BMJ VOLUME 306 3APRm 1993 - Europe PMC

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PHILIP BARLOW. Department of ... Thomas WEG, Shorthouse AJ, et al. Who's afraid of ... Altman (and indeed Philip Barlow) fail to differen- tiate between ...
surgical ward in the first place; furthermore, no steps were taken to ensure that they read and understood the detailed information given to them preoperatively.' More importantly, the evidence obtained in the study showed that providing only limited information to anxious patients resulted in a significant reduction in anxiety and that a quarter of those who received detailed descriptions (the quarter who actually understood it?) thought that they had been given too much information. The study could therefore be interpreted as showing the opposite of what the authors claim. To suggest that providing written detailed risks of an operation just before it is performed might reduce the chances of litigation is naive and implies that the authors have a poor understanding of the laws of negligence. At present the legal position regarding consent for surgery in Britain is fairly clear; it has been expressed in the judgments in two landmark cases, Sidaway v the board of governors of Bethlem Royal Hospital in the House of Lords2 and, in Scotland, Moyes v Lothian Health Board.3 The law does not require that fully informed consent is obtained in all cases but does require material risks to be disclosed and that all patients' questions are answered truthfully. As a criterion for what constitutes a material risk the Bolam principle is applied, which, put simply, states that a doctor should act "in accordance with a practice accepted as proper by a body of responsible and skilled medical opinion" (Lord Diplock'). In other words, the medical profession is still allowed to set the standards not only for treatment but for disclosure ofinformation. If it can be shown that there are good clinical grounds for giving such detailed preoperative information to all patients, even those who do not want it, then this is a practice that should of course be incorporated into our routines. But to start such a practice for legal reasons, for fear of being sued, is not only bad medicine but runs a danger of becoming the norm. An unnecessary and possibly harmful practice then reaches the status of a perceived legal requirement, and the profession ends up effectively creating a noose with which it may be hung. PHILIP BARLOW

Department of Neurosurgery, Institute of Neurological Sciences, Southem General Hospital, Glasgow G51 4TF 1 Kerrigan DD, Thevasagayam RS, Woods TO, McWelch I, Thomas WEG, Shorthouse AJ, et al. Who's afraid of informed consent? BMJ 1993;306:298-300. (30 January.) 2 Sidaway v board of govemors of Bethlem Royal Hospital [1985] AC 871. 3 Moyes v Lothian Health Board [1990] SLT 444.

EDrTOR,-The law is far from silent on informed consent, and the notion that "allowing patients to make a fully informed decision about their treatment would generate an unnecessary and harmful degree of anxiety" is outdated.' The legal necessity for medical practitioners in the United Kingdom to provide informed consent was established in the English High Court in 1981; it differs from that in some American jurisdictions in that it retains the "therapeutic privilege" to withhold information detrimental to the health of the patiert. The form of consent required is defined by a professional standard, so in disputes doctors are judged according to the standard of their peers. That the courts feel uncomfortable in allowing the medical profession even this degree ofdiscretion is evident from study of several recent legal cases in Britain, most importantly Sidaway v Bethlem Royal Hospital's board of governors, in which Lord Donaldson warned that the law "could not stand idly by if the medical profession, by an excess of paternalism, denied their patients a real choice."2 The courts are warning the medical profession that

BMJ VOLUME 306

3APRm 1993

patients must be provided with the information necessary to enable a balanced judgment on whether to submit to treatment. All material risks must be disclosed, subject only to that strict doctrine of therapeutic privilege. There is no fixed incidence at which a complication of treatment must be disclosed. Several factors require consideration, including the frequency and seriousness of the complication and the patient's desire for information. The patient's desire for information is worthy of special consideration. In Rogers v Whittaker the court held that a surgeon had a duty to warn a patient, who had particularly requested information on any possible complications of eye surgery, of the one in 14000 risk of sympathetic ophthalmia leading to total blindness and that in not so warning her he had been negligent.' This Commonwealth case, though not binding on a court in the United Kingdom, is of

major importance. We do not have to disclose every possible complication of treatment to every patient. But we must disclose all those facts that we believe that a particular patient requires to make a true and balanced judgment on the merits of the treatment. D D Kerrigan and colleagues' study shows that patients are well able to weigh up the risks for themselves. JAMES BINGHAM Edinburgh EH3 6NB 1 Kerrigan DD, Thevasagayam RS, Woods TO, McWelch I, Thomas WEG, Shorthouse AJ, et al. Who's afraid of informed consent? BMJ 1993;306:298-300. (30January.) 2 Sidaway v Bethlem Royal Hospital Board of Govemors [1985] 1 All ER 643. 3 Rogers v Whittaker (SC NSW CA) 1992 Med LR 33 1.

