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.
Top Tip
Work hard on patients with early DM2 (and prediabetes). You can help them slow its progression and even reverse it.
Other resource
MyHSN diabetes podcast (2024) – 9 min, 23 sec
