High blood pressure is the second main cause of disease burden in Australia and is only marginally behind tobacco, said Bruce Neal, senior director, research and development at the George Institute for International Health in Sydney, at a seminar organised by C3, Collaborating for Health. It’s the same in other developed countries and increasingly in developing countries. Yet Australia spends about $1 billion a year treating high blood pressure but makes little impact on the overall burden of disease resulting from high blood pressure. (Half the money goes on drugs and half on doctors and other health workers.) Why is there so little impact and how could Australia and other countries do better?
Many BMJ readers will know why the huge treatment effort, which is the same in other countries, has so little impact—but it’s worth reminding you.
Firstly, it’s people with “hypertension” who are being treated—above a systolic of about 140 mgHg. But the risk of developing a stroke, a heart attack, heart or kidney failure, or any of the other adverse effects of high blood pressure increases steadily from a systolic of about 115 mmHg. About half of the adverse effects happen in people who have “normal” blood pressure—because although they are at lower risk there are many more of them (the “prevention paradox.”)
Secondly, only about half of those who are hypertensive are diagnosed and treated, and, thirdly, only about half of those who are treated have their blood pressure reduced to below 140 mmHg. This is the familiar “rule of halves.” But to abolish risk patients need to have their blood pressure reduced below 115 mmHg, and this happens with virtually nobody. So overall only about 9% of the burden of disease from high blood pressure is countered by drug treatment.
What may be less familiar to BMJ readers is that the same or greater benefit could be achieved by a “gold plated” salt reduction scheme, which would cost about $10-20m, 1-2% of the spend on treatment. Plus the benefit would be additional to that from drug treatment.
Similar highly cost effective benefits can be achieved by reducing fat, sugar, and energy density in the processed foods that we all eat, but doctors think a lot about drugs and little about nutrition. Like most medical students I spent hundreds of hours learning about drugs but almost nothing about nutrition—and what I did learn was mostly about scurvy and other vitamin deficiencies. Sadly, I don’t think that it’s any better now.
Of course, doctors can prescribe drugs, but it’s hard to get individuals, particularly those on low incomes, to eat less salt, fat, and sugar—because most of what we eat is in processed foods. Doing something about food thus means either legislating or working with the food industry.
Many public health people are reluctant to work with the food industry. They think of the tobacco industry and its corrupt ways and conclude that voluntary efforts will never work. Professor Neal and most of those at the seminar, several from the food industry, think differently, pointing out that food is essential whereas tobacco is not, companies will reduce (and have reduced) the unhealthy components of their foods, and legislating on food and enforcing the legislation are much more difficult than doing so for tobacco.
But what should be helpful—no matter whether the way forward is legislation, voluntary codes, or a combination—is global, publicly available data on the composition of processed foods—and that’s what Professor Neal wants to achieve. These data can then be used to make comparisons with benchmarks of what’s regarded as healthy, among countries and companies, and over time.
Such a database has already been achieved in Australia, and—to my surprise—it’s mostly a matter of collating existing data. This about 50% of the data is supplied directly from food companies. More can then be gathered from websites, and some comes from patrolling supermarkets and reading labels. Random chemical analyses can be conducted to keep everybody honest.
Gathering these data can, Professor Neal believes, have a big impact in improving the world’s food supply—a bigger and more cost effective impact than relying simply on drugs.
Richard Smith was the editor of the BMJ until 2004. He also works for UnitedHealthGroup.