Diabetes

Introduction to Diabetes in the Canadian Context

Diabetes is a chronic metabolic disorder characterized by elevated blood glucose levels. As a key topic for the MCCQE1 exam, understanding diabetes from a Canadian perspective is crucial for medical students preparing for their licensing exams.

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According to Diabetes Canada, approximately 11.5 million Canadians are living with diabetes or prediabetes. This high prevalence makes diabetes a critical area of focus for Canadian healthcare professionals and MCCQE1 candidates.

Types of Diabetes

Autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency

Type 1 Diabetes (T1D)

Etiology: Autoimmune destruction of pancreatic β-cells
Onset: Typically in childhood or adolescence, but can occur at any age
Treatment: Insulin therapy is essential

Type 2 Diabetes (T2D)

Etiology: Insulin resistance and progressive β-cell dysfunction
Risk Factors: Obesity, physical inactivity, age, family history
Treatment: Lifestyle modifications, oral medications, and/or insulin

Gestational Diabetes Mellitus (GDM)

Definition: Diabetes diagnosed in the second or third trimester of pregnancy
Screening: Universal screening at 24-28 weeks gestation in Canada
Management: Lifestyle modifications, blood glucose monitoring, and insulin if needed

Diagnostic Criteria for Diabetes in Canada

Canadian Diabetes Diagnostic Criteria

Diabetes Canada guidelines provide specific criteria for diagnosis:

Fasting Plasma Glucose ≥7.0 mmol/L
2-hour Plasma Glucose in a 75g OGTT ≥11.1 mmol/L
A1C ≥6.5% (in adults)
Random Plasma Glucose ≥11.1 mmol/L

Clinical Presentation and Complications

Common Symptoms

Polyuria
Polydipsia
Unexplained weight loss
Fatigue
Blurred vision

Acute Complications

Diabetic Ketoacidosis (DKA)
Hyperosmolar Hyperglycemic State (HHS)
Hypoglycemia

Chronic Complications

Microvascular Complications

Diabetic Retinopathy
Diabetic Nephropathy
Diabetic Neuropathy

Macrovascular Complications

Cardiovascular Disease
Cerebrovascular Disease
Peripheral Arterial Disease

Other Complications

Diabetic Foot Ulcers
Cognitive Impairment
Depression

Management of Diabetes in Canada

Lifestyle Modifications

Healthy eating patterns (following Canada's Food Guide)
Regular physical activity (150 minutes of moderate-to-vigorous aerobic exercise per week)
Smoking cessation
Stress management

Pharmacological Management

Type 1 Diabetes

Insulin therapy (multiple daily injections or insulin pump)
Carbohydrate counting and insulin dose adjustment

Type 2 Diabetes

Metformin (if not contraindicated)

Monitoring and Follow-up

Regular A1C testing (every 3 months)
Self-monitoring of blood glucose
Annual screening for complications
Regular foot examinations

Canadian Guidelines for Diabetes Management

The Diabetes Canada Clinical Practice Guidelines are updated regularly to provide evidence-based recommendations for diabetes care in Canada. Key points include:

Individualized A1C targets (generally <7.0% for most adults)
Emphasis on patient-centered care and shared decision-making
Recommendations for cardiovascular risk reduction in patients with diabetes
Guidance on the use of newer diabetes medications (e.g., SGLT2 inhibitors, GLP-1 receptor agonists)

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MCCQE1 candidates should be familiar with the latest Diabetes Canada Clinical Practice Guidelines, as they form the basis for diabetes management in Canadian clinical practice.

Key Points to Remember for MCCQE1

Know the diagnostic criteria for diabetes in Canada
Understand the differences between Type 1, Type 2, and Gestational Diabetes
Be familiar with the acute and chronic complications of diabetes
Know the first-line management strategies for Type 1 and Type 2 Diabetes
Understand the importance of individualized A1C targets
Be aware of the recommended screening intervals for diabetes complications
Know the Canadian guidelines for gestational diabetes screening and management

Sample Question

Question

A 55-year-old woman presents to her family physician with a 3-month history of increased thirst, frequent urination, and unexplained weight loss of 5 kg. She has a family history of diabetes. Her fasting plasma glucose is 7.8 mmol/L, and her A1C is 7.1%. Which one of the following is the most appropriate next step in management?

A. Start insulin therapy
B. Repeat fasting plasma glucose in 1 week
C. Start metformin therapy
D. Perform a 75g oral glucose tolerance test
E. Advise lifestyle modifications only

Explanation

The correct answer is:

C. Start metformin therapy

Explanation: This patient meets the diagnostic criteria for diabetes based on both her fasting plasma glucose (≥7.0 mmol/L) and A1C (≥6.5%). According to Diabetes Canada guidelines, metformin is the first-line pharmacological therapy for most patients with newly diagnosed Type 2 Diabetes, unless contraindicated. Lifestyle modifications should also be advised in conjunction with metformin therapy. Insulin is not typically the first-line treatment for newly diagnosed Type 2 Diabetes. An oral glucose tolerance test is not necessary as the diagnosis has already been established. Repeating the fasting glucose would delay appropriate treatment.

References

Diabetes Canada Clinical Practice Guidelines Expert Committee. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes. 2018;42(Suppl 1):S1-S325.
Public Health Agency of Canada. (2019). Diabetes in Canada. https://www.canada.ca/en/public-health/services/publications/diseases-conditions/diabetes-canada-highlights-chronic-disease-surveillance-system.html (opens in a new tab)
Lipscombe L, et al. Pharmacologic Glycemic Management of Type 2 Diabetes in Adults: 2020 Update. Can J Diabetes. 2020;44(7):575-591.
Canadian Diabetes Association. (2021). Diabetes Statistics in Canada. https://www.diabetes.ca/DiabetesCanadaWebsite/media/About-Diabetes/Diabetes%20Charter/2021-Diabetes-Canada-Cost-of-Diabetes-in-Canada.pdf (opens in a new tab)
Government of Canada. (2019). Canada's Food Guide. https://food-guide.canada.ca/en/ (opens in a new tab)

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