Diabetes with Hypertension

This article aims to provide a simple management algorithm for the management of people with diabetes mellitus who also have raised blood pressure, making sense of the numerous (sometimes conflicting) published guidelines.

• Hypertension is more prevalent in patients with type 2 diabetes than in the nondiabetic population.
• It is estimated that the prevalence of arterial hypertension (blood pressure 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.

Measure blood pressure 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 blood pressure after sitting for 5 minutes (standing blood pressure 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 mean of at least 2 readings - more than 2 if there is >10 mm Hg between the readings.

• Initially, trial lifestyle advice: dietary advice, reduce salt intake (<6 g/day), increase aerobic exercise.
• Reduce other risks of cardiovascular disease and other complications of diabetes, e.g. smoking cessation, weight reduction, improve glycaemic control, and management of hyperlipidaemia.
• Rigorous control of blood pressure.
  NICE recommends a risk approach centered on a target blood pressure:
  • Target of <140/80 mm Hg for most people with type 2 diabetes
  • Target of <130/80 mm Hg for those at more particular risk including those with signs of target organ damage:^1,2,3
    • Established ischaemic heart disease
    • Cerebrovascular disease (stroke or transient ischaemic attack)
    • Diabetic nephropathy (raised albumin excretion rate (microalbuminuria or proteinuria), eGFR <60 ml/min/1.73 m² or chronic renal failure - patents should already be on the maximum tolerated dose of ACE inhibitor
    • Diabetic or hypertensive retinopathy
    • Left ventricular hypertrophy (ECG or echocardiogram)

Choice of drugs¹

Most patients with diabetes will require combination therapy with multiple antihypertensive drugs to achieve good control. 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.¹

• First-line therapy: ACE inhibitors should be considered first-line in diabetics with hypertension because of their beneficial renal effects, except:
  • In patients of African-Caribbean descent (use an ACE inhibitor plus either a calcium channel blocker (CCB) or a diuretic)
  • In women of child-bearing age where, after informed discussion with the patient there is a chance of pregnancy, use a CCB
• Second-line therapy: add in a CBB and/or diuretic (i.e. dual or triple therapy) if blood pressure remains above target.
• Third-line therapy: if triple antihypertensive therapy is not adequate, add an alpha-blocker, a beta-blocker or a potassium-sparing diuretic (watch carefully for hyperkalaemia if the patient is on an ACE inhibitor or an angiotensin-II receptor antagonist (ARB)).

Notes

• An angiotensin-II receptor antagonist should be substituted for the ACE inhibitor if there are persistent side-effects (e.g. 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 ARB to achieve maximum renal benefit.
• Monitor renal function and electrolytes regularly for all patients on ACEs or ARBs, particularly after any change of dose.
• If control is still inadequate on third-line therapy, referral to a specialist should be considered.

Follow-up

Repeat blood pressure measurements within:

• One month if blood pressure is higher than 150/90 mm Hg
• Two months if blood pressure is higher than the target (140/80 mm Hg or 130/80 - see above)
• Four to six months if blood pressure is at or below the target

The Quality and Outcomes Framework indicators for blood pressure in patients with diabetes are:

• The percentage of patients with diabetes who have a record of the blood pressure in the previous 15 months (3 points; payment stages 40-90%)
• DM 12. The percentage of patients with diabetes in whom the last blood pressure is 145/85 or less (18 points; payment stages 40-60%)

NICE has recommended DM 12 be split for 2010-11 into two separate indicators: 150/90 (higher level blood pressure target) and 140/80 for those with a lower target. Fuller details are awaited.

1. Type 2 diabetes: the management of type 2 diabetes (update), NICE Clinical Guideline (May 2008)
2. Williams B, Poulter NR, Brown MJ, et al; British Hypertension Society guidelines for hypertension management 2004 (BHS-IV): summary. BMJ. 2004 Mar 13;328(7440):634-40.
3. No authors listed, JBS 2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice. Heart. 2005 Dec;91 Suppl 5:v1-52.