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 significantly higher risk of cardiovascular morbidity and mortality and are disproportionately affected by cardiovascular disease.¹²³ Most of this excess risk is associated with high prevalence of well-established risk factors such as hypertension, dyslipidaemia, and obesity in these patients.⁴ Hypertension plays a major role in the development and progression of microvascular and macrovascular disease in people with diabetes.¹

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.⁵

Thiazides and beta-blockers, whilst effective for blood pressure reduction, can cause increased insulin resistance making them less beneficial in diabetes. ACE inhibitors, and ARBs are cardio-protective and renally protective in diabetes and should be used for hypertension management.⁶

Epidemiology

• Hypertension is more prevalent in patients with type 2 diabetes than in those who don't have diabetes.⁴

• Hypertension occurs more commonly in patients with type 2 diabetes, with estimates of between 50 and 80%, whilst type 2 diabetes also occurs 2.5 times more often in patients with hypertension than those without.⁷

• 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 pressure⁸

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

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.

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

Management⁸

NICE recommends a blood pressure target of below 140/90 mm Hg for adults with type 1 diabetes and an albumin creatinine ratio of less than 70. If they have an ACR of more than 70, NICE recommends a blood pressure target of below 130/80 mm Hg. In adults with type 2 diabetes, the target remains below 140/90.

In adults over 80 with diabetes, the BP target is below 150/90.

American targets are lower than European targets, recommending blood pressure of below 130/80 mm Hg in all patients with diabetes.⁹

There is good evidence that reducing BP to these levels improves cardiovascular outcomes but there is also evidence that reducing blood pressure to less than 120/70 may increase adverse events.¹⁰¹¹

Reduce other risks of cardiovascular disease and other complications of diabetes - eg, smoking cessation, weight reduction, improvement of glycaemic control, and management of hyperlipidaemia.¹²

Drug treatment⁸

• 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 an ACE inhibitor causes side effects, an ARB should be offered instead.

• An ACE and ARB should not be combined for treatment.

• 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 function.¹³