1 Evidence-based obstetrics and gynaecology

1 Evidence-based obstetrics and gynaecology I N E Z E. C O O K E DAVID L. S A C K E T T

This chapter introduces obstetricians and gynaecologists to the concepts encompassed in evidence-based medicine and our need as clinicans to aspire to evidence-based practice. 'Evidence-based obstetrics and gynaecology' are words that engender enthusiasm, anger, ridicule or simple indifference among clinicians. Such a diversity of reaction is difficult to comprehend when one considers the aim of evidence-based practice: 'the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients ... the integration of individual clinical expertise with the best available external clinical evidence from systematic research' (Sackett et al, 1996). To offer our patients the care most appropriate to their needs is surely the aim of all involved in health care. The 'incensed' frequently maintain that their patients are already getting the best care and, understandably, do not like the inference that this may not always be the case. The 'indifferents' are convinced that there is no evidence for the majority of what we do in medical practice, so how can we contemplate basing our clinical decisions on that invisible/unavailable evidence? Even the enthusiasts admit that there are problems: the evidence may be out there somewhere, but how do we keep up with it?; where do we get the information?; how can we appraise the information we find?; how do we implement the evidence?; there is just no time available in a busy clinical practice. WHAT IS EVIDENCE-BASED PRACTICE? Good obstetricians and gynaecologists use both their individual clinical expertise and the best available external evidence when caring for their patients. A proficiency in extracting clinical signs and forming clinical judgement for an individual patient can only be acquired through clinical experience and clinical practice. It is only with that clinical expertise that the best external evidence can then be applied appropriately to an individual patient. Equally, without the best external evidence, clinical practice Bailli~re's Clinical Obstetrics and Gynaecology-Vol. 10, No. 4, December 1996 ISBN 0-7020-2260-8 0950-3501/96/040535 + 15 $12.00/00

535 Copyright © 1996, by Baillirre Tindall All rights of reproduction in any form reserved

536

1. E. COOKE AND D. L. SACKETT

risks becoming rapidly out of date, to the detriment of our patients. The practice of evidence-based obstetrics and gynaecology means integrating individual clinical expertise with the current best external evidence from systematic research. It results in an all-encompassing change to the way in which we continually add to our knowledge and integrate that information into the treatment of our patients. How does evidence-based medicine help us, and what is required from us, to achieve that goal? The practice of evidence-based obstetrics and gynaecology gives us the tools to direct our own learning throughout our clinical careers. The foundation of that learning will be the patients in our clinics, our ward rounds and our operating theatres: we can continue our medical education life long in the areas of clinical work that are important to us at that time. Professor Sackett summarizes these tools of evidence-based medicine as clinically important information about diagnosis, prognosis, therapy and other clinical health-care issues in which we identify the question, find the available evidence and then appraise and apply that evidence (Figure 1). 1. Convert these information needs into answerable questions; 2. track down, with maximum efficiency, the best evidence with which to answer them; 3. critically appraise that evidence for its validity (closeness to truth) and usefulness (clinical applicability); 4. apply the results of this appraisal in our clinical practice; and 5. evaluate our performance. Figure 1, Outline of the methods of evidence-based medicine. Reproduced from Sackett et al (in press, Evidence-based Medicine: How to Practise and Teach EBM. London: Churchill-Livingstone) with permission.

Clinical skills First, to practise evidence-based obstetrics and gynaecology involves no 'let-out' clause in developing as a clinician: gaining the clinical experience, clinical judgement, obstetrical and surgical skills vital to our daily work. Only if the correct history is taken, the correct diagnosis obtained, practical skills have been taught and learnt and the appropriate follow-up arranged can the effective treatment (medical or surgical) play its role. The thoughtful diagnostician also always has in his or her mind the patient's aim. What does this patient hope to achieve from her treatment? The outcome that is most important to patients may be far from the outcome that you, the clinician, are pitching at. Women with infertility and endometriosis receiving ovulation suppression as a treatment would be disappointed to discover that, while improving some of their symptoms, it will not improve their chances of a future pregnancy (Hughes et al, 1996). Following a history and examination, there are usually many decisions to be made: which tests, both clinical and diagnostic, will most efficiently give the diagnosis, which pointers are the best prognostic factors for the progression of the disease, what the best acute treatment is, or, if a longterm treatment, is needed, which would then be best. There may be one,

EVIDENCE-BASED OBSTETRICS AND GYNAECOLOGY

537

often more, of these decisions where the answer is uncertain in your mind. This gives an opportunity to track down the information for the next time, making it not a gap in your knowledge to be hidden, but a gap to be seized as an opportunity and filled (Richardson, in press). However, it is easy to go blindly looking for a topic in general. When a disease is new to you, that may be a reasonable way to begin your search. However, when we are repetitively dealing with the same clinical problems, the information we need is usually much more specific, whether we are dealing with a population or an individual.

