Hypertension is one of the most common comorbidities in people with diabetes mellitus and is a major risk factor for cardiovascular disease, chronic kidney disease, diabetic retinopathy, and premature mortality. The coexistence of diabetes and hypertension markedly increases the risk of myocardial infarction, stroke, heart failure, peripheral arterial disease, and progression of diabetic nephropathy. Effective blood pressure control is therefore a fundamental component of diabetes management. In patients with type 2 diabetes mellitus (T2DM), angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are preferred because they reduce blood pressure, slow the progression of albuminuria, promote regression to normoalbuminuria, and help preserve renal function.

Pathophysiology

Hypertension in diabetes results from complex interactions between insulin resistance, endothelial dysfunction, chronic inflammation, activation of the renin–angiotensin–aldosterone system (RAAS), sympathetic nervous system overactivity, and sodium retention. Persistent hyperglycaemia damages blood vessels and impairs nitric oxide production, leading to increased vascular stiffness and peripheral vascular resistance. At the same time, diabetic kidney disease promotes sodium and fluid retention, further elevating blood pressure. Chronic hypertension accelerates both macrovascular complications, such as coronary artery disease and stroke, and microvascular complications, including nephropathy and retinopathy.

Risk Factors

• Long-standing diabetes mellitus

• Poor glycaemic control

• Obesity

• Sedentary lifestyle

• High dietary salt intake

• Chronic kidney disease

• Albuminuria or proteinuria

• Dyslipidaemia

• Smoking

• Advanced age

• Family history of hypertension

• Cardiovascular disease

Clinical Features

Hypertension is frequently asymptomatic and detected during routine blood pressure measurement.

Patients with severe or uncontrolled hypertension may present with:

• Headache

• Dizziness

• Blurred vision

• Fatigue

• Chest pain

• Shortness of breath

• Palpitations

Complications may include:

• Stroke

• Myocardial infarction

• Heart failure

• Chronic kidney disease

• Diabetic retinopathy

• Peripheral arterial disease

Diagnostic Criteria

Hypertension is diagnosed by persistent elevation of blood pressure measured on at least two separate occasions.

Blood pressure targets in diabetes

• General target: <140/90 mmHg

• Patients with microalbuminuria or proteinuria: <130/80 mmHg

• Lower blood pressure targets may be considered in younger patients and those at high risk of stroke if treatment is well tolerated.

Investigations

Baseline assessment

• Blood pressure measurement

• Body mass index (BMI)

• Urinalysis for albumin or protein

• Urine albumin-to-creatinine ratio (UACR), where available

• Serum creatinine and estimated glomerular filtration rate (eGFR)

• Electrolytes

• HbA1c

• Lipid profile

• Electrocardiogram (ECG) when indicated

Follow-up

• Blood pressure at every clinic visit

• Renal function and serum potassium after initiating or adjusting ACEIs or ARBs

• Urine albumin assessment annually

• Assessment for cardiovascular and renal complications

Management

Treatment Goals

• Achieve target blood pressure

• Reduce cardiovascular morbidity and mortality

• Slow progression of diabetic kidney disease

• Reduce albuminuria

• Prevent stroke, myocardial infarction, heart failure, and other complications

Non-Pharmacological Management

Lifestyle modification should accompany antihypertensive therapy and includes:

• Weight reduction if overweight or obese

• Regular physical activity (at least 150 minutes of moderate exercise per week)

• Reduced dietary salt intake

• Healthy balanced diet rich in fruits, vegetables, and whole grains

• Smoking cessation

• Limiting alcohol consumption

• Optimal glycaemic control

• Regular monitoring of blood pressure

Pharmacological Management

First-line therapy

People with diabetes should preferentially receive an ACE inhibitor (ACEI) or an angiotensin receptor blocker (ARB) because these agents reduce the progression of albuminuria, promote regression to normal albumin excretion, and may reduce the decline in renal function.

Recommended treatment:

Enalapril (PO) 10–40 mg daily, administered as a single daily dose or in two divided doses (5–10 mg twice daily)

OR

Losartan (PO) initial dose 50 mg once, followed by a maintenance dose of 25–100 mg daily as a single dose or in two divided doses.

Additional therapy

If blood pressure remains above target despite monotherapy, add one of the following:

Amlodipine (PO) 5–10 mg once daily

OR

Bendrofluazide (PO) 5 mg once daily

Important precautions

• Combination therapy with an ACE inhibitor and an ARB is not recommended.

• ACE inhibitors and ARBs should be discontinued before conception because of fetal toxicity.

• Diltiazem (PO) 60 mg once daily may be considered as an alternative antihypertensive agent for women planning pregnancy or when ACE inhibitors or ARBs are contraindicated.

Monitoring

Patients with diabetes and hypertension should be monitored regularly for:

• Blood pressure control

• Renal function

• Serum potassium after initiation or dose adjustment of ACEIs or ARBs

• Albuminuria or proteinuria

• Glycaemic control

• Cardiovascular complications

• Adherence to medication and lifestyle modification

Prevention

Hypertension in people with diabetes can be prevented or delayed through maintenance of a healthy body weight, regular physical activity, reduced salt intake, healthy eating habits, smoking cessation, moderation of alcohol consumption, and optimal glycaemic control. Routine blood pressure measurement at every clinic visit, early detection of albuminuria, and prompt initiation of antihypertensive therapy in eligible patients reduce the risk of cardiovascular disease and diabetic kidney disease.

Outcome

Effective blood pressure control substantially reduces the risk of stroke, myocardial infarction, heart failure, chronic kidney disease, diabetic retinopathy, and premature death in people with diabetes. Early initiation of ACE inhibitors or ARBs in patients with albuminuria provides additional renal protection by slowing the progression of diabetic nephropathy and preserving kidney function. Long-term adherence to treatment, regular monitoring, and healthy lifestyle practices are essential for achieving optimal cardiovascular and renal outcomes.