How does evidence based guidance influence determinations of medical negligence?
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《英国医生杂志》
1 School of Humanities, King's College, London WC2R 2LS brian.hurwitz@kcl.ac.uk
Introduction
Evidence is a generic notion of great importance to many practices and enquiries. Cardinal to spying, journalism, historical and scientific research, and the practice of medicine, semantically the term bundles together two approaches to supporting belief, perception, and understanding. Whether evidence refers to marks or indications conspicuous to an observer, to reasoning and judgment about such indications, or to analysis of data arising from experiments, evidence leads on to and supports hypotheses and conclusions, however provisional and conditional.
Evidence—and the more recently minted compound term "evidence based"—refers to reliable observational, inferential, or experimental information forming part of the grounds for upholding or rejecting claims or beliefs. Evidence based medicine (EBM) has not developed a new concept of evidence2; its major contribution lies in the emphasis it places on a hierarchy of evidential reliability, in which conclusions related to evidence from controlled experiments are accorded greater credibility than conclusions grounded in other sorts of evidence. Since studies underpinning most medical practices are generally of very variable design and quality—experimental, controlled, blinded or unblinded, uncontrolled, observational, ecological, cross sectional, prospective, retrospective, qualitative, and others—recommendations synthesised from such studies are themselves very variably related to evidence.
Summary points
The trustworthiness of clinical guidelines depends on marshalling and interpreting best evidence, which is usually of variable quality and credibility
A tension exists between descriptive tests of medical negligence anchored in customary practice and normative tests, which focus instead on what ought to be done
In the United Kingdom, the Bolam test has not yet been superseded by one that compares an allegedly negligent practice with a medical standard fashioned without reference to a responsible body of practising medical practitioners
Evidence based standards will almost always be Bolam defensible, although some US courts have indicated that slavish compliance with evidence based guidance could be considered substandard, where patients are foreseeably harmed as a consequence
Guidelines do not actually set legal standards for clinical care, but they provide the courts with a benchmark by which to judge clinical conduct
Evidence based guidelines claim to be authoritative in the sense of embodying a combination of best evidence and judgment, designed to ensure that recommendations are valid and reliable. For guidance to be binding on clinicians it must be trustworthy.3 But how trustworthy, clinically, can such guidance actually be? Take, for example, the 2003 UK evidence based guidelines for the management of asthma, which recommend intravenous infusion of 1.2 g of magnesium sulfate over 20 minutes for the treatment of severe life threatening asthma (level 1++ evidence and grade A recommendation).4 The Drug and Therapeutics Bulletin recently systematically reviewed the value of this treatment and concluded: "The current British Guideline on the Management of Asthma, published jointly by the British Thoracic Society and the Scottish Intercollegiate Guideline Network suggests that a single intravenous dose of magnesium sulphate should be used for the treatment of patients with acute severe asthma. However, the available data are weak and conflicting and do not justify this unlicensed use of the drug."5
Box 1: Limitations of evidence based guidance that worry clinicians
"There is a fear that in the absence of evidence clearly applicable to the case in hand a clinician might be forced by guidelines to make use of evidence which is only doubtfully relevant, generated perhaps in a different grouping of patients in another country and some other time and using a similar but not identical treatment. This is... to use evidence in the manner of the fabled drunkard who searched under the street lamp for his door key because that is where the light was, even though he had dropped the key somewhere else."8 (J Grimley Evans, professor of geriatric medicine, University of Oxford, 1995.)
"The `correct' interpretation of clinical research rests largely on understanding the notion of validity. Although much effort—from both epidemiologists and editors—has been invested in the study of internal validity, comparatively little progress has been made in defining criteria for external validity (generalizability ). The applicability of research data beyond the study population depends on clinical judgment, an inherently slippery art, but an art nonetheless."9 (R Horton, editor of the Lancet, 1995.)
"The extent to which guidelines depend on opinion is disturbing for anyone who believes they should be evidence-based. Guidelines are evidence filtered through opinion. The opinion is crucial—but whose opinion should it be? The NICE committee is made up of a variety of experts in different disciplines who take specific advice from a small number of specialists in the relevant field. These specialists may or may not hold an opinion widely shared by their (equally expert) colleagues."10 (J Hampton, professor of cardiology, University of Nottingham, 2003.)
