introduction

Teikyo University Centre for Evidence-Based Medicine

→ Top page

Introduction of the Symposium

Eiji Yano

Contents

■Evaluation and Evidence-based Medicine

■Structure of the Symposium

■Original Concept of EBM

■RCT and Cochrane Collaboration

■Outcome Study

■EBM in British National Health Service

■Okinaga Visiting Professorship Lecture

■EBM in Clinical Medicine

■EBM and Preventive Medicine

■EBM and Health in the Population

■The Next Symposium

■Conclusion

Evaluation and Evidence-based Medicine

In the first Teikyo-Harvard Symposium held in 1994⁽¹⁾the importance of evaluation in health and medical care was emphasized. In this present symposium, evaluation turned to be the main theme.
In general in Japan, evaluation has not been properly treated as important. In the systematic cycle of action with Plan-Do-Check-Act, Check does not work. As a consequence, Act does not make much progress.
In the field of health and medical care, due to the aging population, changing the pattern of mortality and morbidity, and affluence of supply as well as cost containment in medical care, people's attitude toward medical care has been changed. Plan and Do at the supply side can no longer decide on their own. Providing scientific evidence through Check process is getting more and more indispensable. This is why people are concerned with Evidence-based Medicine (EBM), in these days.
There has not been a universally accepted Japanese word equivalent for EBM⁽²⁾ and the understanding of ordinary people in evidence in medicine is quite different from that of physicians. For example, the efficacy of a drug is precisely proved by randomized controlled trial (RCT) as discussed later. However, not many medical technologies have been proved for its scientific basis for their efficacy. One study showed that only 10 to 20 % of medical technologies commonly provided in daily clinical settings based on scientific evidence for their validity. In reality, most of the common medical technologies based on experiments in laboratories prove only the biochemical mechanisms leading to the belief of validity. In other instances, they are based on experiences under the logic of "used", "recovered" then "valid". These are not sufficient at all as a scientific basis for validity. However, ordinary people believe and expect that all the medical technologies based on sound scientific basis which prove the technologies effective to humans. Recent debate on the effectiveness of the drugs for dementia and prevention and treatment of cancer arose from the gap in belief of evidence between ordinary people and physicians.

→ contents

Structure of the Symposium⁽³⁾

The primary mission of this symposium is to comprehend the reality in medical practice that scientific basis of medical technology is insufficient. There we need to consider: what is evidence?, how to create it?, how to access it? The major part of the first day of the symposium was devoted to this point.
However, clinicians who devote most of their days in clinical practice feel that the above discussion on evidence is unrealistic. Therefore, keeping the real clinical settings in mind, the second day discussion focused on how to make daily clinical practice in accord with EBM, or at least, to shift toward EBM.
EBM originally started from clinical medicine, however, the concept of EBM has been expanded to preventive medicine, as well as the level of national and international issues related to health. Naturally, all patients and physicians are in the society that their activity and also in the restriction of society. Accordingly, the symposium dealt with the issues related to society and the nation. In the following, EBM of various dimensions was described in the order of the report presented in the symposium. Also, some additional explanations were given.

→ contents

Original Concept of EBM

At first Professor Sackett, the pioneer of this field, from clinical epidemiology to EBM gave the opening lecture on the original concept of EBM. He is the author of the book titled Evidence-based Medicine⁽⁴⁾, and he issues a periodical journal under the same title. His lecture was not only the general overview but also demonstrated the state-of-art of EBM in practice by giving an example performed in the teaching hospital of Oxford University. In the hospital, the Centre for Evidence-based Medicine is housed⁽⁵⁾.

→ contents

RCT and Cochrane Collaboration

After the general concept, 'how to get evidence' was discussed. For a clinician, when making a plan for treatment, the traditional way is to collect references and read them carefully and critically. Then, find the best evidence, or information found in the paper(s) with the highest reliability and validity⁽⁶⁾. From this point of view, results form RCT or randomized controlled trial will provide evidence. One may sum up information from several papers by using meta-analysis⁽^７).
However, for a busy clinician, it is not realistic to collect, read, and compare references for each patient when deciding the treatment plan. The purpose to read a reference is not to simply catch what is written but read critically and systematically and extract the most valid and appropriate information. To perform critical reading successfully, one requires a special training. In addition, the required information, in most cases, for the daily clinical practice is not special nor a huge variety. Therefore if the critical reading can be done systematically by well-trained persons and the results be distributed to the busy physicians, it should be extremely beneficial. This is why many academic societies of various medical fields form committees for major diseases and recommend guidelines for diagnosis and treatment for respective disease ⁽⁸⁾. The Cochrane Collaboration is on the same track but makes it more updated by revising it every three months using the latest information by RCT ⁽⁹⁾. The Cochrane Collaboration born in Britain is currently globalized and Dr. Gray who has made the greatest contribution in the process reported about it.