The clinical problem: it all starts here A good question is both directly relevant to a patient problem and phrased in such a way as to elicit the precise answer. Learning to build a clinical question is a fundamental skill for evidence-based practice. With a little practice, you become adept at forming such simply articulated questions that not only focus the question in your own mind, making you think of the most clinically relevant points, but also focus the subsequent searching. This makes it a much more efficient use of time and effort and gives a framework for teaching evidence-based practice within our specialty. Scott Richardson describes the well-shaped clinical question as being a map with four specific landmarks (Figure 2) summarizing the population you are dealing with, the interventions under scrutiny and the particular outcome that is of importance to you and your patient(s). 1. 2. 3. 4.

The patient or problem being addressed. The intervention being considered. The comparison intervention, when relevant. The clinical outcome or outcomes of interest.

By intervention is meant a variety of events, including genetic conditions, environmental exposures, diagnostic strategies, the passage of time with a disease, clinical treatments and learning experiences. Figure 2. The well-formed clinical question can be built around four points. Reproduced from Sackett et al (in press, Evidence-based Medicine: How to Practise and Teach EBM. London: ChurchillLivingstone) with permission.

Examples of specific questions about the accuracy of a clinical finding, a prognostic factor, a diagnostic test, a treatment and prevention of future problems could be: • • •

In pregnant women, is measurement of the symphysis fundal height by tape measure better than clinical palpation at picking up the "small-fordates' fetus? In pregnant women, does standing for long periods at work increase the incidence of preterm labour? In women with post-menopausal bleeding, does an endometrial thickness measurement, by transvaginal ultrasound, of < 5 mm reduce the necessity for an endometrial biopsy?

538

I . E . COOKE AND D . L .

SACKETT

In preterm labour, can antenatal steroids reduce the incidence of intraventricular haemorrhage in the newborn? In women with premature prolonged rupture of the membranes at term, does a delay of augmentation of labour for 24 hours, as opposed to immediate augmentation, increase the incidence of emergency caesarean section? Already the wealth of opportunity offered by each patient you meet for continuing your education, and the education of those around you, becomes apparent. From one patient, you rapidly discover many potential questions. Trying to answer all the uncertainties for one patient, yet again, would leave you with a feeling that the task is insurmountable. When a problem has been dissected into a very specific question, it focuses your inquiry, thereby making the search for the evidence itself much more likely to bear fruit.

Critical appraisal The problem has arisen, the question is formed. Now the task is to find the best evidence, to appraise critically that evidence for both its validity (the methods) and its usefulness (converting the results into numbers that are clinically relevant, and assessing whether the results apply to your patient and her problem). The methods used to evaluate the data retrieved vary, depending on the type of question (reviews, therapy, diagnostic test, harm, guidelines, economic evaluation). Thus, each is dealt with in detail as a specific example in the forthcoming chapters. We as obstetricians axe particularly fortunate when it comes to finding the evidence because of the data that have already been collated and systematically reviewed in the Pregnancy and Childbirth Database over the past 20 years.

Implementation Finally, if the results are clinically important and also applicable to your population, how do you incorporate this new information into your armorial of knowledge and therapeutics when the same clinical problem arises again? Finding and assessing the evidence becomes a pointless exercise unless the information gained (whether it is the introduction of a new proven beneficial operative technique or the discontinuation of some common practice that is actually harmful) finds its way back to the patient and into your practice. Professor David Grimes and Professor Angela Coulter will give you their experience of how to implement both evidencebased medicine and the actual evidence that you unravel. Does this seem a lot of work? Well, we all know how little time we, in reality, put towards reading. If that time were directed towards finding the evidence for specific clinical problems that have appeared, and are likely to reappear, in routine work, surely that is time well spent, in comparison with flicking at random through the journals arriving on our doorstep. Even if a

