Diabetes Mellitus

Type 1 DiabetesType 2 Diabetes
  OnsetOften rapid, usually before age 30Often rapid, usually before age 30
  PrevalenceLess common, about 5-10% of all diabetes casesMore common, about 90-95% of all diabetes cases
  Risk FactorsFamily history, environmental factors, presence of damaging immune system cells (autoantibodies)Obesity, age, family history, history of gestational diabetes, impaired glucose metabolism, physical inactivity
  PathophysiologyAutoimmune destruction of insulin-producing beta cells in the pancreas, leading to absolute insulin deficiencyInsulin resistance – cells fail to respond to insulin correctly, with a relative insulin deficiency


  SymptomsPolyuria (excessive urination), polydipsia (excessive thirst), weight loss, fatigue, and often symptomatic hyperglycaemiaOften 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
  ManagementInsulin injections are always required, alongside dietary management and regular exerciseLifestyle modifications (diet, exercise, weight loss) are first-line, oral hypoglycaemic agents may be used, insulin may be required in later stages
  KetoacidosisCommon, due to lack of insulinLess common, unless under physical stress or if other health conditions are present
  ComplicationsSimilar for both types, including heart disease, stroke, kidney disease, eye issues, dental disease, nerve damage, and foot problemsSimilar for both types, including heart disease, stroke, kidney disease, eye issues, dental disease, nerve damage, and foot problems
  Diagnostic TestsPlasma glucose test, HBA1C test, autoantibody testing for type 1 diabetesPlasma 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)

  DiagnosisFasting Plasma  GlucoseHbA1c                           Random Plasma Glucose2-hour Post Prandial (OGTT)
  Normal< 5.5 mmol/l< 42 mmol/mol (6%)< 11.1 mmol/l< 7.8 mmol/l
  Prediabetes5.5 – 6.9 mmol/l42-47 mmol/mol (6-6.4%)N/A7.8 – 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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