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Lies, damned lies, and evidence-based medicine
DISSECTING ROOM
JABS & JIBES
LIFELINE David Shaw David Shaw qualified at Charing Cross Hospital, and held training and research posts in the UK and USA. He is honorary physician and senior lecturer at Exeter University, UK. His interests are diagnostic pacemaker development with the Engineering School, Exeter, and sino-atrial dysfunction and atrioventricular block. Who was your most influential teacher? Tom Simpson, consultant physician at Chase Farm Hospital Enfield, showed me the value of very long followup in a relatively stable population—in his case patients with pulmonary emphysema. Which patient has had most effect on your work? A florid Westcountryman who had had chronic heart block for 10 years and led a very active life with the local hunt, but had been on the “Social” since the diagnosis was made. Obviously, he couldn’t be expected to work because he had “a blocked heart”. Clearly there were blocked hearts and blocked hearts, and I’ve been fascinated by the cardiac conduction system ever since. What or who is the greatest love of your life? My wife was in hospital when I met my greatest love. She was born in the bedroom cupboard, the tenth child of Jemima. On my wife’s return home with our new son, Jemima was dismissive, and transported my love and three other kittens onto our bed to establish precedence. How would you like to die? Suddenly, from ventricular fibrillation, or maybe sinus arrest with no escape rhythm might be appropriate. Preferably just before the alarm clock went off on the morning of a dental appointment. What is your favourite journey? 1958 Tripoli, and a visit to Leptis Magna and Sabratha. An Iraqi diplomat pressed an invitation to take my wife with him to Baghdad. I sometimes wonder . . . What is your worst habit? A hopeless memory, particularly for faces, I even drove past my newly wedded wife without recognition.
1824
Lies, damned lies, and evidence-based medicine he world is full of inflation. Inflated prices, inflated money, inflated academic egos, inflated expectations. In the late 1940s, the UK’s medical planners were confident that the introduction of a free health service without barrier at point of entry would ultimately reduce the need for health care. 50 years later, we may be witnessing a similar inflated hope—that patients at risk of receiving health care that is at best ineffectual and at worst harmful can receive care from a service underpinned by scientifically based evidence at every level. But no-one has tipped the glitterati of evidencebased medicine (EBM) the wink—that the basis of modern science is one of uncertainty; that we live in a chaotic system where thermodynamics and not mechanics are our guide and where changes over time are not reversible: different today from yesterday, different again tomorrow. As the British Medical Journal was dropped onto their doormats, little did doctors realise on that autumnal Saturday morning in 1948 that they were witnessing a momentous event. The first medical randomised control trial had appeared on the world scene, and a new era of medicine had begun. The experiment was quite straightforward. Patients with tuberculosis, unaware they were taking part in a clinical study, were randomised to receive streptomycin or nothing. With a plunge of a syringe, 3000 years of medical treatment based on experience and perceived effectiveness were at an end. Enter EBM and its ultimate instrument, the randomised controlled trial—“a thing of beauty”—set fair for rapid growth and rising like a phoenix from the observation of the large variation in clinical practice and health outcomes (findings that probably reflect the very confounding variables that randomised controlled trials seek to exclude). Now the essential truth without us could be discovered and our
T
interventions directed by explicit guidelines derived by rigorous inquiry. Evidence rules OK. Since the development of the steam engine in the late 18th century, economists have recognised 50-year cycles when critical technological innovation is introduced. Enter the computer and information technology. But compared with other fields of science and technology, the computer presented medicine with a seductive solution in search of a problem. EBM was quick to provide an answer, with the computer offering facilities for large amounts of storage and retrieval of data. No coincidence that the expansion of EBM has closely mirrored the power of the microcomputer. But does this cycle merely synthesise fools gold out of the base metal of medical publications? Decisions in life are based on a cognitive continuum. Wired to the cardiological bed, the heart disease succumbs to inferential statistics. But patients come and go: to the real world where attempts to impose a spurious rationality on an irrational process may not always succeed; where structures are highly complex and disease thresholds may not be met; where decisions are based on past experience, future expectations, and complex human inter-relationships; where doctors and patients have their own narratives; where time scales exceed those of the longest trial; and where the mechanisms of poverty are the greatest cause of dys-ease. Only a fool would deny the importance of evidence, but it may be wise at times of rapid change to proceed with circumspection—to adopt a pragmatic approach accepting the few things we know for certain, and learning to live with the uncertainty of most of the grey zones in medicine. Best perhaps to seek honesty, not truth. Caution rules OK. D P Kernick