→ contents

Outcome Study

RCT, on which the Cochrane Collaboration is based, is performed in an ideal setting using the patients strictly selected to meet the indication of the treatment. The result measured in a RCT is efficacy of the treatment. On the other hand, in a real clinical setting patients may have various conditions other than the target disease, and the treatment itself may not be strictly performed under the required conditions. Hence, the results of the treatment may not be exactly the same as those obtained by RCT. Effectiveness of treatment is affected by many factors such as selection of treatment, appropriateness and timing of the procedure, coordination of the medical personnel and other issues related to process of the treatment ⁽¹⁰⁾. Of course, it is possible to measure the effect of the treatment process by RCT but it may not be clear which part of the process effects to what extent the results. To give the answer to these questions before the intervention study, descriptive study is required and that is why outcome studies under the usual circumstances of treatment are indispensable ⁽¹¹⁾. Among the many outcome studies launched so far, one of the largest is by Patient Outcomes Research Teams (PORTs)^（12）. By these outcome studies, it has been revealed that the maneuver of the operator, the general policy of the hospital, coordination of the co-medicals etc. can affect the results of operation. Dr. Barry reported about the outcome studies in the United States by taking prostatic diseases as an example.

→ contents

EBM in British National Health Service

Medicine is not only the issue of health and diseases but also the issue of the total life of the patients. Therefore, the results of medicine will be evaluated in the whole life of the patients. Moreover, medicine is not the matter between a doctor and a patient but the matter in the whole society. As a consequence, evaluation of the outcome of medicine will deal beyond the level of the individual patient and to the level of population and society. Prevalence and mortality of the population, life expectancy and proportion of disabled are the examples of the evaluation index at the level beyond the individual. In addition, utilization of hospital beds, medical expenditure per capita and medical expenditure per GNP are other examples of outcomes evaluated in EBM.
It is very natural that the Cochrane Collaboration was launched in Britain where scientific basis for medical practice has long been pursued. EBM in Britain is not restricted to clinical practice but decision making and resource allocation in health policy. These are important elements of EBM in Britain. Professor Himsworth who is in charge of research and development in a regional office of the National Health Service reported the experience of Evidence Based Health Policy in Britain⁽¹³⁾.

→ contents

Okinaga Visiting Professorship Lecture

At the end of the first day program of the symposium, Okinaga Visiting Professorship Lecture was given ^（14）. The Okinaga Visiting Professorship in Harvard 1998 was given to Dr. Shigeaki Hinohara, president of the St Luke's Hospital in Tokyo. It was very timely to have his lecture in the symposium because Dr. Hinohara devoted his life to improve medical practice in Japan and also is one of the pioneers introducing the concept of EBM into Japanese medical society.

→ contents

EBM in Clinical Medicine

The second day of the symposium discussed the problems needed to overcome when EBM is applied and performed in making decisions in the actual settings of health and medicine. The areas to apply EBM are: clinical practice, preventive medicine and health policy. At first, Dr. Hashimoto, a Teikyo Faculty who was studying in Harvard summarized the first day discussion and then talked about the limitations of the outcome study.
Professor Doba, using cardiovascular diseases as examples, discussed the problems and difficulty in performing medical practice following EBM principle. In Japan, there have been traditional ways of practicing medicine. Also, major causes of mortality and morbidity are different from those in Europe and North America as shown by low incidence of ischemic heart diseases. These factors naturally lead to a different approach in performing EBM in Japan. Also discussed by Professor Doba was the emphasis on the importance of education and how to teach EBM in medical education.
In developing and disseminating EBM, evaluation of daily clinical practice and also application of clinical guidelines to the clinical practice are extremely beneficial apart from the studies specially designed for the evaluation. For this purpose, information technology in hospitals plays a key role. Computers in hospitals were first used for accounting, but now computers are highly utilized for the clinical processes of diagnosis and treatment. This opens a possibility for systematic information gathering from actual clinical practice. However, for the systematic collection of clinical information, structured medical information systems should be developed and clinical practice itself should be standardized. Critical pass is a key methodology for this purpose⁽¹⁵⁾.
Treat patients following guidelines or critical pass, then evaluate the outcome by scientific procedure. When a problem is found, the fundamental cause should be sought and improvement of the treatment made. These processes are continuous cycles for the improvement of clinical practice and an application of Continuous Quality Improvement developed and commonly practiced in the business world ⁽¹⁶⁾. Dr. Bates described the experience of the development of medical information systems in the Brigham and Women's Hospital, Harvard University and discussed the mutual progress by interaction between medical information and EBM.
Also, in the studies of this kind, the results depend very much on case-mix⁽¹⁷⁾ or composition of patients. Consequently, standardization of the severity of patients has been considered. APACHE is one of its kinds and Dr. Tajimi, from the Critical Care Center of Teikyo University discussed the necessity of EBM by using APACHE and contrasting the emergency care systems in the US and Japan.