AuTHoRs' REPLY,-J Martin Bland and Douglas G Altman's analyses support our two principal conclusions that (a) detailed preoperative information does not provoke a clinically significant increase in anxiety and (b) there is no relation between a patient's baseline anxiety score and the change in anxiety that occurs after detailed information is given. We believe that Bland and Altman (and indeed Philip Barlow) fail to differentiate between statistical and clinical significance, even though information to guide them was provided in the paper. Their case is based on two major statistical criticisms, both of which we dispute. Their first criticism was that we used each patient as his own control rather than comparing anxiety scores in patients who had received simple and detailed information. Our hypothesis was that providing patients with very detailed information might greatly increase anxiety; we did not test whether detailed information produced more anxiety than simple information. Consequently, we chose to highlight the clinically minor changes that occurred in the two groups individually, particularly because comparing anxiety in the same patient before and after information is given nullifies the many variables that might influence perioperative anxiety (previous surgery or complications in self or a relative, fears about hospitals and anaesthetics, etc). We did not draw any conclusions based on an indirect comparison of significance tests in the two groups but provided readers with information to make a direct comparison between groups without having to resort to the complicated analyses suggested by Bland and Altman (table II shows that the mean change in anxiety in each group falls outside the 95% confidence interval for the other group). Table II also shows that the mean anxiety score in those given detailed information exceeded that of the group given simple information by approximately 3 (the same figure that Bland and Altman arrive at), but what they have not appreciated is that the size of this statistically significant change is clinically miniscule. The power calculation summarised in the paper defines

a change in anxiety of at least 5 points on the Spielberger scale as clinically important, although even this response to a comprehensive list of operative complications hardly reflects a large increase when the potential change on this scale ranges from 0 to 60 points. We deliberately chose not to comment on the clinically insignificant difference between the two groups, preferring to concentrate on the estimated effects of each type of information sheet. The second criticism relates to our scatterplots and the Pearson correlation coefficient to illustrate the relation between baseline anxiety and change in anxiety. We believed that our choice of axes was the simplest way of presenting raw data to readers. Because we are aware that mathematical coupling occurs when change is correlated against baseline values our calculation of r was derived by comparing the change in anxiety with the mean of the two Spielberger scores (as stated in the methods). We accept that Blomqvist's alternative method may be technically superior; as Bland and Altman point out, however, its main disadvantage is its dependence on the assumed value of the test-retest correlation G. Bland and Altman use an estimate of G calculated from our data, and this concerns us; it is not possible to calculate G accurately when there has been an intervention (receiving the information sheet) between the test and retest. If a higher value of G is assumed (say 0 9) Blomqvist's method produces exactly the same conclusions as we report. Nevertheless, even when Bland and Altman's assumed value of 0 79 is used their conclusions serve only to emphasise our clinical conclusions because throughout the paper we advise readers to interpret the small (yet statistically significant) reduction in anxiety seen in those who had received simple information with cautionthat is, the clinical interpretation stated in the discussion is that there is no relation between baseline anxiety and the change in anxiety observed in either group. Barlow seems to have confused the main objective of the study-namely, to detect any acute change in anxiety that occurred after patients had received detailed or simple information. The fact that patients arrived on the ward hardly constitutes reliable evidence of informed consent. Furthermore, our principal conclusions are unaffected by what patients thought about the amount of information they had received (and three quarters of those who had received detailed information thought that the amount they had received was about right). We were aware of the importance of ensuring that patients read and understood the information we gave them and describe in our paper the steps we took to ensure this. Whether or not detailed preoperative counselling will reduce subsequent litigation was not the subject of our study but has been covered in James Bingham's lucid account. An exhaustive list of complications offers no protection for the inept clinician, but it acknowledges that medical accidents occur even in the best hands. Barlow seems to believe that providing patients with detailed information is "unnecessary and possibly harmful." How exactly could this practice be harmfulby making patients much more anxious (a notion disproved by our study) or by allowing a gradual erosion of the "clinical freedom" which keeps patients in the dark about the risks we ask them to take? Our study should not be overinterpreted as a desire for rigid regulation of the consent process but should stimulate discussion about whether doctors need to alter their preconceptions. We believe that the onus should be on the surgeon to prove that there are good grounds for not providing a particular patient with all the facts. DAVID KERRIGAN

Royal Oldham Hospital, Oldham OLI 2JH BRIAN FARAGHER

University Hospital ofSouth Manchester, Manchester

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