When glucose levels in the blood, often known as blood sugar, are too high, you are at risk for developing a disease known as diabetes. Diabetes mellitus, a metabolic disorder, is characterised by improper glucose metabolism. Since diabetes is a long-term condition, it can lead to several complications of diabetes mellitus over time.

Most complications of diabetes are caused by the progression of the disease and the damage to the target organs. These diabetic consequences make their appearance over time as the condition worsens. Diabetes-related problems are far less likely to develop in those who follow a diet plan and medications, exercise consistently, and monitor their blood sugar levels.

Complications of Diabetes

The complications of diabetes can be categorised into two types: acute and chronic.

Acute Diabetic Complications

The two most serious acute complications are hyperglycemic hyperosmolar state (HHS) and diabetic ketoacidosis (DKA).

  1. Diabetic Ketoacidosis (DKA) 

It is a life-threatening consequence of type 1 diabetes and a medical emergency requiring immediate treatment. DKA is less prevalent during the diagnosis and treatment of type 2 diabetes.

Insufficient insulin prevents the body from adequately utilising sugar as a source of energy. It triggers the release of chemicals that decompose fat as fuel, leading to the production of acids called ketones. Toxic ketones are deposited in the bloodstream and excreted in the urine. As insulin levels are low in diabetes, ketone levels increase. It lowers the blood’s pH, leading to acidosis. The symptoms are as follows:

  • Dehydration
  • Rapid breathing
  • Extreme stomach pain
  • Lethargy which can lead to a coma if untreated
  • Low blood pressure
  • Shock

In extreme cases, shock or brain oedema can result in death. It can be identified with a urine test, revealing a substantial level of ketones. If appropriately treated, the patient can recover.

  1. Hyperglycemic Hyperosmolar State (HHS)

HHS occurs more often with type 2 than that with type 1 diabetes. It has comparable symptoms to DKA. It occurs in people with extremely high blood glucose (more than 300 mg/dL). HHS has ten times the mortality of DKA.

Stroke, heart attack, sepsis, pneumonia, and other serious infections usually precipitate HHS. In addition, hyperglycemia causes osmotic diuresis, making you lose water and intravascular volume.

An untreated condition can lead to severe complications like coma, resulting in death. Therefore, the initial treatment for this condition should consist of fluid volume replacement.

Chronic Diabetes Complications

Chronic complications may be vascular or nonvascular. Skin changes, infections, and gastroparesis are nonvascular complications of diabetes

Years of uncontrollably high blood sugar levels in people with diabetes result in several issues, most of which are vascular. It can affect small (microvascular), large (macrovascular), or both types of blood vessels. Chronic hyperglycemia is associated with microvascular complications.

A. Microvascular disease

Microangiopathy is a condition in which high blood glucose levels damage the small blood vessels. Three prevalent and severe complications are caused by microvascular disease:

  • Nephropathy: Small blood artery damage is a common consequence of diabetes. Since the kidney’s glomeruli are a collection of blood vessels, diabetes affects them; hence, the filtration mechanism is impaired. It causes serious kidney damage and can lead to end-stage kidney disease.
  • Neuropathy: In simple terms, neuropathy means damage to the nerves. The capillaries, the small blood vessels that supply blood to the nerves, are damaged by high glucose levels. When the nerves’ blood supply is interrupted, nerve injury occurs. These include tingling sensations in the legs, numbness, soreness or a burning sensation. In addition, there may be nausea, vomiting, diarrhoea, or constipation. Neuropathy causes diabetic amyotrophy or muscle weakening.
  • Retinopathy: Increased blood glucose can potentially harm the blood vessels of the retina. When an individual has diabetes, their blood sugar increases, making the lens less clear. This is called a cataract. Diabetes can cause blindness if it is not controlled.

B. Macrovascular disease

Diabetes elevates atherosclerosis risk and causes cardiovascular problems. Diabetes-related macrovascular consequences include coronary artery disease, peripheral artery disease, and cerebrovascular disease (CVD). Initial macrovascular disease is related to atherosclerotic plaques within the blood vessels of the brain, limb, and other organs. In the advanced stages, these blood channels become completely obstructed, which may raise the risk of strokes, claudication, and gangrene. CVD is the leading cause of death and disability in people with diabetes.

  • Cardiovascular complications: Diabetes mellitus can impact the cardiovascular system. Diabetes is a major risk for numerous heart diseases, including cardiac attack (myocardial infarction) and angina (chest pain).
  • Ischemic stroke: This is a stroke caused by reduced blood flow to the brain.

C. Poor immune response

Diabetes affects the immune system by reducing immune cell activity and increasing inflammation. The diseases include:

  • Respiratory tract disease
  • Restrictive lung disease
  • Lipohypertrophy

D. Additional complications of diabetes

  • Depression.
  • Skin infections
  • Hearing impairment

Complications of Gestational Diabetes

Most pregnancies are not affected by gestational diabetes and result in the birth of a healthy infant. Problems arise if diabetes isn’t treated and prenatal blood glucose levels aren’t regulated.

Lower-extremity Complications of Diabetes

Several factors contribute to diabetic foot ulcers, infections, and eventually amputations. These factors include neuropathy, poor foot biomechanics, peripheral arterial disease (PAD), and slow wound healing. Necrosis and gangrene can develop if the wound is not treated, necessitating amputation of the afflicted limb.

How to Prevent Complications of Diabetes?

  • Daily blood sugar checks
  • Healthy diet and exercise
  • Avoid alcohol drinking and smoke
  • Maintain a healthy mindset


It is vital to understand what is diabetes in order to overcome it. Treatment of type 1 and type 2 diabetes mellitus entails addressing numerous objectives, with glycemic control being the main objective. Maintaining glycemic control in diabetic individuals minimises many diabetes-related microvascular and macrovascular complications. Diabetes patients are living a longer and better life with fewer complications.