The body produces ketones when your body is very stressed and severely dehydrated and starts to break down its own fat as it. Ketones are most easily detected in the urine using urine test strips.
  • Your blood then turns very acidic and this can be fatal.
  • DKA is an emergency as you will need large amounts intravenous fluids and insulin very quickly, and also the cause of DKA will need to be ascertained and treated (for example, antibiotics for an infection).
  • Ketoacidosis can present with:
    • Increased thirst and urination
    • Weight loss
    • Tiredness
    • Dehydration
    • Abdominal pain, nausea and/or vomiting
    • Shortness of breath
    • Weakness, drowsiness and coma if severe

If you or your family suspect DKA, you must call an ambulance immediately
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