Clinical guidelines constantly face challenges from dissenting authoritative reinterpretation of existing evidence and from new, relevant evidence that was unavailable at the time the recommendations were developed. In addition, however evidence based the process of development may be, a guideline may not easily be applied to a particular patient's care (box 1). Clinical guidelines should therefore be understood to command only a provisional title to be believed. Nevertheless, the General Medical Council has announced that doctors should "normally follow guidelines,"6 and a leading UK barrister in health law has concluded that the effects of guidelines and evidence based medicine combined are that many areas of medicine and surgery, which attract the attention of civil litigators, are or will be governed by clinical guidelines. Increasingly, it will be possible to plead just one particular form of negligence: failing to follow guideline X.7
Box 2: What is negligence?
Medical negligence is a composite legal finding, comprising three essential elements. The person bringing the action, the complainant (formerly known as the plaintiff) must show that:
Firstly, the defendant doctor owed the complainant a duty of care
Secondly, the doctor breached this duty of care by failing to provide the required standard of medical care
Thirdly, this failure actually caused the plaintiff harm, a harm that was both foreseeable and reasonably avoidable
Evidence based guidelines could influence the manner in which the courts establish the second element.
Medical negligence
Guidelines are introduced into courts by expert witnesses as evidence of accepted and customary standards of care, but cannot, as yet, be introduced as a substitute for expert testimony. In court they are treated as hearsay evidence: the mere fact that a guideline exists can neither establish its authority nor support the view that in the circumstances before a court compliance with the guideline would be reasonable and non-compliance negligent. Yet in the United States a study has shown that guidelines play a relevant or pivotal part in the proof of negligence in 6-7% of malpractice actions.19
A high proportion of guidelines fall short of meeting quality markers (see box 6), so it is important to prevent poor guidelines from influencing legal standards. However, this very possibility may eventuate because the courts do not generally call experts in guideline methodology to assist them in assessing the robustness and quality of clinical guidelines cited.20
If the presumption is that courts should consult clinical guidelines because they reflect customary standards of care, then the authority of newly developed guidelines that make recommendations departing from usual practice would be diminished,22 as would guidelines motivated by cost cutting (see box 4). But if the presumption is that guidelines should be consulted by courts because they provide evidence of standards justified in relation to evidence rather than custom, this would radically strengthen the normative dynamic of the law in actions alleging medical negligence. It would also introduce a test of culpable fault much harder for defendants to meet than that represented by the Bolam test (even when modified by Bolitho23). The effect would be to propel medical compliance with—possibly slavish obedience to—clinical guidelines.
Box 5: Daniel Merenstein
Daniel Merenstein15 reports that while he was a resident on a training programme for family doctors in 1999, a 53 year old man consulted him for a routine health checkup. In the course of the consultation, Merenstein documented discussion of the importance of colon cancer screening, dental care, exercise, improved diet, sunscreen use, and prostate cancer screening. In conformity with the evidence based approach recommended by national clinical guidelines (including those of the American Academy of Family Physicians and the American Urological Association) for screening men over 50 years of age, he discussed the risks and benefits of prostate specific antigen (PSA) estimation, after which the patient elected not to have this measured. The patient later changed doctors and subsequently underwent PSA testing after no discussion of associated harms or benefits. His PSA concentration proved to be very high, the result of advanced prostate cancer (Gleason 8), and he subsequently brought an action against Merenstein and the residency training programme, alleging malpractice.
The nub of the patient's case was that he had been a victim of substandard care. His lawyers successfully argued that the standard of care to be expected when a man over 50 years consults a family doctor for a checkup in Virginia should include routine, PSA testing recommended by the doctor, rather than an offer of PSA estimation in the context of a shared decision making model, in which the patient makes an informed decision whether or not to undergo the test. Four doctors called as expert witnesses testified that, contrary to evidence based guidelines they themselves would not discuss the pros and cons of prostate cancer screening when consulting with men over 50 for health checks but would order a PSA test routinely. The jury seems to have accepted there were two schools of thought concerning responsible and proper practice in these circumstances as it exonerated Merenstein. However, it held the clinic where he worked liable in negligence.
At a time when only a tiny proportion of guidelines has been shown in rigorous trials to lead to better outcomes, such mass conversion by clinicians may not be desirable. Translating guideline standards into legal standards would tend to deny a role for judgment in using guidelines, which could lead to increased legal scrutiny of guidelines development procedures and their authorship processes.
Discussion
As we have seen, it is not beyond the bounds of possibility that, in very particular circumstances, adherence to evidence based guidance associated with harm to patients could be deemed inappropriate and even negligent by the courts, but such cases remain rare and have generally not set legal precedents.
