Chronic Complications of Diabetes Mellitus – Kaohsiung Armed Forces General Hospital
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Chronic Complications of Diabetes Mellitus

Date： 2026-06-01

Chronic Complications of Poorly Controlled Diabetes Mellitus

When blood glucose levels are poorly controlled over time, diabetes can progressively lead to the following complications:

I. Complications

(1) Macrovascular Complications

Damage to large blood vessels due to atherosclerosis can affect the brain, heart, and lower extremities.

  • In the brain and heart, atherosclerosis increases the risk of:
    • Hypertension (high blood pressure)
    • Stroke
    • Myocardial infarction (heart attack)
  • In the feet and lower limbs, reduced blood supply may cause:
    • Coldness of the feet
    • Decreased sensation
    • Increased risk of wounds and ulcers

Because wound healing is slower in people with diabetes, infections characterized by redness, swelling, warmth, and pain may develop and, in severe cases, lead to amputation.

(2) Eye Complications

Diabetes is a leading cause of blindness.

It may result in:

  • Cataracts
  • Glaucoma
  • Macular edema
  • Diabetic retinopathy and other retinal disorders

(3) Diabetic Neuropathy

Diabetes can damage the nerves and cause neuropathy.

Symptoms may include:

  • Abdominal bloating
  • Constipation
  • Diarrhea
  • Palpitations (awareness of a rapid or pounding heartbeat)
  • Urinary or fecal incontinence
  • Difficulty urinating
  • Sexual dysfunction
  • Numbness and tingling of the hands and feet
  • Reduced sensation

(4) Diabetic Nephropathy (Kidney Disease)

Diabetes may damage the kidneys and cause:

  • Edema (swelling)
  • Foamy urine (proteinuria)

In severe cases, kidney function may deteriorate significantly, leading to:

  • Uremia (kidney failure)
  • The need for long-term dialysis to maintain kidney function

II. Prevention

(1) Maintain Good Control of Blood Glucose, Blood Pressure, and Blood Lipids

A. Blood Glucose Control

  • People with diabetes should aim to keep their HbA1c (glycated hemoglobin) level below 7%.

B. Blood Pressure Control

  • Recommended target systolic blood pressure: 120–130 mmHg
  • Recommended target diastolic blood pressure: 70–80 mmHg

Maintaining stable blood glucose, blood pressure, and lipid levels can significantly reduce the risk of long-term diabetic complications and improve overall health outcomes.

(1) Maintain Good Control of Blood Glucose, Blood Pressure, and Blood Lipids

A. Blood Glucose Control

  • People with diabetes should aim to keep their HbA1c (glycated hemoglobin) level below 7%.

B. Blood Pressure Control

  • Recommended target systolic blood pressure (SBP): 120–130 mmHg
  • Recommended target diastolic blood pressure (DBP): 70–80 mmHg

For diabetic patients 65 years of age and older, current guidelines suggest that maintaining a systolic blood pressure between 130–139 mmHg is generally acceptable.

C. Blood Lipid Control

Low-density lipoprotein cholesterol (LDL-C) targets:

  • General diabetic patients:
    • LDL-C < 130 mg/dL
  • Patients with moderate cardiovascular risk:
    • LDL-C < 100 mg/dL
  • Patients with high cardiovascular risk:
    • LDL-C < 70 mg/dL
  • Patients with very high cardiovascular risk:
    • LDL-C < 55 mg/dL

(2) Annual Retinal Examination

  • Undergo a dilated retinal (fundus) examination at least once a year to detect diabetic eye disease early.

(3) Annual Peripheral Vascular and Neurological Assessments

  • Have a peripheral vascular examination and a peripheral neuropathy assessment at least once annually.

(4) Perform Regular Foot Exercises and Foot Care

  • Engage in foot exercises to promote circulation.
  • Take precautions to prevent foot injuries, cuts, burns, and pressure sores.

(5) Exercise Regularly and Maintain a Healthy Weight

  • Participate in regular physical activity.
  • Maintain a healthy body weight.

Recommended Body Mass Index (BMI):

  • 18.5–24 kg/m²

(6) Stop Smoking

  • Smoking cessation is strongly recommended, as smoking increases the risk of vascular complications and impairs circulation.

(7) Improve Microvascular Circulation to the Nerves

  • Follow medical recommendations and lifestyle measures that help improve blood flow to the nerves and reduce the progression of diabetic neuropathy.

(8) Promptly Treat Urinary Tract Infections

  • Seek timely treatment for urinary tract infections (UTIs) to prevent complications and preserve urinary tract health.

Key Strategies to Prevent Diabetic Complications

  1. Keep HbA1c below 7%.
  2. Maintain target blood pressure and cholesterol levels.
  3. Receive annual eye examinations.
  4. Undergo yearly vascular and nerve assessments.
  5. Practice proper foot care and avoid injuries.
  6. Exercise regularly and maintain a healthy BMI.
  7. Quit smoking.
  8. Improve nerve circulation and manage neuropathy.
  9. Treat urinary tract infections promptly.

These measures can significantly reduce the risk of diabetic complications affecting the eyes, kidneys, nerves, heart, brain, and lower extremities.