EVIDENCE-BASED OBSTETRICS AND GYNAECOLOGY

539

clinician only manages this for one or two clinical questions a week, the resulting 50-100 new pieces of information collected over a year seem excellent ongoing education. The techniques behind evidence-based practice not only give you confidence to evaluate and reject or accept the written word, but also to assess the applicability of the results to your practice. W H A T EVIDENCE-BASED P R A C T I C E IS NOT Practising evidence-based obstetrics and gynaecology does not in any way replace or detract from individual clinical expertise: the proficiency, judgement and surgical skill that each of us gains only through observation and supervised practice in the clinic, in the delivery suite and in the operating theatre. Without this experience and diagnostic acumen, the best of evidence will be mishandled and ill used because of its inappropriateness for a particular mother/couple/fetus, 'It [evidence-based medicine] cannot result in slavish cook-book approaches to individual care' (Sackett et al, 1996). When applied to the correct clinical problem, evidence-based obstetrics and gynaecology can inform and enhance a particular clinician's performance with its resulting effect on the patient's outcome. It deters the good clinician from continuing with practices that are out of date and encourages the adoption of new proven interventions and diagnostic tests, all to the advantage of the patient. Evidence-based obstetrics and gynaecology is not a weapon for purchasers and fund holders to reduce expenditure by weeding out unnecessary and unhelpful tests and treatments. It is cost-effectiveness in the light of improved clinical outcome, which is the end-point, rather than cost reduction alone. In obstetrics and gynaecology, we aim to maximize the women's and children's quantity and quality of life. If that results in a less costly solution, all well and good, but the fact is that it is likely to raise rather than lower the cost of their care. Evidence-based obstetrics and gynaecology is neither impossible nor impractical. Audits of evidence-based practice in general medicine (Ellis et al, 1995), general practice (Gill et al, 1996) and psychiatry (Geddes et al, 1996) have shown not only that evidence-based practice is possible in busy clinical settings, but also that 80% of the patients received interventions that could be backed from the literature. Such studies show that busy clinicians who devote their scarce reading time to selective, efficient, patient-driven searching, appraisal and incorporation of the best available evidence can practise evidence-based medicine. Why then cannot obstetricians and gynaecologists follow suit? DO W E NEED EVIDENCE-BASED P R A C T I C E ?

Clinicians need new information with each patient they see. When asked to estimate how often they needed help, they estimated once or twice per

540

I. E. COOKE AND D. L. SACKETT

week. However, when shadowed as they actually saw patients, these same clinicians, on direct questioning, identified up to 16 needs for clinically important information in just one (half-day) session, a rate of about two questions for every three patients seen (Cavell et al, 1985). Where do we go at present for our information? Most of us report that we turn to our textbooks, regular journals or review articles (by which we usually mean traditional rather than systematic reviews) for that information. When actually shadowed, however, it is not our books but our colleagues at work to whom we turn for help in most instances. There are many reasons why we ask for the opinion of our seniors and more experienced clinicians. Most say that it is quicker to ask someone else than to look it up for ourselves: lack of time is a recurring problem in all facets of our work. Textbooks are frequently out of date both by the nature of paper, rather than electronic, publishing and because of the type of traditional review process usually included (Antman et al, 1992). Figure 3 is a cumulative meta-analysis of the effect of corticosteroids on respiratory distress syndrome in preterm infants. Significant benefit has been present since the first paper in 1972, yet a new textbook of obstetrics published in 1989 (Turnbull and Chamberlain, 1989) gave only one page (out of 1165) to discussing the pros and cons of steroids in preterm labour, with no recommendations about their use, and the author of another chapter stated that 'there is no convincing evidence of benefit' from the administration of corticosteroids. Others fell into the same trap at even later dates (Beckmann et al, 1992). This was the same year (1989) that Crowley showed a 30-50% reduction in respiratory distress syndrome when corticosteroids had been given to women at risk of preterm labour (Crowley et al, 1990). There are many instances in all specialties of ideas being propagated long beyond their usefulness and, in contrast, new and useful treatments not being introduced as efficiently as the evidence for their benefit has been produced. In our own specialty, we could consider our slowness to reject the dictum 'Once a section, always a section' (Cragin, 1916) or defer from a perineal shave for women in labour (Johnston and Sidall, 1922). 'the biases of eminent men are still biases' (Crichton, 1971) seems cruel, but 'the practice of evidence-based medicine provides clinicians with the skills to practise safe and effective obstetrics and gynaecology as practice evolves' (Grimes, 1995). It means that those in authority may find it difficult to accept that the junior members of the team may be able to assess and produce convincing evidence that will lead to changes of practice. It is also not enough to assume that prescribing treatments that theoretically should give a correct response, dependent on the presumed pathophysiology, will actually give the expected result. The example often quoted is that of the use of drugs to suppress cardiac arrhythmias in the post-infarction situation, which should theoretically lead to an improved outcome but actually increases the associated mortality (Echt et al, 1991). In other instances, the fact that treatments that should have worked in particular clinical settings have not done so has helped us to understand better the pathophysiology of a disease process. In the p.ast, diuretics and weight reduction were used to treat pre-eclampsia, assuming that the raised

