The partial update of the NICE hypertension guideline focuses on beta-blockers and the order in which drugs are prescribed, says Dr Rubin Minhas


   

Hypertension is a common condition, with an estimated 40% of the population thought to have raised blood pressure (using the gold standard of >140/90 mmHg).1 This undoubtedly has huge resource implications for the NHS, with approximately 90 million prescriptions issued every year, at a cost of approximately £800 million. This is around 15% of the total NHS drug budget.2

Hypertension and cardiovascular medicine are supported by a wealth of randomized clinical trial evidence, and the strong evidence base is reflected in the availability of clinical guidelines for managing hypertension. While the fundamental principles in previous British Hypertension Society (BHS)3 and NICE guidelines4 from 2004 were similar to each other, certain differences in management approach and sequence of initiation of antihypertensive drugs resulted in confusion surrounding the most appropriate way to manage hypertension in the minds of clinicians.These differences are mainly attributable to differences in guideline methodology. Selective ascertainment of evidence, which often occurs in guidelines from professional societies, can lead to differing conclusions from those guidelines developed using systematic searches to inform evidence-based recommendations.5

Guideline methodology

NICE guidelines are independent guidelines, produced without commercial sponsorship.The hallmarks of NICE guidelines are openness, inclusivity and accountability.

The development of a NICE guideline begins with the formulation of a number of clinical questions. A systematic search is then undertaken to identify any relevant published evidence. This evidence is reviewed and synthesized into an evidence statement using the hierarchy of evidence (Table 1).

Guideline development group (GDG) members are appointed from nominations received from a broad number of 'stakeholder groups' who are interested in the topic area. Members are required to declare any relevant conflicts of interest such as commercial or pharmaceutical interests, which might influence their decisions or affect the integrity of the guideline recommendations.

A GDG, comprising a representative number of healthcare professionals, is formed to develop the guideline recommendations. A marked contrast to traditional guidelines, such as those produced by professional societies, is the inclusion of patients in the GDG.

Table 1: Hierarchy of evidence and grades of recommendation

Reproduced by kind permission of the National Institute for Health and Care Excellence

Partial update of the hypertension guideline

The publication of the ASCOT study6 in 2005 presented an opportunity to update both the NICE and BHS guidelines, and address the lack of concordance between them. NICE announced that it would convene a GDG to undertake a partial update of the pharmacological chapter of its hypertension guideline. 7 A joint BHS/NICE group was convened to examine the updated evidence base and produce recommendations.

The ASCOT study suggested that beta-blockers were inferior to other anti-hypertensive drugs, such as calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors, in reducing the risk of stroke, and were more likely to predispose patients towards developing diabetes. The joint NICE/BHS group was given the task of appraising the evidence base, and producing a draft document for consultation. There were over 130 different stakeholder groups involved in the development of the guideline and the draft recommendations. 8

Order of prescribing

GPs use a number of drugs to reduce blood pressure.Many patients need at least two drugs; others require up to three or four different medications. For many of these patients, who are taking lifelong treatment, the sequence in which the drugs are initiated is largely academic.The aim of treatment is to reduce blood pressure.

NICE has dichotomized the initial treatment of hypertension (Figure 1) by the criteria of age and ethnicity:

  • in patients <55 years of age, first choice therapy should be an ACE inhibitor (Grade C)
  • in patients ?55 years of age, or for black patients of any age, first choice therapy should be either a calcium channel blocker or a thiazide-type diuretic (Grade A).

This recommendation is highly dependent on the cost of the calcium channel blocker chosen, as these drugs are not recommended where their cost exceeds £105 a year.9 Where patients require more than one drug, and initial treatment was with a calcium channel blocker or a thiazide-type diuretic, an ACE inhibitor should be used next (Grade B).

If initial therapy was with an ACE inhibitor, then subsequent therapy with a calcium channel blocker or diuretic should be initiated (Grade B). Where three drugs are required, the combination of an ACE inhibitor, a calcium channel blocker and a diuretic is recommended (Grade B).

If blood pressure remains uncontrolled on these three drugs, a fourth drug can be initiated, or the patient may be considered for further referral (Grade C). Where a clinician wishes to initiate a fourth drug, the options may include introducing a higher dose of a thiazide-type diuretic or another diuretic, which should be carefully monitored. Beta-blockers and alpha-blockers are alternatives (Grade C). The relegation of beta-blockers to fourth-line status is another key feature of the latest NICE hypertension guideline.7

The 'ACD' treatment algorithm is also recommended for patients with isolated systolic hypertension, as well as those with raised systolic and diastolic hypertension.

Figure 1: Treatment algorithm for patients with newly diagnosed hypertension

Choosing drugs for patients newly diagnosed with hypertension

Reproduced by kind permission of the National Institute for Health and Care Excellence

Beta-blockers: down but not out

One of the chief conclusions from the NICE hypertension partial update is the recommendation that beta-blockers are no longer preferred as initial therapy for hypertension (Grade B).This recommendation has the potential to impact significantly on GP workload if the nuances around its implementation are not clearly understood (Box 1).

