Management of Hypertension

Hypertension a major risk factor for cardiovascular disease (CVD - cerebrovascular event and ischaemic heart disease) and as such is one of the most important preventable causes of premature morbidity and mortality in developed and developing countries.

Yet studies still show that hypertension remains underdiagnosed, undertreated and poorly controlled in the UK.¹ The benefits of antihypertensive therapy in reducing the incidence of CVD and cerebrovascular event depend largely on blood pressure lowering - so achieving stated blood pressure (BP) targets is important.

• Measure BP in relaxed environment - patient sitting with arm outstretched, and supported.
• Ensure BP equipment is regularly validated and maintained.
• If initial BP >140/90 mm/Hg (or target) repeat later in the consultation if possible.
• If BP is different in both arms - take the higher reading as the reference in future and if there are postural symptoms take a standing BP to measure postural drop.
• Routine use of home monitoring devices or ambulatory BP devices is not recommended.
• Diagnosis - ideally this should require BP >140/90 mm/Hg on at least 3 occasions.

Drug treatment is recommended:

• In patients with sustained SBP ≥160 mm Hg or sustained DBP ≥100 mm Hg
• In patients with sustained systolic BP in the range 140-159 mm/Hg, and/or diastolic BP in the range 90-99 mm/Hg with known cardiovascular disease, diabetes, target organ damage (i.e. renal impairment); or an estimated CVD risk of ≥20% over the next 10 years using risk charts or calculator

NB:

• Patients with isolated systolic blood pressure or aged >80 should not be treated differently.
• Always take account taken of co-morbidity and other medications (prescribed or otherwise).
• BP treatment targets - titrate the doses of medication to the following targets, adding more drugs as necessary until further treatment is inappropriate or declined:
  • BP 140/85 mm/Hg (NICE says140/90 mm/Hg² - audit standard <150/90 mm/Hg)
  • BP 130/80 mm/Hg in patients with established CVD, chronic renal failure or diabetes (strive for optimal glycaemic control - HbA1c <7) NICE says 130/75 mm/Hg - audit standard <140/80 mm/Hg.

Based on JBS2 Guidelines 2005³ and NICE.^2,4Advise lifestyle measures in hypertensive, borderline hypertensive and patients with high normal BP (130-139/85-89 mm/Hg). Inform about any local initiatives, and supplement advice with leaflets or audiovisual information.

• Patients should stop smoking (offer help ± nicotine replacement therapy).
• Weight reduction should be suggested if necessary, to maintain ideal BMI of 20-25 kg/m². Offer a diet sheet and/or dietetic appointment. Dietary self-help e.g. dieting clubs, may be appropriate.
• Reduce their salt, total fat, saturated fat and cholesterol intake, while increasing consumption of polyunsaturated, monosaturated fats and oily fish. Encourage fruit, vegetables, legumes and whole grains; and low fat (or zero-fat) dairy, poultry meat, fish and shellfish products (as in the DASH eating plan).⁵
• Cut alcohol intake to no more than 21 units (male) or 14 units (female) of alcohol per week.
• Encourage regular dynamic exercise tailored to age and capabilities of patient. This may mean three vigorous training sessions per week for a young adult, or brisk walking for ≥30 minutes most days for the older individuals.
• Do not offer supplements of calcium, magnesium or potassium to reduce BP.⁶
• Relaxation therapy can help (PCT's not recommended to provide them routinely).
• As well as the targets above, strive for a happy, well-informed patient. Remember to look for and treat any underlying cause in your initial assessment (see hypertension article).

In the absence of contraindications or compelling indications for other anti-hypertensive drugs (see table below), follow the guideline algorithm as follows. NB: Black only refers to patients of African or Caribbean descent, not mixed-race, Asian or Chinese³