Evidence based guidelines set normative standards such that departure from them may require some explanation, but they do not constitute a de facto legal standard of care. They take the finder of fact (judge in the United Kingdom, jury in the United States) to a very definite starting place—namely to justified, advocated medical standards—from which to make an assessment of questionable conduct, and this represents quite a departure for the process of adjudication hitherto adopted by the courts, which has relied almost exclusively on expert witnesses setting normative boundaries. Because bona fide guidelines carry a presumptive status that means clinicians should generally follow them and if not should take account of them, courts now have available to them the added information and wisdom that guidelines embody.
The bottom line so beloved of EBM readers is: guidelines do not actually set legal standards for clinical care but they do provide the courts with a benchmark by which to judge clinical conduct.
A longer version is on bmj.com
Acknowledgement: I thank Rory McDonagh, Richard Ashcroft, and Andrew Herxheimer for helpful discussion and commentary on an earlier draft of this paper.
Competing interests: BH is a member of the evidence based guideline development group of the National Collaborating Centre for Chronic Disease, which is developing clinical guidelines for Parkinson's disease for NICE.
References
Department of Health. Drug misuse and dependence—guidelines on clinical management. London: Department of Health, 1999: xv.
Straus SE, McAlister FA. Evidence-based medicine: a commentary on common criticisms. CMAJ 2000;153: 837
Raz J, ed. Authority. Oxford: Blackwell, 1984: 4, 115-41.
Scotttish Intercollegiate Guidelines Network, British Thoracic Society. British guideline on the management of asthma. Thorax 2003;58(suppl 1): i1-94.
Anonymous. Intravenous magnesium for acute asthma? Drug Ther Bull 2003;41:10: 79-80.
General Medical Council. Maintaining good medical practice. London: GMC, 1998: 4.
Foster C. Civil procedure, trial issues and clinical guidelines. In: Tingle J, Foster C, eds. Clinical guidelines: law, policy and practice. London: Cavendish, 2002: 111-20.
Grimley Evans J. Evidence-based and evidence-biased medicine. Age Ageing 1995;24: 461-3.
Horton R. Ann Intern Med 1995;123: 965.
Hampton JR. Guidelines—for the obedience of fools and the guidance of wise men? Clin Med 2003;3: 279-84.
Hucks v Cole ( 1960). Reported at 4 Med LR 393.
Texas & Pacific Railway ( 1903), 189 US: 468, 470.
Helling v Carey 519 Pacific Rep 2nd Series: 981-5
Albrighton v Royal Prince Alfred Hospital 2 NSWLR 542(CA), 562.
Merenstein D. Winners and losers. JAMA 2004;291: 15-6.
Bolam v Friern Hospital Management Committee 2 All ER 118-28.
Hurwitz B. Clinical guidelines and the law: negligence, discretion and judgment. Oxford: Radcliffe Medical Press, 1998.
Cranley v Medical Board of Western Australia (Sup Ct WA) 3 Med LR 94-113.
Hyams AL, Brandenburg JA, Lipsitz SR, Shapiro DW, Brennan TA. Practice guidelines and malpractice litigation: a two way street. Ann Intern Med 1995;122: 450-5.
McDonagh RJ, Hurwitz B. Lying in the bed we've made: reflections on some unintended consequences of clinical practice guidelines in the courts. J Obstet Gynaecol Can 2003:25: 139-43.
Grilli R, Magrini N, Penna A, Mura G, Liberati A. Practice guidelines developed by specialty societies: the need for a critical appraisal. Lancet 2000;355: 103-6.
MacNee W. Guidelines for chronic obstructive pulmonary disease. BMJ 2004;329: 111-20.
Bolitho v City and Hackney Health Authority 3 WLR 1151-61.
Hurwitz B. Clinical guidelines, NICE products and legal liability? In: Miles A, Hampton JR, Hurwitz B,eds. NICE, CHI and the NHS reforms: enabling excellence or imposing control? London: Aesculapius Medical Press, 2000: 151-60.
Samanta A, Samanta J, Gunn M. Legal considerations of clinical guidelines: will NICE make a difference? J R Soc Med 2003;96: 133-8.
Merenstein D. Evidence-based medicine on trial—reply. JAMA 2004;291: 1698
Mulrow CD, Lohr K. Proof and policy from medical research evidence. J Health Polit Policy Law 2001;26: 249-66.
