Diabetes Mellitus

Type 1 Diabetes Type 2 Diabetes
  Onset Often rapid, usually before age 30 Often rapid, usually before age 30
  Prevalence Less common, about 5-10% of all diabetes cases More common, about 90-95% of all diabetes cases
  Risk Factors Family history, environmental factors, presence of damaging immune system cells (autoantibodies) Obesity, age, family history, history of gestational diabetes, impaired glucose metabolism, physical inactivity
  Pathophysiology Autoimmune destruction of insulin-producing beta cells in the pancreas, leading to absolute insulin deficiency Insulin resistance – cells fail to respond to insulin correctly, with a relative insulin deficiency


  Symptoms Polyuria (excessive urination), polydipsia (excessive thirst), weight loss, fatigue, and often symptomatic hyperglycaemia Often asymptomatic in the early stages, may present with similar symptoms to type 1 when hyperglycaemia is significant, or with complications such as yeast infections or skin changes
  Management Insulin injections are always required, alongside dietary management and regular exercise Lifestyle modifications (diet, exercise, weight loss) are first-line, oral hypoglycaemic agents may be used, insulin may be required in later stages
  Ketoacidosis Common, due to lack of insulin Less common, unless under physical stress or if other health conditions are present
  Complications Similar for both types, including heart disease, stroke, kidney disease, eye issues, dental disease, nerve damage, and foot problems Similar for both types, including heart disease, stroke, kidney disease, eye issues, dental disease, nerve damage, and foot problems
  Diagnostic Tests Plasma glucose test, HBA1C test, autoantibody testing for type 1 diabetes Plasma glucose test, HBA1C test

Type 2 Diabetes Mellitus

Type 2 diabetes mellitus is a progressive disorder defined by deficits in insulin secretion and increased insulin resistance that led to abnormal glucose metabolism and related metabolic derangements.

Key Diagnostic Features

1. Presence of risk factors

2. Asymptomatic in early stages

3. Polydipsia (excessive thirst)

4. Polyuria (frequent urination)


Other Diagnostic Features

1. Recurrent candida infections

2. Skin infections

3. Urinary tract infections

4. Fatigue


Risk Factors

1. Older age

2. Overweight/obesity

3. Previous gestational diabetes

4. Non-diabetic hyperglycaemia (pre-diabetes)



i. Fasting plasma glucose

ii. HbA1c (glycated haemoglobin)

  Diagnosis Fasting Plasma  Glucose HbA1c                            Random Plasma Glucose 2-hour Post Prandial (OGTT)
  Normal < 5.5 mmol/l < 42 mmol/mol (6%) < 11.1 mmol/l < 7.8 mmol/l
  Prediabetes 5.5 – 6.9 mmol/l 42-47 mmol/mol (6-6.4%) N/A 7.8 – 11 mmol/l
  Diabetes ≥ 7 mmol/l ≥ 48 mmol/mol (6.5%)  11.1 mmol/l ≥ 11.1 mmol/l


1. Diagnosis of diabetes is confirmed by the presence of symptoms of diabetes along with at least one abnormal lab value.

2. If there are no symptoms, two abnormal readings of Fasting Blood Glucose on two separate occasions are required for diagnosis.



First Line Management

1. Lifestyle changes

2. Agree upon glycaemic (HbA1c) target.

3. Consider blood pressure management.

4. Consider lipid management.


If Metformin is Tolerated and Not Contraindicated:Non-Pregnant, HbA1c Above Goal

1. Metformin plus lifestyle measures, cardiovascular risk reduction, and specific considerations for chronic kidney disease (CKD)


HbA1c Above Goal on Metformin Monotherapy

1. Metformin plus additional antihyperglycemic agent


Further Reading: Type 1 Diabetes- NICE Guidelines

Further Reading: Type 2 Diabetes- NICE Guidelines

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