1. Overview & Targets
Hypertension affects fewer than 50% of people with diabetes, yet it is a major driver of cardiovascular disease (CVD), stroke, and nephropathy. Aggressive blood pressure (BP) control is often more effective at reducing CVD events than aggressive glycemic control.
Diagnostic Threshold: Hypertension in diabetes is defined as 130/80 mmHg.
Treatment Target: The goal for essentially all adults with diabetes is < 130/80 mmHg.
Note: This is lower than the general population target (often <140/90).
2. Diagnosis and Measurement
Method: Diagnosis should be based on proper in-office measurements (averaged) or, preferably, out-of-office measurements like Ambulatory Blood Pressure Monitoring (ABPM) or home monitoring to rule out “White Coat” hypertension.
Assessment: At diagnosis, assess for end-organ damage (retinopathy, nephropathy) and cardiovascular risk factors.
3. Management Strategy (The Algorithm)
The choice of initial medication depends heavily on the presence of existing complications or risk factors.
A. Lifestyle Intervention (First Line for All)
Weight: Achieve and maintain a healthy body weight.
Diet:
Sodium: Reduce intake to < 2,000 mg/day.
Pattern: DASH diet (high fruits/vegetables, low-fat dairy).
Potassium: Dietary potassium intake should be increased (unless renal insufficiency exists).
Alcohol: Limit to 2 drinks/day (men) and 1 drink/day (women).
Activity: Accumulate 150 mins/week of moderate-to-vigorous aerobic exercise.
B. Pharmacotherapy: Initial Choice
Scenario 1: With Cardiovascular or Kidney Disease
Indication: If the patient has known CVD, Chronic Kidney Disease (CKD), Albuminuria, or additional CV risk factors.
First Line: ACE Inhibitor (ACEi) or Angiotensin Receptor Blocker (ARB).
Rationale: These agents provide specific renoprotection and CV risk reduction beyond just lowering BP.
Scenario 2: No Complications/Risk Factors
Indication: Patient has diabetes and hypertension but no albuminuria, CVD, or other major risk factors.
First Line Options:
ACE Inhibitor
ARB
Dihydropyridine CCB (e.g., Amlodipine)
Thiazide-like diuretic (e.g., Indapamide, Chlorthalidone).
C. Combination Therapy
Most people with diabetes will require 2 or more agents to reach the target of <130/80 mmHg.
If not at target: Add a second agent from a different class.
Preferred Combinations:
ACEi/ARB + DHP-CCB (Dihydropyridine Calcium Channel Blocker).
ACEi/ARB + Thiazide-like diuretic.
Caution: Do not combine an ACEi with an ARB (risk of hyperkalemia/renal failure without added benefit).
D. Beta-Blockers?
Beta-blockers are NOT indicated as first-line therapy for uncomplicated hypertension in diabetes.
Exceptions: Use them if there is a specific cardiac indication (e.g., recent Myocardial Infarction, Heart Failure).
4. Special Considerations
Pregnancy:
Contraindicated: ACE inhibitors, ARBs, and Statins must be stopped prior to conception (teratogenic).
Safe Agents: Methyldopa, Labetalol, Nifedipine XL.
Renal Monitoring: When starting ACEi/ARB, monitor serum creatinine and potassium (expect a small, acceptable rise in creatinine; watch for hyperkalemia).
Orthostatic Hypotension: Monitor for drops in BP upon standing, especially in the elderly or those with autonomic neuropathy.
5. 2018 Diabetes Canada Clinical Practice Guidelines Recommendations
Key takeaways from the “Recommendations” section (Page S189).
Threshold & Target: People with diabetes should be treated to achieve a systolic BP < 130 mmHg [Grade C] and diastolic BP < 80 mmHg [Grade B].
Initial Therapy (with complications): For persons with CVD, CKD (including albuminuria), or additional CV risk factors, an ACEi or ARB is recommended as initial therapy [Grade A, Level 1A].
Initial Therapy (without complications): For others, acceptable initial choices include ACEi, ARB, DHP-CCB, or thiazide-like diuretic [Grade A to B depending on drug].
Add-on Therapy: If targets are not achieved, add a second agent. If initial therapy was an ACEi/ARB, a DHP-CCB is preferred over a diuretic [Grade A, Level 1A].
Pregnancy: Women trying to conceive should discontinue ACEi/ARBs [Grade D, Consensus].