At least two thirds of tests and investigations ordered by doctors are unnecessary

April 10, 2024 by Doctor Vernon Coleman

The following essay is taken from `The Health Scandal’ by Vernon Coleman.

After studying dozens of scientific papers on the subject, talking to scores of hospital doctors and GPs and spending over ten years practising medicine within the NHS I am convinced that at least two-thirds of all tests and investigations ordered by doctors are unnecessary. Every year thousands of doctors practise blunderbuss therapy and order huge numbers of unnecessary tests.

A hundred years ago there were hardly any diagnostic tests available. Then the only hazard was that a doctor would 'over-treat' his patients. Today a doctor can choose from thousands of individual tests and over investigation probably leads to even more problems than overtreatment. Unnecessary tests can be misleading, time consuming, painful, expensive, and dangerous.

In 1980, A. Stilwell and two colleagues wrote an article entitled 'Evaluation of Laboratory Tests in Hospitals' (which was published in the Annals of Clinical Biochemistry). They confirmed that many tests were requested thoughtlessly, wasting resources. In 1979, in an article entitled 'Cost of Unnecessary Tests' in the British Medical journal, Sandler showed that the routine examination of blood and urine contributed to only one per cent of the diagnoses made. In June 1987 in an article entitled 'Are Routine Bacteriological Cultures Necessary in an Accident and Emergency Department?', published in the British Medical Journal, Drs Hashemi and Merlin from the Accident and Emergency Department at Walsall General Hospital in the West Midlands produced some startling figures. They pointed out that 'microbiology services receive many requests that cannot reasonably be expected to influence management of patients.' Their study was designed to evaluate the usefulness of taking bacteriological swabs in the accident and emergency department of a district general hospital. Their conclusion was that 'routine sampling for microbiological testing is unnecessary.' Astonishingly they reported that in only three per cent of cases was the treatment given based on the result of culture and antibiotic sensitivity. Moreover, they pointed out that in over sixty per cent of cases the patient was discharged before the results of culture were available.

Doctors over investigate their patients for a number of reasons. First, over investigation is a habit that doctors are taught when young. Young students and newly qualified doctors are encouraged by consultants to order all the available tests as though they were getting special wholesale rates. Consultants encourage this behaviour by criticizing students mercilessly for not ordering as many tests as can possibly be done. No thought is given to the cost of all these investigations, no attempt is made to decide which tests are particularly likely to help doctors reach a diagnosis, and no thought is given to the patient who will spend hours and days wandering from laboratory to X-ray department and will end up exhausted and exsanguinated.

Secondly, doctors order tests in order to impress their students, their colleagues, their patients or themselves. The more esoteric the test the greater the status associated with its use.

Thirdly, doctors frequently order unnecessary tests because they are planning to write papers for scientific journals and because they need lots of data to fill up their pages and help build up their reputations. Most of the papers published in this way are of little or no genuine clinical value.

Fourthly, tests are sometimes performed in order to protect doctors from the risk of litigation. So, for example, doctors in hospital casualty departments will frequently order unnecessary X-rays in order to protect themselves against any possible accusation of negligence. Occasionally, there is some slight justification for this nervousness. On the whole, however, this fear is misplaced.

Fifthly, many doctors practice 'hot' or aggressive medicine and insist on collecting all the possible evidence they can even when the diagnosis is not in doubt.

Sixthly, unnecessary tests are often ordered to buy doctors time when they don't know what is going on. They hide behind technology and seek reassurance and comfort from more and more new tests. The condition of the patient becomes almost irrelevant as they search for that ever-elusive diagnosis.

Finally, many doctors perform unnecessary tests simply and solely because that's how it's always done. So, for example, patients who are in hospital will often have daily blood tests even though there is absolutely no need for daily blood results and even though a daily change in the results obtained is unlikely to lead to a daily change in the treatment provided. In other words investigation and diagnosis have been completely divorced from treatment!

There are, of course, a number of hazards associated with this fetish for over investigation. One of the most important anxieties I have is that tests and investigations are often extremely dangerous. Not surprisingly, perhaps, relatively few scientific papers have been published describing the dangers associated with hospital tests but there have been some papers published and some figures are available.

For example, in a paper entitled 'Frequency and Morbidity of Invasive Procedures', published in the Archives of Internal Medi­ cine in December 1978, three physicians from the Departments of Medicine at the University of California and Stanford University showed that fourteen per cent of all patients who underwent invasive procedures (such as biopsies, catheterizations or bronchoscopies) had at least one complication. Most complications then need treatment and involve a longer stay in hospital for the patient.

Even patients who have been to hospital and had simple basic blood tests will know that occasionally things can go wrong. Some­ times the problem is simply an escape of blood into the tissues with the development of a painful swelling. But sometimes more serious problems can develop. Arteries can be punctured or nerves can be hit accidentally. The majority of doctors (and nurses) regard blood letting as a trivial task. In fact it is painful, expensive, and potentially dangerous. And, more often than not, unnecessary.

The second big problem with investigations is that they often produce 'false positives'. In other words although patients do not have a particular disease a test may show, wrongly, that they do have that disease. The consequences of this vary.

