Patients with type 2 diabetes mellitus have a considerably higher risk of cardiovascular morbidity and mortality and are disproportionately affected by cardiovascular disease. Most of this excess risk is associated with high prevalence of well-established risk factors such as hypertension, dyslipidemia and obesity in these patients. Hypertension plays a major role in the development and progression of microvascular and macrovascular disease in people with diabetes.

Early intervention and targeting multiple risk factors with both lifestyle and pharmacological strategies give the best chance of reducing macrovascular complications in the long term.

Antihypertensive therapies may promote the development of type 2 diabetes mellitus. Studies indicate that the use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II receptor antagonists (AIIRAs) leads to less new-onset diabetes compared to beta-blockers, diuretics and placebo.

Epidemiology

• Hypertension is more prevalent in patients with type 2 diabetes than in those who don’t have diabetes.^[4]
• It is estimated that the prevalence of arterial hypertension (BP greater than 160/95 mm Hg) in patients with type 2 diabetes is in the range of 40-50%.
• Adults who have both diabetes and hypertension have more kidney disease and atherogenic risk factors including dyslipidemia, hyperuricemia, elevated fibrinogen and left ventricular hypertrophy.

Measuring blood pressure

Measure BP at least annually in an adult with type 2 diabetes without previously diagnosed hypertension or renal disease. Offer and reinforce preventative lifestyle advice. Repeat BP measurements within:

• One month if BP is higher than 150/90 mm Hg.
• Two months if BP is higher than 140/80 mm Hg.
• Two months if BP is higher than 130/80 mm Hg and there is kidney, eye or cerebrovascular damage.

Provide lifestyle advice (diet and exercise) at the same time. See also the separate Diabetes Diet and Exercise article.

Management

The following guidance has been taken from the NICE guideline for type 2 diabetes. The NICE guideline for type 1 diabetes states that the intervention levels for recommending BP management should be 135/85 mm Hg unless the person with type 1 diabetes has abnormal albumin excretion rate or two or more features of the metabolic syndrome, in which case it should be 130/80 mm Hg.^[7]

The Scottish Intercollegiate Guidelines Network (SIGN) recommends a target BP of diastolic ≤80 and systolic <130 mm Hg for people with diabetes.^[8]

• Offer lifestyle advice if BP is confirmed as being consistently above 140/80 mm Hg (or above 130/80 mm Hg if there is kidney, eye or cerebrovascular damage).
• Reduce other risks of cardiovascular disease and other complications of diabetes – eg, smoking cessation, weight reduction, improvement of glycaemic control, and management of hyperlipidemia.
• Add medications if lifestyle advice does not reduce BP to below 140/80 mm Hg (below 130/80 mm Hg if there is kidney, eye or cerebrovascular damage).
• Monitor BP 1- to 2-monthly, and intensify therapy if on medications, until BP is consistently below 140/80 mm Hg (below 130/80 mm Hg if there is kidney, eye or cerebrovascular disease).

A Cochrane review found that evidence from randomized trials does not support BP targets any lower than 130/85 mm Hg for people with diabetes.

NICE guidance

Provide lifestyle advice if BP is confirmed as being consistently above 140/80 mm Hg (or above 130/80 mm Hg if there is kidney, eye or cerebrovascular damage).

Add medications if lifestyle advice does not reduce BP to below 140/80 mm Hg (below 130/80 mm Hg if there is kidney, eye or cerebrovascular damage).

Monitor BP every 1-2 months and intensify therapy if the person is already on antihypertensive drug treatment, until the BP is consistently below 140/80 mm Hg (below 130/80 mm Hg if there is kidney, eye or cerebrovascular damage).

Drug treatment

• First-line antihypertensive drug treatment should be a once-daily ACE inhibitor. Exceptions to this are people of African or Caribbean family origin, or women for whom there is a possibility of becoming pregnant.
• The first-line antihypertensive drug treatment for a person of African or Caribbean family origin should be an ACE inhibitor plus either a diuretic or a calcium-channel blocker.
• A calcium-channel blocker should be the first-line antihypertensive drug treatment for a woman for whom there is a possibility of her becoming pregnant.
• For a person with continuing intolerance to an ACE inhibitor (other than renal deterioration or hyperkalemia), substitute an angiotensin II-receptor antagonist for the ACE inhibitor.
• Do not combine an ACE inhibitor with an angiotensin II-receptor antagonist to treat hypertension.
• If the person’s BP is not reduced to the individually agreed target with first-line therapy, add a calcium-channel blocker or a diuretic (usually a thiazide or thiazide-related diuretic). Add the other drug (that is, the calcium-channel blocker or diuretic) if the target is not reached with dual therapy.
• If the person’s BP is not reduced to the individually agreed target with triple therapy, add an alpha-blocker, a beta-blocker or a potassium-sparing diuretic (the last with caution if the person is already taking an ACE inhibitor or an angiotensin II-receptor antagonist).

Monitor the BP of a person, who has attained and consistently remained at his or her BP target, every 4-6 months.