Auckland, New Zealand - A new study has found that 80% of deaths connected to high blood pressure now occur in the developing world [1]. Dr Carlene MM Lawes (Clinical Trials Research Unit, University of Auckland, New Zealand) and colleagues also found that much of the burden is borne by people with prehypertension, so prevention and treatment strategies targeted to those with hypertension will miss much BP-related disease, they note in the Lancet.

"The take-home [message] from our research is the sheer staggering size of the problem," senior author Dr Anthony Rodgers (Clinical Trials Research Unit), told heartwire. "The other surprising thing is just how much of the burden is borne by people not currently targeted by current programs—most important, people at high risk in low- and middle-income countries." Rodgers also highlights the lack of response to this problem: "High blood pressure is a silent killer, and I imagine that is relevant—otherwise how could there not be more response to something that kills so many millions of people?"

Experts penning a strongly worded, accompanying commentary are somewhat harsher in their conclusions [2]. Dr Stephen MacMahon (University of Sydney, Australia) and colleagues say this situation with regard to high BP "was predicted a decade ago by the Global Burden of Disease Project, but none of the major health-development funds . . . have made any substantive or sustained effort to address this issue. Similarly, none of the major international drug companies have offered material assistance in this global health crisis, despite gargantuan profits from the sales of BP-lowering drugs in high-income countries."

In their report, Lawes et al provide updated estimates of the global burden of disease attributable to high BP (defined as 115 mm Hg systolic or greater) by age and sex for adults and by World Bank region for the year 2001. Data for systolic BP were obtained from the Global Burden of Disease 2000 study and updated to include more recent, country-level data, they note.

They show that 7.6 million premature deaths (about 13.5% of the global total) and 92 million disability-adjusted life-years—around 6% of the global total—were attributed to high BP. Worldwide, 54% of stroke and 47% of heart disease is due to high BP—about half of this was in people with hypertension (systolic BP 140 mm Hg or greater), while the remainder was in those with lesser degrees of high BP.

And while the proportion of premature deaths due to high BP was greater in high-income countries (17.6%) than in low- and middle-income nations (12.9%), the actual number of deaths related to high BP in richer countries was dwarfed by those in low- and middle-income countries: 1.39 million deaths compared with 6.22 million deaths.

Eastern Europe, Central Asia, East Asia, and the Pacific (including China), followed by South Asia (including India), bore the brunt of these high-BP-related deaths. More than one-third of all deaths in the lower-income countries of Europe and Central Asia region were related to high BP, for example.

The figures also show that, in low- and middle-income regions, a greater proportion of the burden of disease attributed to high BP was in young age groups than it was in high-income countries.

"Most of the disease burden caused by high BP is borne by low-income and middle-income countries, by people in middle age, and by people with lesser degrees of high BP," say the researchers.

"Prevention and treatment strategies restricted to rich countries or individuals with hypertension will miss much BP-related disease," they conclude.

In their editorial, MacMahon and colleagues wonder: "How big a problem does this have to become before anyone with resources takes meaningful action?"

Fortunately, reports from the World Health Organization and the World Bank "provide some hope that real action may be imminent," they note.

Both highlight the importance of chronic disease as an obstacle to economic development as well as a barrier to improved national-health status and "recommend action to control the huge epidemics of cardiovascular disease already affecting Asia and South America and threatening other regions, including Africa, where stroke is rapidly becoming a common cause of death and disability."

The risk of stroke is quickly reduced by BP-lowering drugs, and large benefits can be achieved with generic antihypertensives costing as little as $1 a year per person, say MacMahon et al. And effective nondrug interventions can also be provided at low cost, they note.

However, there is still a huge mountain to climb, they stress. For example, "there is no single initiative on the whole African continent to implement BP-control strategies systematically on a populationwide scale, even to those at very high risk of death or disability. For many such individuals, the first medically relevant attention they receive is admission to the hospital after stroke."

The major obstacle to the control of BP-related diseases in low- and middle-income countries is the absence of appropriate primary-healthcare services, the editorialists point out. Such services must be adapted to provide continuing care, not only for the management of BP-related diseases but also for the management of other serious chronic disorders, including HIV infection.

Unfortunately, however, research into healthcare delivery "is not attractive to most international funding agencies," they note, "many of which still prefer to believe that the world's leading health problems will be resolved by the development of new treatments based on technologies such as genomics, proteomics, or metabolomics." But for much of the world's population, any new drugs, however effective, "will have little relevance if there is no system in place to deliver treatment to those in need.

"The failure of primary-care systems combined with a myopic view of disease targets among those who set international health priorities has contributed to the staggering inequality in access to BP-lowering treatments. The antihypertensive care available for many people is much as it was in the first half of the 20th century, before the development of diuretics and beta blockers, where malignant hypertension was a common cause of hospital admission and death everywhere. This travesty cannot continue to be ignored by those most able to bring about change," they conclude.