Despite the availability of multiple pharmacotherapies and the known preventative effects of lifestyle modification, hypertension remains a highly prevalent disorder worldwide. Indeed, high blood pressure (BP) is estimated to result in approximately half of the global burden of all cardiovascular disease (WHO. Global health risks: mortality and burden of disease attributable to selected major risks. WHO Press, Geneva, 2009). Because of the global impact of this disorder, and because of its modifiable nature, Nature Reviews Cardiology and the World Heart Federation are holding a joint session on 'Hypertension in 2012' at this year's World Congress of Cardiology in Dubai, UAE. The session will cover community-wide strategies for prevention of hypertension, BP measurement and targets, the latest advances in antihypertensive therapies, and management of hypertension in the elderly. Review articles that accompany two of the talks in this session (written by the commissioned speakers) are included in this focus issue of Nature Reviews Cardiology. An additional article that highlights the current challenges in management of this condition is also included.

Clearly, a substantial proportion of patients are being incorrectly managed...

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As explained in Luis Ruilope's Review in this issue of Nature Reviews Cardiology, the validity of clinic BP measurement has increasingly been questioned over the past 20–30 years, owing to increased awareness of 'white-coat' and 'masked' hypertension. 'White-coat', or 'isolated clinic', hypertension—a condition in which patients persistently have elevated BP levels in the presence of a health-care professional, but normal out-of-clinic BP—is thought to account for approximately one-third of all patients identified as having elevated BP in the clinic (Mancia, G. et al. Long-term risk of mortality associated with selective and combined elevation in office, home and ambulatory blood pressure. Hypertension 47, 846–853; 2006). Clearly, a substantial proportion of patients are being incorrectly managed. In recognition of this problem and the costs associated with it, the UK's National Institute for Health and Clinical Excellence recommended that ambulatory BP measurement be offered to all patients with clinic BP ≥140/90 mmHg in the August 2011 update of their hypertension guidelines (National Institute for Health and Clinical Excellence. CG127 Hypertension: full guideline [online], http://www.nice.org.uk/nicemedia/live/13561/56007/56007.pdf; 2011). Encouragingly, early signs indicate that at least some UK doctors have followed this guidance; in mid March, one provider of 24-h ambulatory BP monitors (Welch Allyn) reported a 350% increase in UK sales of these devices over the preceding few months.

The inverse condition to white-coat hypertension—normal BP in the clinic, but elevated BP when measured at home or over a 24-h ambulatory period—is thought to affect approximately one in eleven patients (Mancia, G. et al. Long-term risk of mortality associated with selective and combined elevation in office, home and ambulatory BP. Hypertension 47, 846–853; 2006). Known as 'masked' hypertension, this condition is associated with its own unique challenges, since clinicians are unlikely to obtain 24-h ambulatory BP measurements, or even home BP measurements, for patients who present with normal BP in the clinic. Discussion and consideration of this problem are needed, particularly because masked hypertension is associated with a high prevalence of organ damage as well as increased cardiovascular risk and all-cause mortality (Mancia, G. et al. Diagnosis and management of patients with white-coat and masked hypertension. Nat. Rev. Cardiol. 8, 686–693; 2011).

Dr Ruilope also mentions that clinicians are becoming increasingly aware of the impact of variability in BP measured in one location on a regular basis. In 2010, Peter Rothwell and colleagues demonstrated that clinic visit-to-visit variability in systolic BP is associated with increased risk of stroke, regardless of mean systolic BP (Rothwell, P. M. et al. Prognostic significance of visit-to-visit variability, maximum systolic blood pressure, and episodic hypertension. Lancet 375, 895–905; 2010). In the following year, the NHANES investigators reported that high short-term visit-to-visit variability in systolic BP is associated with increased all-cause mortality (Muntner, P. et al. The relationship between visit-to-visit variability in systolic blood pressure and all-cause mortality in the general population: findings from the NHANES III, 1988 to 1994. Hypertension 57, 160–166; 2011). In line with these findings, two studies assessing the impact of variability in BP measured in the home environment found that morning day-by-day variability was predictive of cardiovascular events (Johansson, J. K. et al. Prognostic value of the variability in home-measured blood pressure and heart rate: the Finn-Home Study. Hypertension 59, 212–218; 2012) and mortality (Kikuya, M. et al. Day-by-day variability of blood pressure and heart rate at home as novel predictor of prognosis: the Ohasama study. Hypertension 52, 1045–1050; 2008) in representative samples of the general population. Further research is needed to determine how the diagnosis and management of BP variability should be addressed in everyday practice.

BP targets are another issue that has received much attention over the past few years. Multiple trials published since 2009 have indicated that lowering BP to <120/80 mmHg can be dangerous in patients with established cardiovascular disease and of no benefit to patients with diabetes mellitus. The current consensus seems to be that, rather than recommending that patients aim for BP <130/80 mmHg, physicians should set a BP target of 130–139/80–85 mmHg. Of course, keeping patients motivated to adhere to their antihypertensive therapeutic regimen to attain and sustain such a BP is another huge challenge that has been the focus of multiple studies over the past few years, one of which (Ogedegbe, G. O. et al. A randomized controlled trial of positive-affect intervention and medication adherence in hypertensive African Americans. Arch. Intern. Med. 172, 322–326; 2012) is discussed in a News & Views article by William Shrank and Niteesh Choudry in this issue of Nature Reviews Cardiology.

Numerous antihypertensive pharmacotherapies are available for patients who cannot achieve their target BP by lifestyle modification alone. However, despite the abundance of choice, the current high prevalence of hypertension indicates a need for additional therapeutic strategies to be developed. As discussed by Thomas Unger and colleagues in this issue of Nature Reviews Cardiology, rather than bringing us multiple new pharmacotherapies, the past few years of research have instead provided novel fixed-dose combinations of existing drugs and new nonpharmacological therapeutic strategies. Indeed, the advent of the device-based baroreflex activation therapy and the renal sympathetic denervation strategy—the latter of which is actually an old idea that has been 'reincarnated' with the development of minimally invasive, catheter-based technology—are particularly exciting developments, as they might help to reduce the problem of 'treatment-resistant' hypertension. In a Research Highlight published in this issue of Nature Reviews Cardiology, we summarize the findings of a new study (Brandt, M. C. et al. Renal sympathetic denervation reduces left ventricular hypertrophy and improves cardiac function in patients with resistant hypertension. J. Am. Coll. Cardiol. 59, 901–909; 2012) that has demonstrated for the first time that the beneficial BP-lowering effects of renal sympathetic denervation are associated with improved cardiac function.

The prevalence of hypertension increases substantially with age and given that the elderly proportion of the population is growing rapidly, the management of this group of patients deserves considerable attention. In their Review, Eduardo Pimenta and Suzanne Oparil discuss the common problems associated with the diagnosis and management of hypertension in the elderly, including the phenomena of 'pseudohypertension' and postural and postprandial hypotension, and the high likelihood of comorbidity and polypharmacy. They also highlight important considerations when deciding on the form of antihypertensive treatment to employ, and the latest research on how aggressively to control BP in these patients.

Studies published over the past few years have had a huge impact on the way in which clinicians are approaching the diagnosis and management of this highly prevalent condition, and have provided much 'food for thought' for future guideline-writing committees. We hope that you enjoy our round-up of the latest developments in clinical hypertension research.