→ contents

EBM and Preventive Medicine

The second afternoon of the symposium was started with the topics of preventive medicine. In Japan, secondary prevention or screening is so widely and extensively performed that preventive medicine is nearly a synonym for health check-ups ⁽¹⁸⁾. However, as Geoffrey Rose pointed out, traditional approach of early detection and treatment by screening (high-risk approach) may overlook the structural factors which decide the fundamental health status of the whole population ⁽¹⁹⁾. The high-risk approach can detect only those deviated within the population but cannot detect the deviation as a whole. On the contrary, the other approach called population approach, deals with the problems of the population. Professor Kay-Tee Khaw who has worked with Rose in the mass survey of WHO on stroke and osteoporosis talked about the population approach in preventive medicine.
In the United States, preventive practices such as smoking cessation program, health education on diet and exercise are evaluated by a systematic review of the literatures and the results were reported by a task force ⁽²⁰⁾. In the report, the quality of evidence was quantitatively evaluated and recommendations to perform or not to perform were given with rated scale. Professor Christiani, who participated in the task force, described the report by taking examples from occupational health, which was followed by the presentation of Professor Yano who evaluated the regular health check-ups in the workplace in Japan.

→ contents

EBM and Health in the Population

The last session of the symposium discussed EBM in health policies and targeted nations and the world. Most effective allocation of the limited resources could be guided by evidences obtained by economic analysis. To measure health in the population and demonstrate it by simple indices is essential for this process. For this purpose, classical indices based on death events such as infant mortality and life expectancy are no longer appropriate to tackle with the current health problems which are characterized by chronic diseases, aging, and highly industrialized society. Recently, new health indices, which take disability into account, have been proposed. Dr. Nonaka gave an overview of them and discussed the longevity and quality of life. Dr. Lopez who developed with Professor Murray the concept of Disability Adjusted Life Years (DALY)⁽²¹⁾ talked about it and its potential to assess health problems in nations, regions, and the whole world by quantifying the impact of disease and disability.

→ contents

The Next Symposium

At the very end of the symposium, Professor Brain summarized the symposium and announced the plan of the fourth symposium, which will discuss aging and health to be held in Boston in the year 2000.

→ contents

Conclusion

As can be seen, this symposium dealt with EBM and the wide variety of dimensions related to health and medical care, starting from clinical practice for an individual patient to the impact of disease in the world. EBM is not merely a concept but a practical strategy that the actual practice is most important. There are a number of obstacles before we can realize EBM and we should not be too optimistic. Therefore, we need to start EBM by evaluating our daily activity in health and medical care. I hope that the symposium and this book can help these activities.

→ contents

Footnotes

(1) The First Teikyo-Harvard Symposium

On 22 and 23, October, 1994 the first Teikyo-Harvard Symposium was held at the University of United Nations in Tokyo. The theme was "Environment, Health and Medical Care for the 21^st Century." Like the following symposium, there participated the delegation from Cambridge University and Oxford University in addition to those of Teikyo University and Harvard University. There were four sessions regarding health policy, environment, aging and occupational health. In concluding the first symposium, the chairman of the symposium emphasized the importance of evaluation as well as that of prevention, research, education and coordination for the 21^st century. The report of the first symposium was published from the University Publisher, Harvard University in 1995 under the same title of the symposium.