10 diabetes facts
Key Points
- Diabetes mellitus is a chronic metabolic disorder characterised by hyperglycaemia due to insulin deficiency, resistance, or both.
- It primarily exists in two forms: Type 1 and Type 2, with distinct aetiologies and management approaches
- Type 1 (10%) – DM1 – where the pancreas does not produce any insulin. This type is usually diagnosed in childhood or as a young adult
- Type 2 (90%) – DM2 – where the pancreas does not produce enough insulin or the body’s cells don’t react to insulin (resistance). This type usually affects older people.
- Early diagnosis and appropriate management are crucial in preventing complications such as cardiovascular disease, neuropathy, retinopathy, and nephropathy.
- Management focuses on lifestyle modifications, glucose monitoring, and pharmacological treatments.
- Education and regular monitoring are essential in the prevention and management of diabetes complications.
1. Definition
- Diabetes mellitus (DM) is a chronic condition characterised by elevated blood glucose levels (hyperglycaemia) resulting from either inadequate insulin production, impaired insulin action, or both
- It is classified mainly into Type 1 Diabetes (DM1), Type 2 Diabetes (DM2), and gestational diabetes, with other specific forms linked to genetic, drug-induced, or pancreatic disease.
2. Epidemiology
- Prevalence: Diabetes is a growing health concern worldwide, with over 4 million people diagnosed in the UK. Approximately 90% of cases are DM2, while 8% are DM1, and the remaining 2% are other specific types.
- Incidence: DM1 commonly presents in childhood or early adulthood, whereas DM2 typically occurs in middle-aged and older adults but is increasingly seen in younger populations.
- Gender: DM1 has no significant gender predilection, while DM2 slightly favours males.
- Trends: The incidence of diabetes, particularly DM2, is rising due to increasing rates of obesity, sedentary lifestyles, and an aging population.
3. Risk factors
Type 1 Diabetes
- Family history of DM1
- Genetic predisposition (e.g., HLA-DR3, HLA-DR4)
- Environmental factors (e.g. viral infections such as Coxsackie B, enteroviruses)
Type 2 Diabetes
- Family history of diabetes
- Obesity, particularly central adiposity
- Sedentary lifestyle
- Poor diet (high in refined carbohydrates and sugars)
- Age >45 years
- Ethnicity (higher risk in South Asian, African-Caribbean, and Black African populations)
- History of gestational diabetes
- Polycystic ovary syndrome (PCOS)
4. Causes
Type 1 Diabetes
- Autoimmune destruction of pancreatic beta cells, leading to absolute insulin deficiency.
- Genetic susceptibility combined with environmental triggers, such as viral infections, may precipitate the autoimmune response.
Type 2 Diabetes
- Insulin resistance in peripheral tissues (muscle, liver, adipose) and a relative insulin deficiency.
- Over time, the pancreas may fail to produce sufficient insulin to maintain normal blood glucose levels.
5. Symptoms
- Classic symptoms: Polyuria, polydipsia, polyphagia, and unintentional weight loss (more common in DM1).
- Other symptoms: Fatigue, blurred vision, recurrent infections (e.g., thrush, skin infections), slow-healing wounds, tingling or numbness in extremities.
- Type-specific presentation: DM1 may present acutely with diabetic ketoacidosis (DKA), while DM2 often has a more insidious onset and may be asymptomatic for years.
6. Diagnosis
Diagnostic criteria
- Fasting Plasma Glucose (FPG): ≥7.0 mmol/L
- Random Plasma Glucose: ≥11.1 mmol/L in symptomatic individuals
- HbA1c: ≥48 mmol/mol (6.5%)
- Oral Glucose Tolerance Test (OGTT): 2-hour plasma glucose ≥11.1 mmol/L
Note.Diagnosis requires confirmation with repeat testing unless symptomatic hyperglycemia is present.
Investigation
- Blood tests: FPG, random glucose, HbA1c
- Urinalysis: For glucose, ketones, and proteinuria (microalbuminuria)
- Autoantibodies: Anti-GAD, islet cell antibodies (to differentiate DM1 from DM2)
- C-peptide levels: To assess endogenous insulin production (lower in DM1)
- Lipid profile: For cardiovascular risk assessment
- Kidney function tests: To check for diabetic nephropathy
Differential diagnosis
- Type 1 vs. Type 2 Diabetes: Age of onset, body habitus, autoantibody presence
- Maturity-Onset Diabetes of the Young (MODY): Genetic testing may be required
- Gestational Diabetes: Diabetes diagnosed during pregnancy
- Secondary Diabetes: Resulting from other conditions (e.g. Cushing’s syndrome, pancreatitis, medication-induced)
7. Treatment
Type 1 Diabetes
- Insulin Therapy: Basal-bolus regimen, insulin pumps
- Lifestyle management: Nutritional counseling, regular exercise, monitoring of blood glucose levels
- Education: On carbohydrate counting, insulin adjustment, and management of hypoglycemia
Type 2 Diabetes
- Lifestyle Modifications: Diet, exercise, weight management
- Oral Hypoglycemic Agents: Metformin (first-line), sulfonylureas, DPP-4 inhibitors, SGLT2 inhibitors, GLP-1 agonists
- Insulin Therapy: May be required in advanced cases or when oral agents fail to control blood glucose
- Monitoring: Regular HbA1c checks, self-monitoring of blood glucose (SMBG)
8. Complications
Acute complications
- Diabetic Ketoacidosis (DKA): More common in DM1
- Hyperosmolar Hyperglycemic State (HHS): Typically seen in DM1
- Hypoglycemia: Due to insulin or sulfonylurea therapy
Chronic complications
- Microvascular: Retinopathy, nephropathy, neuropathy
- Macrovascular: Coronary artery disease, cerebrovascular disease, peripheral arterial disease
- Other: Diabetic foot, gastroparesis, sexual dysfunction
9. Prognosis
- Type 1 Diabetes: With good glycemic control, individuals can lead a normal, healthy life, though there is a lifelong dependence on insulin therapy. Poor control increases the risk of complications.
- Type 2 Diabetes: Prognosis varies based on glycemic control, comorbidities, and adherence to treatment. Early diagnosis and lifestyle modifications significantly improve outcomes.
10. Prevention
Type 1 Diabetes
- Currently, there is no effective method to prevent DM1. Research into immunomodulation and vaccine-like therapies is ongoing.
Type 2 Diabetes
- Lifestyle Modifications: Regular physical activity, a balanced diet, and weight management are effective in preventing or delaying the onset of DM2, especially in high-risk individuals.
- Medication: In some cases, metformin may be used in pre-diabetic patients to reduce the risk of progression to diabetes.
Other resource
MyHSN diabetes podcast (2024) – 9 min, 23 sec
Top Tip – Diabetes
Work hard on patients with early DM2 (and prediabetes), especially in the early months and years. You can help them slow its progression and even reverse it.