Hall MA, Green MD, Hartz A. Evidence-based medicine on trial. JAMA 2004;291: 1697.(Brian Hurwitz, professor )
Introduction
Evidence is a generic notion of great importance to many practices and enquiries. Cardinal to spying, journalism, historical and scientific research, and the practice of medicine, semantically the term bundles together two approaches to supporting belief, perception, and understanding. Whether evidence refers to marks or indications conspicuous to an observer, to reasoning and judgment about such indications, or to analysis of data arising from experiments, evidence leads on to and supports hypotheses and conclusions, however provisional and conditional.
Evidence—and the more recently minted compound term "evidence based"—refers to reliable observational, inferential, or experimental information forming part of the grounds for upholding or rejecting claims or beliefs. Evidence based medicine (EBM) has not developed a new concept of evidence2; its major contribution lies in the emphasis it places on a hierarchy of evidential reliability, in which conclusions related to evidence from controlled experiments are accorded greater credibility than conclusions grounded in other sorts of evidence. Since studies underpinning most medical practices are generally of very variable design and quality—experimental, controlled, blinded or unblinded, uncontrolled, observational, ecological, cross sectional, prospective, retrospective, qualitative, and others—recommendations synthesised from such studies are themselves very variably related to evidence.
Summary points
The trustworthiness of clinical guidelines depends on marshalling and interpreting best evidence, which is usually of variable quality and credibility
A tension exists between descriptive tests of medical negligence anchored in customary practice and normative tests, which focus instead on what ought to be done
In the United Kingdom, the Bolam test has not yet been superseded by one that compares an allegedly negligent practice with a medical standard fashioned without reference to a responsible body of practising medical practitioners
Evidence based standards will almost always be Bolam defensible, although some US courts have indicated that slavish compliance with evidence based guidance could be considered substandard, where patients are foreseeably harmed as a consequence
Guidelines do not actually set legal standards for clinical care, but they provide the courts with a benchmark by which to judge clinical conduct
Evidence based guidelines claim to be authoritative in the sense of embodying a combination of best evidence and judgment, designed to ensure that recommendations are valid and reliable. For guidance to be binding on clinicians it must be trustworthy.3 But how trustworthy, clinically, can such guidance actually be? Take, for example, the 2003 UK evidence based guidelines for the management of asthma, which recommend intravenous infusion of 1.2 g of magnesium sulfate over 20 minutes for the treatment of severe life threatening asthma (level 1++ evidence and grade A recommendation).4 The Drug and Therapeutics Bulletin recently systematically reviewed the value of this treatment and concluded: "The current British Guideline on the Management of Asthma, published jointly by the British Thoracic Society and the Scottish Intercollegiate Guideline Network suggests that a single intravenous dose of magnesium sulphate should be used for the treatment of patients with acute severe asthma. However, the available data are weak and conflicting and do not justify this unlicensed use of the drug."5
Box 1: Limitations of evidence based guidance that worry clinicians
"There is a fear that in the absence of evidence clearly applicable to the case in hand a clinician might be forced by guidelines to make use of evidence which is only doubtfully relevant, generated perhaps in a different grouping of patients in another country and some other time and using a similar but not identical treatment. This is... to use evidence in the manner of the fabled drunkard who searched under the street lamp for his door key because that is where the light was, even though he had dropped the key somewhere else."8 (J Grimley Evans, professor of geriatric medicine, University of Oxford, 1995.)
"The `correct' interpretation of clinical research rests largely on understanding the notion of validity. Although much effort—from both epidemiologists and editors—has been invested in the study of internal validity, comparatively little progress has been made in defining criteria for external validity (generalizability ). The applicability of research data beyond the study population depends on clinical judgment, an inherently slippery art, but an art nonetheless."9 (R Horton, editor of the Lancet, 1995.)
"The extent to which guidelines depend on opinion is disturbing for anyone who believes they should be evidence-based. Guidelines are evidence filtered through opinion. The opinion is crucial—but whose opinion should it be? The NICE committee is made up of a variety of experts in different disciplines who take specific advice from a small number of specialists in the relevant field. These specialists may or may not hold an opinion widely shared by their (equally expert) colleagues."10 (J Hampton, professor of cardiology, University of Nottingham, 2003.)