EVIDENCE-BASED OBSTETRICS AND GYNAECOLOGY

541

blood pressure was similar to essential hypertension. Similarly the recent randomized controlled trial comparing phenytoin and diazepam against magnesium sulphate in the prevention of recurrent seizures in eclampsia has led clinicians to speculate that the seizures associated with eclampsia are mechanically different from the seizures of epilepsy (Eclampsia Trial Collaborative Group, 1995). When a keen group of general practitioners in Scotland were asked how much time they allocated to reading each week, the majority replied that it was about half an hour. When all grades of hospital doctor attending a grand round at the John Radcliffe Hospital in Oxford were asked the same question, they gave a remarkably similar answer (on average 30 minutes). Risk difference %, 95% C.I. 40 Year

No. of p~ie~s

1. Liggins

1972

1070

2. Block

1977

1200

3. Morrison

1978

1326

4. Taeusch

1979

1453

5. Papageorgiou

1979

1599

6. Doran

1980

1743

7. Schutte

1980

1864

8. Teramo

1980

1945

9. US Collaborative 1981

2688

Study

10. Schmidt

1984

2753

11. Morales

1986

2998

12. Gamsu

1989

3266

13. Carlan

1991

3290

14. Garite

1992

3372

15. Eronen

1993

3438

-30

-20

-10

i

i

i

+10

+20

r

j

,

0

,,

•

,,,,,,

Favours treatment

Favours control

Figure 3. Cumulative meta-analysis of corticosteroids. There has been a significant improvement in outcome of preterm infants from respiratory distress syndrome since 1972 (Liggins and Howie, 1972). Addition of results from randomized controlled trials reported since then have shown little change in the relative risk but, with increasing numbers within the treatment groups, the 95% confidence intervals have become narrower over past 25 years (Sinclair, 1995).

542

I . E . COOKE AND D . L . SACKETT

The pre-registration housemen reported spending the least time reading (75% had not allocated any reading time in the past week) but, interestingly, 40% of the consultants (the senior authorities whom we discovered above are the people we most frequently go to for advice) admitted that they too had not spent any time reading in the past week (Sackett et al, in press). As these questionnaires were both self-reported, and hence the time allocated likely to be overestimated, the message is clear: in a busy clinical week there is little time available to further our education. It is estimated that for a general physician, just to keep abreast of his orher specialty, he or she would have to read 19 articles per day 365 days of the year (Davidoff et al, 1995). How much more productive then to use that very scarce time for selective reading anchored on clinically relevant questions. The blind acceptance that what the doctor prescribes 'must be doing me good' is fast retreating; in most instances there is a welcome change in the doctor-patient relationship, allowing a more open discursive consultation but equally a situation that leaves the uninformed doctor feeling vulnerable. While the antagonists of evidence-based obstetrics and gynaecology are fearful that changes in our mode of practice are being forced upon them by purchasers, it is actually much more likely to be the inquisitive, well-informed consumer who will play an important role in manoeuvring clinicians to change their practice. In obstetrics, we are fortunate to have become accustomed already to taking on board the wishes of our consumers (Department of Health, 1993). Our mothers increasingly challenge us (obstetricians and midwives) to explain the evidence behind our decisions. Our aim is to do more good than harm. How often are we able to explain satisfactorily to ourselves, never mind our patients, where along the scale in Figures 3 and 4 a particular treatment we offer may fall?

!

Interventionoffers more good than harm

Even the best interventions may do harm

[ ~

Interventioncauses more harm than good

An ineffective intervention will do no good except for the placebo effect and may do harm

Figure 4. 'We hope our practice is based on treatments which lie to the left of this diagram but many of our interventions, at best, fall in the middle'. Reproduced from Gray (in press, Evidence-based Health Care. London: Churchill Livingstone) with permission.