THE LANCET • Vol 351 • June 13, 1998
JABS & JIBES
LIFELINE David Shaw David Shaw qualified at Charing Cross Hospital, and held training and research posts in the UK and USA. He is honorary physician and senior lecturer at Exeter University, UK. His interests are diagnostic pacemaker development with the Engineering School, Exeter, and sino-atrial dysfunction and atrioventricular block. Who was your most influential teacher? Tom Simpson, consultant physician at Chase Farm Hospital Enfield, showed me the value of very long followup in a relatively stable population—in his case patients with pulmonary emphysema. Which patient has had most effect on your work? A florid Westcountryman who had had chronic heart block for 10 years and led a very active life with the local hunt, but had been on the “Social” since the diagnosis was made. Obviously, he couldn’t be expected to work because he had “a blocked heart”. Clearly there were blocked hearts and blocked hearts, and I’ve been fascinated by the cardiac conduction system ever since. What or who is the greatest love of your life? My wife was in hospital when I met my greatest love. She was born in the bedroom cupboard, the tenth child of Jemima. On my wife’s return home with our new son, Jemima was dismissive, and transported my love and three other kittens onto our bed to establish precedence. How would you like to die? Suddenly, from ventricular fibrillation, or maybe sinus arrest with no escape rhythm might be appropriate. Preferably just before the alarm clock went off on the morning of a dental appointment. What is your favourite journey? 1958 Tripoli, and a visit to Leptis Magna and Sabratha. An Iraqi diplomat pressed an invitation to take my wife with him to Baghdad. I sometimes wonder . . . What is your worst habit? A hopeless memory, particularly for faces, I even drove past my newly wedded wife without recognition.
1824
Lies, damned lies, and evidence-based medicine he world is full of inflation. Inflated prices, inflated money, inflated academic egos, inflated expectations. In the late 1940s, the UK’s medical planners were confident that the introduction of a free health service without barrier at point of entry would ultimately reduce the need for health care. 50 years later, we may be witnessing a similar inflated hope—that patients at risk of receiving health care that is at best ineffectual and at worst harmful can receive care from a service underpinned by scientifically based evidence at every level. But no-one has tipped the glitterati of evidencebased medicine (EBM) the wink—that the basis of modern science is one of uncertainty; that we live in a chaotic system where thermodynamics and not mechanics are our guide and where changes over time are not reversible: different today from yesterday, different again tomorrow. As the British Medical Journal was dropped onto their doormats, little did doctors realise on that autumnal Saturday morning in 1948 that they were witnessing a momentous event. The first medical randomised control trial had appeared on the world scene, and a new era of medicine had begun. The experiment was quite straightforward. Patients with tuberculosis, unaware they were taking part in a clinical study, were randomised to receive streptomycin or nothing. With a plunge of a syringe, 3000 years of medical treatment based on experience and perceived effectiveness were at an end. Enter EBM and its ultimate instrument, the randomised controlled trial—“a thing of beauty”—set fair for rapid growth and rising like a phoenix from the observation of the large variation in clinical practice and health outcomes (findings that probably reflect the very confounding variables that randomised controlled trials seek to exclude). Now the essential truth without us could be discovered and our
T
interventions directed by explicit guidelines derived by rigorous inquiry. Evidence rules OK. Since the development of the steam engine in the late 18th century, economists have recognised 50-year cycles when critical technological innovation is introduced. Enter the computer and information technology. But compared with other fields of science and technology, the computer presented medicine with a seductive solution in search of a problem. EBM was quick to provide an answer, with the computer offering facilities for large amounts of storage and retrieval of data. No coincidence that the expansion of EBM has closely mirrored the power of the microcomputer. But does this cycle merely synthesise fools gold out of the base metal of medical publications? Decisions in life are based on a cognitive continuum. Wired to the cardiological bed, the heart disease succumbs to inferential statistics. But patients come and go: to the real world where attempts to impose a spurious rationality on an irrational process may not always succeed; where structures are highly complex and disease thresholds may not be met; where decisions are based on past experience, future expectations, and complex human inter-relationships; where doctors and patients have their own narratives; where time scales exceed those of the longest trial; and where the mechanisms of poverty are the greatest cause of dys-ease. Only a fool would deny the importance of evidence, but it may be wise at times of rapid change to proceed with circumspection—to adopt a pragmatic approach accepting the few things we know for certain, and learning to live with the uncertainty of most of the grey zones in medicine. Best perhaps to seek honesty, not truth. Caution rules OK. D P Kernick
THE LANCET • Vol 351 • June 13, 1998