1. Chapter Overview: The "Organ Protection" Shift
The 2024 update reinforces a major paradigm shift: we are no longer just treating “sugar”; we are treating risk. The guidelines prioritize agents with proven cardiovascular and renal benefits (Cardiorenal Protection) for high-risk patients, often independent of their A1C levels.
For the CDE exam, you must distinguish between the “Glycemic Path” (lowering A1C) and the “Cardiorenal Path” (reducing heart failure, kidney disease progression, and stroke).
2. Key Messages (The "Gold Nuggets")
Metformin is (Usually) First: Metformin remains the initial agent of choice for most people due to safety, low cost, and efficacy.
The “Symptomatic” Exception: If a patient presents with metabolic decompensation (e.g., significant weight loss, severe hyperglycemia, ketosis), Insulin should be initiated immediately.
Cardiorenal Trumps A1C: In patients with Atherosclerotic CVD (ASCVD), Heart Failure (HF), or Chronic Kidney Disease (CKD), use an agent with proven benefit (SGLT2i or GLP-1 RA) even if their A1C is already at target.
Early Combination: If the A1C is >1.5% above target at diagnosis, start with Metformin + a second agent immediately (don’t wait 3 months).
3. Cardiorenal Protection (The "Big Three")
A. Atherosclerotic CVD (ASCVD)
Definition: History of MI, stroke, or revascularization.
Recommended Agents:
GLP-1 RA (with proven CVD benefit).
SGLT2i (with proven CVD benefit).
Goal: Reduce Major Adverse Cardiovascular Events (MACE).
B. Heart Failure (HF)
Definition: Reduced Ejection Fraction (HFrEF) or Preserved Ejection Fraction (HFpEF).
Recommended Agent: SGLT2 Inhibitor
C. Chronic Kidney Disease (CKD)
Definition: eGFR <60 mL/min or Albuminuria (ACR >2 mg/mmol).
Recommended Agents:
SGLT2 Inhibitor: Primary choice to slow progression.
GLP-1 RA: Alternative if SGLT2i is contraindicated or additional lowering is needed.
4. Drug Classes & Characteristics
5. Clinical Decision Algorithm (Summary)
Step 1: Assessment
Is the patient symptomatic/decompensated? -> Insulin +/- Metformin.
No? -> Proceed to Step 2.
Step 2: Baseline Therapy
Lifestyle Modifications + Metformin.
Exam Tip: If A1C is >1.5% above target, start Metformin + Second Agent.
Step 3: Cardiorenal Assessment (The Critical Junction)
Does the patient have ASCVD, HF, or CKD?
YES: Add SGLT2i or GLP-1 RA with proven benefit. (Do this regardless of A1C).
NO: Choose second agent based on goals:
Need Weight Loss? -> Tirzepatide, Semaglutide (GLP-1).
Avoid Hypo? -> DPP-4, SGLT2i, GLP-1.
Cost/Access Issues? -> Sulfonylurea, Insulin (NPH/Regular), TZDs.
Step 4: Monitoring
If not at target in 3–6 months, add another agent from a different class.
6. 2024 Diabetes Canada Clinical Practice Guidelines Recommendations
These are the “Must Memorize” graded recommendations.
First Line: Metformin should be the initial agent of choice in most people with type 2 diabetes.
Cardiorenal Risk: In adults with T2D and ASCVD, CKD, or HF, an agent with proven benefit (SGLT2i or GLP-1 RA) should be added to metformin.
Note: This decision is independent of A1C.
Heart Failure: SGLT2 inhibitors are specifically recommended for patients with a history of Heart Failure to reduce hospitalization.
Combination: In patients with A1C >1.5% above target, antihyperglycemic agents should be initiated concurrently (Metformin + Second Agent).