Epidemiology^[1]

• Hypertension is more prevalent in patients with type 2 diabetes than in the nondiabetic population.
• 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 renal disease and atherogenic risk factors including dyslipidaemia, hyperuricaemia, elevated fibrinogen and left ventricular hypertrophy.

Measuring blood pressure^[1][2]

Measure blood pressure (BP) at least annually in a person without previously diagnosed hypertension or renal disease. Offer and reinforce preventative lifestyle advice:

• Use a properly maintained, calibrated and validated device.
• Measure BP after sitting for 5 minutes (standing BP may have to be used if there is a possibility of orthostatic hypotension).
• Use a cuff of appropriate size, remove tight clothing, support the arm at heart level, ensure the hand is relaxed and avoid talking during the procedure.
• Record the mean of at least 2 readings - more than 2 if there is >10 mm Hg between the readings.

For a person on antihypertensive therapy at diagnosis of diabetes, review control of BP and medications used, and make changes only where there is poor control or where current medications are not appropriate because of microvascular complications or metabolic problems.

Repeat BP measurements within:

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

Offer lifestyle advice (see also separate article Diabetes Diet and Exercise) at the same time.

Management^[1]

• Offer lifestyle advice if blood pressure (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 hyperlipidaemia.
• 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 1-2-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).

Choice of drugs^[1]

Most patients with diabetes will require combination therapy with multiple antihypertensive drugs to achieve good control.

• First-line BP-lowering therapy should be a once-daily, generic angiotensin-converting enzyme (ACE) inhibitor. Exceptions to this are:
  • First-line BP-lowering therapy for a person of African-Caribbean descent should be an ACE inhibitor plus either a diuretic or a generic calcium-channel antagonist (calcium-channel blocker).
  • A calcium-channel blocker should be the first-line BP-lowering therapy 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 hyperkalaemia), substitute an angiotensin II-receptor antagonist (AIIRA) for the ACE inhibitor.
• 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 bendroflumethiazide, 2.5 mg daily). Add the other drug (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. A potassium-sparing diuretic must be used with caution if the patient is already taking an ACE inhibitor or an AIIRA.
• Monitor the BP of a person who has attained and consistently remained at his or her BP target every 4-6 months, and check for possible adverse effects of antihypertensive therapy, including the risks from unnecessarily low BP.

In known hypertensive patients who become diabetic, only modify drugs if there is poor control or where current medications are no longer appropriate because of microvascular complications or metabolic problems.

Notes

• An AIIRA should be substituted for the ACE inhibitor if there are persistent side-effects (eg chronic cough) - but not if there is deteriorating renal function or hyperkalaemia.
• Patients with diabetic nephropathy (including microalbuminuria) should be prescribed the full (or maximum-tolerated) dose of ACE inhibitor or AIIRA to achieve maximum renal benefit.
• Monitor renal function and electrolytes regularly for all patients on ACE inhibitors or AIIRAs, particularly after any change of dose.
• If control is still inadequate on third-line therapy, referral to a specialist should be considered.

Quality and Outcomes Framework indicators

The Quality and Outcomes Framework indicators (2011-2012) for blood pressure (BP) in patients with diabetes are:

• DM30. The percentage of patients with diabetes in whom the last BP is 150/90 mm Hg or less (8 points; payment stages 40-71%).
• DM31. The percentage of patients with diabetes in whom the last BP is 140/80 mm HG or less (10 points; payment stages 40-60%).