Diagnosis and rational referral of glue ear
In the first of a new series on evidence-based practice, Bandolier editors Dr Andrew Moore and Professor Henry McQuay argue that investing more time and money in health promotion may be the most cost-effective way to cut heart disease deaths
Over the last year or so, UK health professionals and the public have been bombarded by messages about obesity, lack of exercise, healthy eating, salt, smoking, safe sex and teenage pregnancy
to name but a few. Media
have taken to criticising the 'nanny state' telling
us what to do with our lives.
We are no defenders of states or governments, but for some time the evidence has been accumulating that healthy lifestyle trumps anything medicine can offer, and is infinitely more effective than the multitudes of quackeries written about in our newspapers. The media seems to be oblivious to the irony of attacks on health promotion (for which there is a wealth of good evidence of massive effectiveness) at the same time as it promotes voodoo nonsense (for which there is good evidence of ineffectiveness
or no evidence of any effect).
Healthy living or treating
Time, then, for a look at the evidence about what is best: healthy living or treating the unhealthy?
There is a lot of evidence on the benefits of healthy living. Whether it is heart disease, cancer, bone density, arthritis, macular degeneration, or whatever, the message is the same the chance of having something nasty happen to you is very, very much reduced if you:
·have a good diet (lots of fruit and vegetables)
·take exercise (brisk walks several times a week)
·keep your weight in check (BMI below 30) and
·have a glass of what you fancy (in moderation).
One good example was from the US Nurses Study, which showed that those with a good diet, who did not smoke and who had enough exercise, had less than half the risk of heart disease compared with those who had none of these markers of healthy living. For those who additionally had a normal BMI and who drank alcohol moderately, the risk was down to a quarter. The trouble was that only one in eight female nurses was in the former category and only one in 30 in the latter.
Of course other factors such as poverty, unemployment, or living conditions, also come into play and can affect health significantly.
Wales (population about 2.5 million) has many of these issues and the economics of health in Wales has been examined with a very broad brush1. In 2001, 81 per cent of expenditure was on illness (£2.4 billion, or about £1,000 per person), while the spending on health promotion was 1,000 times less, at £2.3 million (or £1 per person). Each person in Wales had 13 prescriptions a year on average (it is 10 in England).
Technology or tomatoes?
Over the last few decades there have been large reductions in deaths from coronary heart disease in industrialised countries. There are two main reasons for this:
·treatments are better, both preventive and when a coronary event occurs
·known risk factors for coronary events (smoking, blood pressure, cholesterol) have changed for the better, and lower smoking rates, lower blood pressure and lower cholesterol result in fewer events, and therefore fewer deaths.
A number of studies have sought to evaluate which has done most (see table, page 63). In the UK, US and New Zealand, a rough answer is that about
40 per cent of the reduction comes from better treatments, and about 50-60 per cent from reduction in risk factors.
The numbers of deaths averted are not trivial, amounting to 68,000 a year in England and Wales in 2000 over what would have been expected from 1981, for instance. Moreover, efforts to improve coronary health appear to be cost-effective, with a US estimate extrapolating efforts in the 1990s to benefits up to 2015, producing a cost of $5,400 per life saved.
Large and long epidemiological studies7 can attribute only a proportion of the benefits from reduction in CHD deaths to classical risk factors.
Other unidentified changes must be having an influence. We, perhaps naively, like to think of this as the supermarket or tomato effect. People eat better than they did in the 1960s and 1970s, with fresh fruit and vegetables readily available all year round. Many have taken up exercise: there is an epidemic of people striding around to get their daily 20 minutes.
But beneficial behaviour is not evenly spread, and the supermarket and fast-food effect has the adverse effect of over-eating and obesity.
Changing the future
Most people with CHD have conventional risk factors. An analysis of 122,000 patients enrolled in 14 RCTs of CHD (myocardial infarction, unstable angina, and percutaneous coronary intervention) conducted in the 1990s showed that 85 per cent of women and 81 per cent of men had at least one conventional risk factor8.
If levels of risk factors keep falling, what does the future hold? The answer for the UK seems to be continued large reductions in CHD death rates9. Using Scottish data extrapolated to the UK, and extrapolating a continuation of current trends to 2010 for those under 75, it calculates 24,000 fewer deaths in 2010 from reductions in smoking prevalence, blood pressure and cholesterol. That is close to the UK Government target of 28,000 fewer deaths in 2010.
Bigger changes in population risk factors through lifestyle changes could produce bigger benefits. For instance, getting smoking prevalence down to
18 per cent, getting average cholesterol levels down to 5.2 mmol/L, and additional lowering of blood pressure by 3-4mmHg could double the number of deaths prevented or postponed.
All of this makes one wonder about that miserly £1 per person spent on health promotion. The evidence from the US Nurses Study is that more than half of them do not have a fully healthy lifestyle, despite the fact that nurses can be expected to be educated and informed. We also know that most people with CHD have risk factors.
There is clearly a job to be done to better inform people about how they can have a better and longer life. The solution, or at least a large part of it, lies in their own hands. Is 'nanny stateism' the best way? Who knows? The state does have enormous powers to improve the underlying culture. Anyone visiting New York or Ireland, where public place smoking bans are in force, can testify to impressive change for the better, with a large degree of public consent.
We spend masses on getting evidence about treatment effectiveness but not much on putting a healthy-living message across. Experience shows people respond best when given evidence rather than exhortation.
There are legitimate concerns about liberty and the rights of society. These extend to what the public health message is, and who delivers it. What is astonishing is that it is being delivered most publicly by those we are least inclined to believe.
But the bottom line is this: the reduction in conventional risk factors for CHD will also help a whole range of other conditions and leave us healthier for longer in several ways.
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1 Phillips and Tudor Edwards. Economics of health in Wales. Welsh Economic Review 2002 14: 6-30
2 Hunink et al. The recent decline in mortality from CHD, 1980/1990. The effect of secular trends in risk factors and treatment. JAMA 1997 277:535-42
3 Capewell et al. Contribution of modern cardiovascular treatment and risk factor changes to the decline in CHD mortality in Scotland between 1975 and 1994. Heart 1999 81: 380-5
4 Capewell et al. Explanation for the decline in CHD mortality rates in Auckland, New Zealand, between
1982 and 1993. Circulation 2000 102:1511-16
5 Goldman et al. The effect of risk factor reductions between 1981 and 1990 on CHD incidence, prevalence, mortality and cost. J Am Coll Cardiol 2001
6 Unal et al. Explaining the decline in CHD mortality in England and
Wales between 1981 and 2000. Circulation 2004 109:1101-07
7 Kuulasmaa et al. Estimation of contribution of changes in classic risk factors to trends on coronary event rates across the WHO MONICA project populations. Lancet 2000 355:675-87
8 Khot et al. Prevalence of conventional risk factors in patients with CHD. JAMA 2003 290:898-904
9 Critchley and Capewell. Substantial potential for reductions in CHD mortality in the UK through changes in risk factor levels. J Epidemiol Community Health 2003 57:243-7