Clinical guidelines constantly face challenges from dissenting authoritative reinterpretation of existing evidence and from new, relevant evidence that was unavailable at the time the recommendations were developed. In addition, however evidence based the process of development may be, a guideline may not easily be applied to a particular patient's care (box 1). Clinical guidelines should therefore be understood to command only a provisional title to be believed. Nevertheless, the General Medical Council has announced that doctors should "normally follow guidelines,"6 and a leading UK barrister in health law has concluded that the effects of guidelines and evidence based medicine combined are that many areas of medicine and surgery, which attract the attention of civil litigators, are or will be governed by clinical guidelines. Increasingly, it will be possible to plead just one particular form of negligence: failing to follow guideline X.7
Box 2: What is negligence?
Medical negligence is a composite legal finding, comprising three essential elements. The person bringing the action, the complainant (formerly known as the plaintiff) must show that:
Firstly, the defendant doctor owed the complainant a duty of care
Secondly, the doctor breached this duty of care by failing to provide the required standard of medical care
Thirdly, this failure actually caused the plaintiff harm, a harm that was both foreseeable and reasonably avoidable
Evidence based guidelines could influence the manner in which the courts establish the second element.
Medical negligence
Guidelines are introduced into courts by expert witnesses as evidence of accepted and customary standards of care, but cannot, as yet, be introduced as a substitute for expert testimony. In court they are treated as hearsay evidence: the mere fact that a guideline exists can neither establish its authority nor support the view that in the circumstances before a court compliance with the guideline would be reasonable and non-compliance negligent. Yet in the United States a study has shown that guidelines play a relevant or pivotal part in the proof of negligence in 6-7% of malpractice actions.19
A high proportion of guidelines fall short of meeting quality markers (see box 6), so it is important to prevent poor guidelines from influencing legal standards. However, this very possibility may eventuate because the courts do not generally call experts in guideline methodology to assist them in assessing the robustness and quality of clinical guidelines cited.20
If the presumption is that courts should consult clinical guidelines because they reflect customary standards of care, then the authority of newly developed guidelines that make recommendations departing from usual practice would be diminished,22 as would guidelines motivated by cost cutting (see box 4). But if the presumption is that guidelines should be consulted by courts because they provide evidence of standards justified in relation to evidence rather than custom, this would radically strengthen the normative dynamic of the law in actions alleging medical negligence. It would also introduce a test of culpable fault much harder for defendants to meet than that represented by the Bolam test (even when modified by Bolitho23). The effect would be to propel medical compliance with—possibly slavish obedience to—clinical guidelines.
Box 5: Daniel Merenstein
Daniel Merenstein15 reports that while he was a resident on a training programme for family doctors in 1999, a 53 year old man consulted him for a routine health checkup. In the course of the consultation, Merenstein documented discussion of the importance of colon cancer screening, dental care, exercise, improved diet, sunscreen use, and prostate cancer screening. In conformity with the evidence based approach recommended by national clinical guidelines (including those of the American Academy of Family Physicians and the American Urological Association) for screening men over 50 years of age, he discussed the risks and benefits of prostate specific antigen (PSA) estimation, after which the patient elected not to have this measured. The patient later changed doctors and subsequently underwent PSA testing after no discussion of associated harms or benefits. His PSA concentration proved to be very high, the result of advanced prostate cancer (Gleason 8), and he subsequently brought an action against Merenstein and the residency training programme, alleging malpractice.
The nub of the patient's case was that he had been a victim of substandard care. His lawyers successfully argued that the standard of care to be expected when a man over 50 years consults a family doctor for a checkup in Virginia should include routine, PSA testing recommended by the doctor, rather than an offer of PSA estimation in the context of a shared decision making model, in which the patient makes an informed decision whether or not to undergo the test. Four doctors called as expert witnesses testified that, contrary to evidence based guidelines they themselves would not discuss the pros and cons of prostate cancer screening when consulting with men over 50 for health checks but would order a PSA test routinely. The jury seems to have accepted there were two schools of thought concerning responsible and proper practice in these circumstances as it exonerated Merenstein. However, it held the clinic where he worked liable in negligence.
At a time when only a tiny proportion of guidelines has been shown in rigorous trials to lead to better outcomes, such mass conversion by clinicians may not be desirable. Translating guideline standards into legal standards would tend to deny a role for judgment in using guidelines, which could lead to increased legal scrutiny of guidelines development procedures and their authorship processes.
Discussion
As we have seen, it is not beyond the bounds of possibility that, in very particular circumstances, adherence to evidence based guidance associated with harm to patients could be deemed inappropriate and even negligent by the courts, but such cases remain rare and have generally not set legal precedents.
