New NICE guidelines for hypertension

The recent updated guidance from the National Institute for Health and Clinical Excellence (NICE) on the management of hypertension in adults will have far reaching implications for day to day practice in the United Kingdom.1 2 The guidelines were developed in partnership with the British Hypertension Society and have 65 recommendations, 36 of which are new, with 12 listed as key priorities. Although these figures may seem daunting, closer scrutiny shows that most of the changes have evolved from previous guidelines and should be relatively straightforward to incorporate into clinical practice.

For the first time targets have been partially relaxed. Admittedly this applies only to people aged 80 or more, in whom a target blood pressure lower than 150/90 mm Hg is recommended. The previous target of 140/90 mm Hg is retained for everyone else, and this will continue to be a challenge in primary care.3 However, the guidelines clearly state that individual needs and preferences must be taken into account.1 They acknowledge that a balance must be struck between achieving targets and the realities of adherence to treatment and possible distressing side effects—particularly symptoms of postural hypotension.

The most noticeable change with regard to drug treatment concerns thiazides, which are no longer recommended as first line drugs unless other indications exist. Calcium channel blockers are preferred first drugs for patients over 55 years and those of Afro-Caribbean origin, with angiotensin converting enzyme inhibitors or angiotensin receptor blockers recommended for the rest. Indeed, bendroflumethiazide, the most commonly prescribed antihypertensive drug in Scotland, is no longer recommended for newly treated patients.1 4 Although widely used in the UK, it is less commonly prescribed in other countries or investigated in research studies, and it lacks a broad evidence base. Indapamide and chlortalidone are recommended as alternatives, although the new guideline supports the notion that patients whose blood pressure is well controlled by bendroflumethiazide need not be changed. There are few surprises in the other recommendations for drug treatment, including optimal combination treatment.

If all this seems incremental, the guidance on diagnosing hypertension is more radical. The guideline recognises the overtreatment of people with “white coat” hypertension and now recommends that ambulatory monitoring is offered to all patients with blood pressure values of 140/90 mm Hg or more in the clinic, although for severe hypertension (≥180/110 mm Hg), immediate treatment should be considered. Target organ damage should be investigated and cardiovascular risk formally assessed as part of the diagnostic investigation. A recent systematic review found that neither clinic nor home measurements have sufficient sensitivity or specificity as a single diagnostic test compared with ambulatory monitoring, which would result in more appropriately targeted treatment.5 This recommendation has important investment implications, especially for primary care, in terms of funding and maintenance of new equipment, staff training, and deployment costs. However, the cost effectiveness analysis that accompanies the new NICE guidelines supports the case for ambulatory monitoring by concluding that the additional costs incurred are counterbalanced by cost savings.6 It found that ambulatory monitoring was cost effective for men and women of all ages and cost saving for all groups (40-75 years). The median cost of a single ambulatory monitoring device was estimated at £1016 (€1160; $1638), and £380 was needed each year per device for servicing, calibration, and replacement of parts.6 Although consultation costs are shown, it is unclear whether these figures also include the computer support, staff training, and administration time that will be needed. Upfront primary care costs could therefore be higher and will vary appreciably between large and small general practices.

Is the case for comprehensive switching to ambulatory monitoring convincing enough? The evidence is persuasive: the benefits are that drug treatment will be targeted at those most likely to benefit because ambulatory monitoring is better than blood pressure measurement in the clinic at predicting those who will have cardiovascular events in the future.7 8 It should reduce inappropriate drug treatment in the estimated quarter of patients whose clinic blood pressure is inflated by the white coat effect.5 But ambulatory monitoring may not be the only option. In a recent meta-analysis, neither of the two studies of home blood pressure monitoring were inferior to ambulatory monitoring for predicting cardiovascular events (both were better than clinic blood pressure).5 Home blood pressure monitoring may be simpler to implement,9 and the NICE guidance recognises it as a suitable alternative for people who cannot tolerate ambulatory monitoring and for assessing response to treatment in people with white coat effect, as an adjunct to clinic blood pressure monitoring.2 It could also be considered as an interim option for general practices that presently lack ambulatory monitoring equipment.

Several important questions about ambulatory monitoring remain, including uncertainties about summary readings and the frequency of assessment.10 11 Although the role of ambulatory monitoring in the accurate diagnosis of hypertension has been further clarified,5 6 its optimal role still needs to be established for monitoring response to antihypertensive treatment.

Considerable challenges in implementation remain. On the basis of traditional clinic measurements, at least a quarter of all adults in the UK have hypertension—more than half of those over 60 years—and 12% of general practice consultations in 2006 were for hypertension.1 Prevalence will increase with an ageing population. General practices and emerging consortiums should therefore work closely with secondary care to develop local ambulatory monitoring implementation plans, which respond robustly to this step change in the diagnosis of hypertension.