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Evidence-based medicine – between magic formula and a doctor's strait jacket

Evidence-based medicine revolves around the principle that doctors only use medications and therapies whose efficacy and usefulness has been reliably proven in scientific studies. The idea behind evidence-based medicine is to improve the quality of medical treatment as well as enable the more rational usage of limited resources in the healthcare sector. However, not all doctors have the time and statistical knowledge to be able to adequately judge the quality of scientific studies. In addition, many critics believe that evidence-based medicine has methodological limits in numerous indications. Nevertheless, many health authorities now base their decisions on this new concept.

Up until the 1990s, it was recommended that newborn babies slept on their stomachs. The advocate of this sleeping position was American paediatrician Dr. Benjamin Spock. In his 1958 book “Baby and Child Care”, which is still one of the international all-time bestsellers, Dr. Spock argued that “if [an infant] vomits, he’s more likely to choke on the vomitus when placed on the back when sleeping.” This theory-based argument has been unanimously adopted by many paediatricians over the years. However, no empirical studies were undertaken to prove Spock’s recommendations.

The methodological quality of medical studies is characterised by the quality of medical evidence and the strength of recommendation. © P. Bottermann, MMW-Fortschr. Med. No.4/2006
Later empirical studies have shown that there is a significantly increased risk of sudden infant death syndrome when infants sleep on their stomachs. The first evidence for this was collected in 1970, but it was not until the 1990s following alarming results obtained in these studies that the recommendation was made to place babies on their back to sleep. The incidence of sudden infant death subsequently decreased by more than 50 per cent within a very short time in a number of industrial countries. Advocates of evidence-based medicine have used this as a prime example of the importance of basing healthcare recommendations on statistical evidence. If a systematic analysis of the available empirical data on sleeping positions had been carried out in the 1970s, experts estimate that as many as 50,000 infant deaths could have been prevented had Spock’s advice been changed.

Gold standard of epidemiologists

The British epidemiologist Professor Archibald Cochrane referred to the importance of randomised controlled studies in healthcare in his book “Effectiveness and Efficiency: Random Reflections on Health Services” published in 1972. Randomised controlled studies have since become the gold standard in assessing the efficacy of medical therapies. However, it was not until 1996 that a group of clinicians and clinical epidemiologists led by David Sackett at the Canadian McMaster University contributed to the breakthrough of the concept of evidence-based medicine.

The objective of advocates of the concept of evidence-based medicine is that doctors should only be allowed to prescribe scientifically proven medications and therapies. Experts expect that this concept will not only lead to an improvement in the quality of treatment, but also to a reduction of costs in the healthcare sector because numerous therapies that have been shown to have no effect will cease to be used. Many people see evidence-based medicine as a kind of magic formula when it comes to assessing the best medications and therapies currently available.

Scientific facts

© BIOPRO

However, the quantity of medical papers published has been increasing exponentially over the last few years. More than 10,000 journals and over 2,000,000 medical articles as well as 10,000 randomised controlled studies carried out every year are an insurmountable obstacle for individual doctors or scientists. The "half-life of knowledge" in the field of medicine is only around five years, and is decreasing continuously. In practice this means that the need for comprehensively summarised and reliably assessed information is therefore gaining in importance.

The "Cochrane Collaboration", which was established in 1993, is focusing on this need. It is an independent international network of scientists and doctors who attempt to analyse and evaluate all medical studies relating to a certain health problem. The methodological quality of the studies is characterised by so-called "evidence degrees". The Cochrane Collaboration has become a leader in the preparation of systematic reviews and meta-analyses, providing medical associations with the scientific facts needed to prepare evidence-based medical guidelines.

Doctors feel restricted in the freedom to select therapies

However, some doctors are less happy than others with the developments that have found their way into patient treatment as a result of evidence-based medicine. Many doctors feel that evidence-based medicine restricts their treatment and diagnosis options and such doctors refer to evidence-based medicine as a “strait jacket for doctors”. The problem becomes particularly apparent with patients suffering from diseases whose treatment has no class I proof of efficacy. This is particularly the case of rare diseases for which no study results from large patient collectives are available. Here, the critics of evidence-based medicine argue that more importance must be placed on doctors’ individual medical experience and expertise than on the requirement for external scientific evidence. This argument is one of the reasons why only 30 to 40 per cent of medical treatment is currently based on proven scientific evidence.

However, doctors can no longer completely ignore the concept of evidence-based medicine. Although the guidelines established by medical associations are not yet legally binding for doctors, evidence-based medicine already determines the guidelines for the healthcare services of statutory health insurance funds and the evaluation of medical research published by the most important health authorities and committees – for example the Joint Federal Committee of physicians, dentists, psychotherapists, hospitals and insurance funds in Germany. It seems that a standardised and scientifically founded procedure in the healthcare sector has become indispensable for guaranteeing quality healthcare services and cost efficiency.

sb - 8th Nov. 2010
© BIOPRO Baden-Württemberg GmbH

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