Evidence based guidelines set normative standards such that departure from them may require some explanation, but they do not constitute a de facto legal standard of care. They take the finder of fact (judge in the United Kingdom, jury in the United States) to a very definite starting place—namely to justified, advocated medical standards—from which to make an assessment of questionable conduct, and this represents quite a departure for the process of adjudication hitherto adopted by the courts, which has relied almost exclusively on expert witnesses setting normative boundaries. Because bona fide guidelines carry a presumptive status that means clinicians should generally follow them and if not should take account of them, courts now have available to them the added information and wisdom that guidelines embody.
The bottom line so beloved of EBM readers is: guidelines do not actually set legal standards for clinical care but they do provide the courts with a benchmark by which to judge clinical conduct.
A longer version is on bmj.com
Acknowledgement: I thank Rory McDonagh, Richard Ashcroft, and Andrew Herxheimer for helpful discussion and commentary on an earlier draft of this paper.
Competing interests: BH is a member of the evidence based guideline development group of the National Collaborating Centre for Chronic Disease, which is developing clinical guidelines for Parkinson's disease for NICE.
References
Department of Health. Drug misuse and dependence—guidelines on clinical management. London: Department of Health, 1999: xv.
Straus SE, McAlister FA. Evidence-based medicine: a commentary on common criticisms. CMAJ 2000;153: 837
Raz J, ed. Authority. Oxford: Blackwell, 1984: 4, 115-41.
Scotttish Intercollegiate Guidelines Network, British Thoracic Society. British guideline on the management of asthma. Thorax 2003;58(suppl 1): i1-94.
Anonymous. Intravenous magnesium for acute asthma? Drug Ther Bull 2003;41:10: 79-80.
General Medical Council. Maintaining good medical practice. London: GMC, 1998: 4.
Foster C. Civil procedure, trial issues and clinical guidelines. In: Tingle J, Foster C, eds. Clinical guidelines: law, policy and practice. London: Cavendish, 2002: 111-20.
Grimley Evans J. Evidence-based and evidence-biased medicine. Age Ageing 1995;24: 461-3.
Horton R. Ann Intern Med 1995;123: 965.
Hampton JR. Guidelines—for the obedience of fools and the guidance of wise men? Clin Med 2003;3: 279-84.
Hucks v Cole ( 1960). Reported at 4 Med LR 393.
Texas & Pacific Railway ( 1903), 189 US: 468, 470.
Helling v Carey 519 Pacific Rep 2nd Series: 981-5
Albrighton v Royal Prince Alfred Hospital 2 NSWLR 542(CA), 562.
Merenstein D. Winners and losers. JAMA 2004;291: 15-6.
Bolam v Friern Hospital Management Committee 2 All ER 118-28.
Hurwitz B. Clinical guidelines and the law: negligence, discretion and judgment. Oxford: Radcliffe Medical Press, 1998.
Cranley v Medical Board of Western Australia (Sup Ct WA) 3 Med LR 94-113.
Hyams AL, Brandenburg JA, Lipsitz SR, Shapiro DW, Brennan TA. Practice guidelines and malpractice litigation: a two way street. Ann Intern Med 1995;122: 450-5.
McDonagh RJ, Hurwitz B. Lying in the bed we've made: reflections on some unintended consequences of clinical practice guidelines in the courts. J Obstet Gynaecol Can 2003:25: 139-43.
Grilli R, Magrini N, Penna A, Mura G, Liberati A. Practice guidelines developed by specialty societies: the need for a critical appraisal. Lancet 2000;355: 103-6.
MacNee W. Guidelines for chronic obstructive pulmonary disease. BMJ 2004;329: 111-20.
Bolitho v City and Hackney Health Authority 3 WLR 1151-61.
Hurwitz B. Clinical guidelines, NICE products and legal liability? In: Miles A, Hampton JR, Hurwitz B,eds. NICE, CHI and the NHS reforms: enabling excellence or imposing control? London: Aesculapius Medical Press, 2000: 151-60.
Samanta A, Samanta J, Gunn M. Legal considerations of clinical guidelines: will NICE make a difference? J R Soc Med 2003;96: 133-8.
Merenstein D. Evidence-based medicine on trial—reply. JAMA 2004;291: 1698
Mulrow CD, Lohr K. Proof and policy from medical research evidence. J Health Polit Policy Law 2001;26: 249-66.
Hall MA, Green MD, Hartz A. Evidence-based medicine on trial. JAMA 2004;291: 1697.(Brian Hurwitz, professor )