When the first blood test for syphilis was introduced doctors accepted it as accurate. It wasn't until several decades later that doctors found that fifty per cent of all the patients whose blood test had shown them to have syphilis didn't have syphilis at all. The lives of many of those patients must have been ruined quite unnecessarily; It is particularly poignant to note that eighty-five per cent of patients who do get syphilis but who are untreated will have an entirely normal life span and seventy per cent of such patients will have no evidence of the disease when they die.

Sadly, the available evidence suggests that most doctors still don't understand the significance of obtaining false positives.

In April 1979 the Lancet published a paper entitled 'The Value of Diagnostic Tests' which reported that when doctors and medical students were asked to interpret a simple statistical problem most of them got it badly wrong. The question was: 'If a test to detect a disease, which affects one in 1,000, has a false positive rate of five per cent, what is the chance that a person found to have a positive result actually has the disease?' Out of sixty professionals who were asked this question twenty-seven answered ninety-five per cent while eighteen answered two per cent.

This means that little more than a quarter of those questioned understood the principles of basic statistics. The correct answer should have been that one person out of the 1,000 can be assumed to have the disease. Therefore 999 people will not have the disease, but five per cent of these, or roughly fifty, will give a false positive result. Consequently only one out of fifty-one people with a positive result will actually have the disease.

This sort of statistical analysis of investigations may seem to be only of academic value. But in practice such anomalies are extremely important.

Most doctors regard laboratory tests as invariably accurate. When the results come back from the laboratory, they are regarded with the sort of reverence once accorded to messages on tablets of stone. But the plain fact is that most laboratory tests are only ninety-five per cent accurate - even when all the equipment in the laboratory is working absolutely perfectly (something that usually happens about once a week). As a general rule ninety per cent accuracy is more likely. So, if a patient has twenty laboratory tests done (a figure that is probably fairly accurate these days) then the chances are that even if he is perfectly healthy the tests will show at least one abnormality. And that is when the trouble starts.

When doctors spot an abnormality then they think in terms of disease. And when they think of disease they think in terms of treatment. The treatment involved will, of course, depend upon the false positive that has been obtained. But from this simple example it is easy to see that just about every patient going into hospital will have a good chance of being treated for a disease he hasn't got. Indeed, simply having the diagnosis made can sometimes change a patient's life. One recent study showed that out of ninety-three children who had been diagnosed as having heart disease – and who had lived as 'heart patients' – only seventeen really had heart disease.

So far I've dealt largely with laboratory tests and investigations. But ever since Rontgen first discovered X-rays at the end of the nineteenth century radiology has played an increasingly important part in the average doctor's investigative armamentarium. Go into hospital for a fairly routine operation and there is an excellent chance that they'll take at least one X-ray even if it's only a routine X-ray of your chest.

How much good do all these X-rays do? The answer, I'm afraid, is that most of them are entirely unnecessary. They are potentially hazardous, they are extremely expensive and they are extremely unlikely to contribute anything to your doctor's knowledge of your illness.

One of the first papers to have been published criticizing the number of X-rays done appeared in the British Medical Journal in November 1968 when a radiologist and a neurologist estimated that the consumption of X-ray film was doubling every thirteen years. Dr J. W. D. Bull and Dr K. J. Kilkha concluded that their study gave 'ample evidence that the great majority of plain X-ray films taken for such conditions as migraine and headache, did not contribute materially to the diagnosis.' They pointed out that much time and effort was wasted by doctors, radiographers, and patients. Their plea for doctors to think before ordering X-rays fell on deaf ears.

In 1975 the British Medical Journal again printed an appeal for doctors to order fewer X-ray pictures. By then it was estimated that the number of radiological examinations was increasing by ten per cent every year. This time the report in the BM] pointed out that after routine X-rays were taken of 521 patients under the age of twenty not one serious abnormality was detected. In all these patients chest X-rays were taken.

Once again doctors were asked to order fewer routine X-rays.

Once again the appeal was ignored.

By 1983 the problem had become such an important one (and such an international one) that the World Health Organization issued a statement saying that 'routine X-ray examinations frequently are not worthwhile. Doctors,' said the WHO, 'ask for X-rays as a comforting ritual.' The WHO report went on to point out that X-rays are so overused and misused that they constitute a major source of population exposure to manmade ionizing radiation. It also pointed out that X-rays account for between six per cent and ten per cent of a country's expenditure on health.

Since something like ninety per cent of all X-rays are unnecessary it is clear that between five per cent and nine per cent of Britain's expenditure on the NHS could be saved simply by finding some way to stop doctors ordering useless X-rays.

But the evidence suggests that little has changed and that doctors are still wasting just as much time, money, and energy as ever. In March 1987, for example, Nottingham medical school lecturer Dr Jim McCracken reported on a study he had co-ordinated into the treatment of pneumonia in general practice. McCracken concluded that it simply is not worth carrying out routine X-rays on recovered patients who have no clinical abnormality. It seems unlikely that this report will have any greater effect on the number of unnecessary X-rays being ordered than did the report written by Professor James Bull back in 1968.

NOTE
This essay is taken from The Health Scandal by Vernon Coleman which was first published in 1988 and which is now available via the bookshop on www.vernoncoleman.com