EVIDE NCE-BASE D OBSTETRICS AND GYNAECOLOGY

543

HAVE OBSTETRICIANS AND GYNAECOLOGISTS SPECIAL REASONS TO PRACTISE EVIDENCE-BASED MEDICINE? Women attending a gynaecological clinic are like any other patient: they have a problem and are seeking help for that problem, be it heavy menstrual bleeding, reduced fertility or pelvic pain. Pregnant women are healthy when they first attend, and most will remain healthy throughout the process of pregnancy and delivery. While a few will start pregnancy with a specific problem and will accept our blanket surveillance techniques, the rest will enter the gigantic screening exercise that is our routine antenatal and intrapartum care in the hope that we are able to 'pick up' the few who will develop pathology. The problem of both inconveniencing and raising the anxiety levels of all, to identify the few who will benefit from our intervention, is an increasingly difficult balance, especially if one takes the viewpoint that the only successful screening test is one which identifies a problem for which we have a beneficial treatment (Enkin, in press). Archie Cochrane commented in 1972 regarding the failure of obstetricians and gynaecologists to evaluate the effectiveness of the care they instituted. His damning indictment did, however, lead to the database of systematic reviews on pregnancy and childbirth (Enkin et al, 1995a) being produced from the Oxford Database of Perinatal Trials (Chalmers, 1992). In 1979 Archie Cochrane commented that each specialty should have a critical summary of all randomized controlled trials relevant to its topic. The painstaking work of Iain Chalmers meant that in 1989 obstetrics was the first specialty to have such a registry of both trials and reviews. Now there are almost 9000 randomized controlled trials of perinatal care, which are, or have been, incorporated into over 600 systematic reviews of interventions used in antenatal and intrapartum care. These have been regularly updated and made available in either textbook (Chalmers et al, 1989; Enkin et al, 1995b) or electronic format (Cochrane Library, 1996). In his foreword to Effective Care in Pregnancy and Childbirth (Chalmers et al, 1989), Archie Cochrane withdrew his slur of the wooden spoon from obstetrics because of the effort and perseverance of the editors and reviewers involved in that project. However, gynaecologists are only beginning to apply the same rigorous evaluation to their care. The argument that surgical interventions cannot be evaluated by randomization is now being questioned (Stirrat et al, 1992), but new techniques (for example, endometrial resection and laparoscopic hysterectomy) are still being introduced with enthusiasm before proper evaluation of their role. Compared with obstetrics, gynaecology is, however, at a much earlier stage of development regarding either registries of randomized controlled trials or systematic reviews. Two review groups have already been established within the Cochrane Collaboration, the Subfertility Group and the Menstrual Disorders Group, with plans to create groups to evaluate the areas of fertility control, incontinence and gynaecological malignancy. Hence, in the specialty of obstetrics and gynaecology, we are particularly fortunate in the amount of information that has already been critically summarized for us.

544

I. E. C O O K E A N D D. L. S A C K E T T

The onus is therefore on us as obstetricians and gynaecologists for two reasons. First, a great deal of information has already been critically appraised and reviewed for us so we cannot simply say the evidence is rarely available. Instead, we must make sure that the evidence already collated for us is put into practice while continuing to review systematically the new information being produced. Second, obstetricians are dealing with a population different from that with which most doctors deal, a population in which the majority, at presentation and through their pregnancy, are well rather than ill. Third, but very importantly, there are two patients (both mother and the voiceless fetus) to consider in any outcome equation. OUR PRACTICE IS ALREADY BASED ON T I ~ EVIDENCE?