• Most hypertensives will need a combination of 2 or 3 drugs to achieve satisfactory control.
• Explain the need for long-term treatment "hypertension treatment should be continued until further notice - usually lifelong. If the patient agrees, enlist the spouse's help with diet and medication. Give clear verbal and written advice, and stress the importance of regular BP checks (± blood tests) and follow-up - including annual review (e.g. in "birthday month").
• Remember that most drugs take 4-8 weeks to produce their maximum effect and don't assess efficacy on the basis of a single clinic blood pressure measurement.
• Beta-blockers are no longer recommended by NICE as first line therapy, as they may be less effective in reducing major cardiovascular events, particularly stroke than other drug combinations.⁴
  • They may be appropriate in younger individuals who cannot tolerate ACEs or ACE IIs.⁷
  • Co-prescribing beta-blocker with CCB is better than a beta-blocker with a thiazide because of increased risk of developing diabetes.
  • If this combination is unavoidable, consider screening for diabetes regularly.
  • When hypertensive patients on beta-blockers are reviewed, the drug should be continued if there is a compelling indication for their use.
  • If the BP is being controlled on betablockers there is no absolute reason to stop them.⁴
  • If the BP is not being controlled the dose should be stepped down and stopped gradually, and replaced with a more appropriate drug as per algorithm above.

• Unless contraindicated, the guideline suggests prescribing low-dose aspirin and a statin for all people with IHD, and hypertensive patients aged >50 years who have a 10-year CVD risk ≥20% once BP is under control.³
• Also aim (in this group) to lower total cholesterol by 25% or LDL-cholesterol by 30% or achieve a total cholesterol of <4.0 mmol/l or LDL-cholesterol of <2.0 mmol/l, whichever is the greatest reduction.³

• Hypertension in the elderly: The absolute benefit of treatment is greater in the elderly. Patients tolerate BP treatment as well as younger age groups, so studies suggest optimum BP levels should be similar.
  • Beware older people show greater BP variability so more readings may be necessary (including standing BP) and titrate therapy to standing levels.
  • Isolated systolic hypertension should certainly be treated, although in borderline cases (140-159/<90 mm/Hg) without cardiovascular or target organ damage, resource and quality of life issues come to the fore.
  • Follow the drug choices as above, starting with calcium channel blocker or thiazide.
  • Benefits in those aged >80 have not been proven, but is the subject of current research (HYpertension in the Very Elderly Trial (HYVET) trial).
• Hypertension in the young: Always consider a secondary cause for hypertension (e.g. renal artery stenosis), particularly if difficult to control (consider consultant referral). Framingham risk data is not valid <32 years, and it is extremely unlikely that their CVD 10 year risk will be ≥20%. Balance long term risk with inconvenience of early treatment.
• Idiopathic hypertension in pregnancy: Methyldopa remains the first-line choice, with calcium antagonists (nifedipine) and hydralazine commonly used as second-line. Labetolol is often used for resistant third trimester hypertension. Avoid ACE-inhibitors and thiazides.¹²
• Hypertension and oral contraceptives: Generally patients with OCP induced hypertension or pre-existing hypertension should use non hormonal contraception, especially if there is co-existent migraine or CVD. If this is unacceptable, switching to the POP with careful BP monitoring is recommended.
• HRT and hypertension: HRT use is not generally associated with increasing BP, and HRT should not be denied to hypertensive women as long as BP can be controlled.
• Hypertension and ethnic groups: Black African-Caribbeans frequently have severe hypertension which often responds to salt restriction. They are sensitive to diuretics and calcium antagonists, but ACEs and β-blockers are often ineffective as monotherapy - unless used with diuretics, CCB or alpha blockers.^6,11

• At least every 6 months, frequency of visits depending on degree of control, complexity of therapy and compliance. Annual urinalysis for protein, blood for glucose, creatinine and electrolytes (± total and HDL cholesterol) and evaluation of CHD/CVD risk recommended: with routine visits to measure weight, BP and to enquire about general health, side-effects, treatment problems and to re-inforce non-drug measures. A robust call/recall system is essential.
• It may be possible to gradually titrate down or stop medication in patients who successfully modify their lifestyle (as long as appropriate BP and other targets are achieved, in patients with low cardiovascular risk).

• In order to improve the effectiveness of healthcare, most GP practices now have "practice protocols" for hypertension, asthma, diabetes, etc.. Local adaption and hence "ownership" of these is essential for their full implementation and effectiveness.
• All of the primary health care team should be involved in the initial design, with review dates and regular audits built in
• Guidelines should act as a catalyst for the practice's individual protocol.

Hypertensive care lends itself well to audit. The Quality and outcomes framework (QOF) quality indicators for hypertension are currently as follows (2006-7):