Preventative medicine has been around a long time. The writers of classical antiquity such as Hippocrates and Galen felt that a regimen that included plenty of exercise and a good diet promoted health. As we found out more about diseases, it became clear that many could be prevented through avoiding what was clearly harmful, such as typhoid-infected water or cigarette smoke. Some infectious diseases could be prevented through vaccines. Public health measures such as improved sanitation and infant vaccination have arguably done more than anything else to improve the health of our population.
When we now talk about preventative medicine, we usually mean something rather different: modifying the risk factors that are associated with and may cause certain illnesses, such as heart disease, strokes or cancer. The growth in the technology of laboratory medicine has made it possible to measure many biological parameters, such as cholesterol and glucose levels, quickly and cheaply. The power of computers and the organisational abilities of large academic departments have made it possible to analyse enormous quantities of data to look for smaller and smaller associations between risk factors and illnesses. Modern researchers trawl through huge amounts of information in an effort to come up with something of significance. These results are often challenged and revised, so there is a constant ebb and flow of bewildering information, difficult for the doctor and patient to make sense of. We used to be exhorted to ‘go to work on an egg’. Eggs then became demonised as bearers of the deadly cholesterol, but now they help to combat Vitamin D deficiency and are not so bad after all. Whilst we worry about how many eggs to eat, the economic and social inequalities that are much more important determinants of health are largely ignored. Politicians find it convenient to hand over the public health agenda to GPs in their consulting rooms, who are given the responsibility to interrogate their patients about their exercise, diet and drinking habits. Those most in need of help in these areas are trapped in deprivation, and struggle to make changes. Major factors such as unemployment go unacknowledged, and interventions that could make a real difference such as minimum alcohol pricing are rejected.
The idea that we should aim to reduce the risk of developing an illness through preventative medicine is very seductive and highly political. It is thought to be more cost-effective to modify the risk factors in a population than treat the final condition, so prevention has become the paradigm in many countries. Politicians benefit because they think it saves money and looks as though they are caring. Pharmaceutical companies benefit from the huge expenditure on drugs to lower blood pressure, glucose and cholesterol. Academics and experts benefit from funding for research to bolster the claims. GPs are remunerated if they meet the targets for lowering blood pressure etc. So this alliance of vested interests pushes the preventative medicine agenda further and further as the goalposts are moved, definitions are broadened, and new ‘conditions’ such as ‘pre-hypertension’ and ‘pre-diabetes’ are described.
Do the patients benefit? The effects are so small that it is often difficult to know. For example a Cochrane Review of treating mild hypertension ( as GPs are encouraged to do and rewarded for in the UK) in otherwise well people over a 5 year period showed that there was no significant reduction in mortality, heart disease or stroke – but 9% of patients treated experienced side effects. A similar study looking at statins to prevent heart disease in well people showed that 60 people had to be treated for 5 years to prevent one heart attack. If you are that 1 in 60 then it probably would have been worth it. If you are one of the 59 then you would have had no benefit from the regular pill-taking, but could well have experienced side effects. We live in a society where people are so terrified of risk that many find it difficult to weigh up its significance. I recently saw a woman in her 80s who smoked heavily but who was worried because she put butter on her toast instead of margarine. The infinitesimally small risk associated with the butter was completely dwarfed by the huge risk from her age and smoking, yet she was so concerned by the warnings about the evils of butter that she was frightened about the harm that came from enjoying her breakfast.
The preventative medicine message is that danger and risk lurk in every uncorrected biological parameter and every bacon sandwich. The only salvation can come from embracing the benefits of modern drugs and repeated visits to the doctor. People have surrendered their trust in their own bodies as the miraculous self-correcting living organisms that they are and have become patients. In doing so they have lost something of their own humanity and human dignity.
Whilst all this has been going on, what about those people who really are unwell? In an era of finite or shrinking resources they have become the second class citizens. GPs are busy managing risk factors that were never going to cause an illness, coping with side effects from drugs that were of no benefit, and chasing up well people for health checks that they don’t really need. Inevitably this means less time for those who really are ill. So, people with no health problems become patients and sick people whom doctors were trained to help are neglected. Truly a victory for preventative medicine.