Beta-blockers may still be considered for younger people, particularly women of childbearing potential, those with evidence of increased sympathetic drive, or patients with an intolerance or contraindication to ACE inhibitors or angiotensin receptor antagonists (Grade B).

Other concurrent indications for receiving treatment with beta-blocker therapy, such as symptomatic angina or previous myocardial infarction, are unaffected (Grade C).

The guideline recommends that if a patient is already taking a beta-blocker and requires another drug, a calcium channel blocker should be used rather than a thiazide-type diuretic so that the risk of new-onset diabetes is reduced.

It is important that clinicians do not distinguish between beta-blockers when implementing the NICE recommendations. The guideline notes that although atenolol has been the beta-blocker used in most of the studies examined, there is considerably less data to support other beta-blockers. GPs should, therefore, regard the NICE recommendation on beta-blockers as relating to the entire class.

It should be noted that beta-blockers have not been completely removed from the clinician's armamentarium, and they may still play a useful role in many situations.

For those patients whose blood pressure is well controlled by a beta-blocker, NICE emphasizes that there is no absolute indication to stop their medication, but their long-term treatment should be reviewed at the next opportunity.

Where a decision to withdraw beta-blockers is made, this should be done over several weeks, as up-regulation of beta-adrenoreceptors occurs during treatment and can result in 'rebound' adverse effects when beta-blockers are stopped suddenly.10

Box 1: Beta-blocker use in hypertension
  • Still have a compelling indication in symptomatic angina, or for patients who have had a previous myocardial infarction
  • Should generally be considered after diuretics, calcium channel blockers and ACE inhibitors – this applies to all beta-blockers
  • Younger people, particularly women of childbearing potential, those with evidence of increased sympathetic drive, or patients with an intolerance to ACE inhibitors or angiotensin II receptor antagonists may still benefit from beta-blockers
  • There is no absolute need to stop beta-blockers in individuals whose blood pressure is controlled with a beta-blocker-containing regimen
  • Where a decision is made to stop beta-blocker therapy, they should be reduced gradually over a matter of weeks

Back to basics

The guideline draws on the assumption that for all drugs within a class there is a class effect. This further supports the recommendation that the lowest cost drugs within each class should be used. Some other useful prescribing considerations are also highlighted, such as using once-daily drugs wherever possible.

Drug therapy is only one facet of managing hypertension. Although the NICE hypertension update is limited to pharmacological therapies, the role of lifestyle interventions is also briefly reinforced. The potential for withdrawing medication in those motivated to undertake lifestyle change is also emphasized, as is the need to involve patients in decisions about their care.

As with all recent NICE guidelines, a quick reference guide is available.11 This concise document provides an excellent summary of the key recommendations, including a particularly useful section on the correct way to measure blood pressure.

Implications for QOF2

This revision to previous hypertension guidelines is unlikely to have a substantial impact on achieving QOF2 targets.

Any theoretical benefit in applying a more effective treatment algorithm will be more than offset by the potential increase in workload arising from the downgrading of beta-blockers and recognition that, in clinical practice, many patients will be taking combinations of therapy involving two or three drug classes.

Conclusion

The high prevalence of hypertension requires clinicians to adopt a uniform, effective and evidence-based approach to diagnosing and managing this condition.

Given the conflicting views among clinicians over the ideal approach to managing blood pressure, constant commercial pressures to promote 'newer' medications, and significant differences of opinion on the treatment approach for hypertension, it has been a challenge to produce a guideline that is acceptable to the 130 stakeholders who participated in the NICE guideline development process.

The application of the NICE methodology has eventually resulted in a clear, impartial and evidence-based guideline that is likely to allow GPs to effectively target resources to help ensure a significant impact on improving the management of hypertension. Now the challenge for general practice is its implementation.

Implementation tools
NICE has developed the following tools to support implementation of its guideline on the management of hypertension in adults in primary care (partial update).They are now available to download from the NICE website: www.nice.org.uk.
Costing tools
National cost reports and local cost templates for the guideline have been produced.
Costing reports are estimates of the national cost impact arising from implementation based on assumptions about current practice, and predictions of how it might change following implementation of the guideline.

Costing templates are spreadsheets that allow individual NHS organizations and local health economies to estimate the costs of implementation taking into account local variation from the national estimates and quickly assess the impact the guideline may have on local budgets.

 

Guidelines in Practice, September 2006, Volume 9(9)
© 2006 MGP Ltd
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  2. North of England Hypertension Guideline Development Group. Essential hypertension: managing adult patients in primary care. Newcastle upon Tyne: Centre for Health Services Research, 2004.
  3. Williams B, Poulter N, Brown M et al. Guidelines for management of hypertension: report of the fourth working party of the British Hypertension Society, 2004; BHS IV. J Hum Hypertens 2004; 18 (3): 139–185.
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  11. National Institute for Clinical Excellence. Hypertension: management of hypertension in adults in primary care. Quick Reference Guide. NICE Clinical Guideline 34. London: NICE, 2004.