Diabetes and hypertension

This article aims to provide a simple management plan for the management of people with diabetes mellitus who also have raised blood pressure (BP). It is based mainly on the current National Institute for Health and Care Excellence (NICE) recommendations. See also the Hypertension and Hypertension Treatment articles.

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, dyslipidaemia and obesity in these patients^{1 2} . Hypertension plays a major role in the development and progression of microvascular and macrovascular disease in people with diabetes³ .

Early intervention and targeting multiple risk factors with both lifestyle and pharmacological strategies give the best chance of reducing macrovascular complications in the long term⁴ .

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 placebo⁵ .

Epidemiology

• Hypertension is more prevalent in patients with type 2 diabetes than in those who don't have diabetes⁴ .

• 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 dyslipidaemia, hyperuricaemia, elevated fibrinogen and left ventricular hypertrophy.

Measuring blood pressure⁶

Measure standing as well as seated blood pressure. In people with a significant postural drop or symptoms of postural hypotension, treat to a blood pressure target based on standing blood pressure.

Measure blood pressure at least annually in an adult with type 2 diabetes without previously diagnosed hypertension or renal disease.

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

Management⁶

NICE recommends blood pressure management at 135/85 mm Hg for adults with type 1 diabetes. If they have albuminuria or two or more features of metabolic syndrome, recommend blood pressure management is at 130/80 mm Hg⁷ .

Reduce other risks of cardiovascular disease and other complications of diabetes - eg, smoking cessation, weight reduction, improvement of glycaemic control, and management of hyperlipidaemia¹ .

A Cochrane review found that evidence from randomised trials does not support BP targets any lower than 130/85 mm Hg for people with diabetes⁸ .

Drug treatment

• Offer an ACE inhibitor or an angiotensin-2 receptor blocker (ARB) to adults starting step 1 antihypertensive treatment who have type 2 diabetes. (NB: for adults of black African or African-Caribbean family origin, consider an ARB in preference to an ACE inhibitor.)

• If hypertension remains uncontrolled with an ACE inhibitor or ARB, offer the choice of a calcium-channel blocker (CCB) or a thiazide-like diuretic.

• If hypertension is still not controlled, offer a combination of an ACE inhibitor or ARB, a CCB and a thiazide-like diuretic.

• If hypertension is not controlled in adults taking the optimal tolerated doses of an ACE inhibitor or an ARB plus a CCB and a thiazide-like diuretic:

  • Regard them as having resistant hypertension.

  • Confirm elevated clinic blood pressure using ambulatory or home blood pressure recordings. Assess for postural hypotension.

  • For people with confirmed resistant hypertension, consider adding a fourth antihypertensive drug or seeking specialist advice.

  • Consider further diuretic therapy with low-dose spironolactone if blood potassium level is 4.5 mmol/L or less.

  • Consider an alpha-blocker or beta-blocker if blood potassium level is more than 4.5 mmol/L.

• If blood pressure remains uncontrolled in people with resistant hypertension taking the optimal tolerated doses of four drugs, seek specialist advice.

NB: always check safety and appropriate use of each medication for each individual patient - eg, pregnancy, breastfeeding and reduced renal function⁹ .