BEST

Is it already in practice? We only have to look at the vast variation of practice between countries, health authorities, hospitals and individual doctors within a single hospital to answer this question. Accepting that there is a need to centre care on the individual patient, it still seems unlikely that there could be so many right answers to exactly the same question if our present practice is truly evidence based. One wonders whether Archie Cochrane was too hasty in removing the wooden spoon from our specialty in 1989. Certainly, lain Chalmers and his reviewers have laid out a wealth of information for us in a very clear format. They made the registry of trials and have produced an enormous number of reviews that have not only reported those treatments which were either beneficial or harmful, but, equally importantly, also highlighted significant areas in which there is as yet no clear evidence one way or the other: 'We believe that if the type of information acquired by the National Perinatal Epidemiology Unit had been readily available ten to twenty years ago, and acted upon, some of the undesirable developments in the maternity services to which we have drawn attention would not have taken place': so says an inquiry in 1992 into maternity services in the UK. There are similar examples of the database being used for informing policy development by the World Health Organization and other government Health Policy and Research groups. In the UK, the Department of Health has provided complimentary copies of the Cochrane Library to all district health authorities. All we had to do was apply that information, but what have we really achieved with the data? Historically, many of our practices have either lingered beyond their clinical efficacy or languished despite their obvious effectiveness. Have we improved since the Pregnancy and Childbirth Database became available? It was 1972 when Liggins first reported the benefit to preterm babies of antenatal corticosteroids (Liggins and Howie, 1972). Figure 3 shows how the relative risk reduction of respiratory distress syndrome has changed little since 1972, but the increasing number of patients recruited to randomized controlled trials has increased the

EVIDENCE -BASED OBSTETRICS AND GYNAECOLOGY

545

precision of this effect, as shown by the narrowing of the 95% confidence intervals. The first systematic review of antenatal corticosteroids became available in 1990 (Crowley et al, 1990). It could be argued that this was the first time that the information was available to most obstetricians, yet within the UK it was another 4 years before the use of antenatal steroids was introduced into management guidelines in many delivery suites. In 1992 less than one quarter of the women whose babies would benefit from steroids had received them (Osiris Collaborative Group, 1992). The picture was no less encouraging in the USA in 1994, where only 12-18% of mothers who might have benefited actually received antenatal steroids (National Institutes of Health, 1994). If we are slow to implement new treatments once they have been appropriately assessed, have we been quicker to discard harmful or ineffective interventions? Routine electronic fetal heart rate monitoring in labour offers no demonstrable benefit in fetal outcome over intermittent auscultation for the low-risk pregnancy, but it does significantly increase the operative delivery rate (Neilsen, 1993, 1995). The information has been available for 6 years, but has this meant that we have implemented any change in practice? This is an interesting example for another reason, as it raises another 'old nut' with which obstetricians have lumbered themselves. Professor Murray Enkin says, 'By professing the ability to improve the health outcomes for already healthy women and their babies, obstetricians have a special responsibility to ensure that their practices are based on solid evidence that they do more good than harm'. Such an improvement was laid at the feet of electronic fetal monitoring in the 1970s before the randomized controlled trials were completed. Now we have a situation in which the paper record is deemed a permanent record that may be pivotal in later legal actions (Neilsen, 1993). There is continued discussion about the mode of delivery for breech presentations. The evidence from retrospective studies is contradictory (Cheng and Hannah, 1993; Danielian et al, 1996), and a randomized controlled trial of planned caesarean section versus planned vaginal delivery (with caesarean section if necessary) is hoped for (Hannah and Hannah, 1996). However, there is evidence of a significant decrease in both the number of non-cephalic presentations and caesarean sections when there is a policy of external cephalic version at term (Hofmeyer, 1995). What about the present? Magnesium sulphate was first suggested for the seizures of eclampsia in 1906 (Chesley, 1977) and has been popular for over 60 years in the USA (Sibai and Ramanathan, 1992), while in the UK only 2% of obstetricians had ever used it (Hutton et al, 1992). Now that the benefit of magnesium sulphate has so clearly been demonstrated, how many of us are sure that its administration has been implemented in our own hospitals? The most effective medical treatment for heavy menstrual bleeding is presently the antifibrinolytic tranexamic acid, but general practitioners prescribe it in only 5% of cases. In contrast, norethisterone (the least effective medical treatment) is prescribed most frequently (38% of cases) (Effective Health Care, 1995). What is your own prescribing policy?

546

I. E. C O O K E A N D D. L. S A C K E T T

DOES EVIDENCE-BASED MEDICINE KEEP US UP TO DATE? This need for easy access to clinically important information and to keep our clinical practice up to date has led to an increased interest in continuing medical education (CME). However, a systematic review of randomized controlled trials of traditional instructional CME has shown it to be ineffective in improving the health outcomes for our patients (Davis et al, 1992). When general practitioners were randomized to receiving CME packages with feedback tests on subjects that they ranked as high preference and subjects they ranked as low preference, or to the control group for whom CME was delayed for 18 months (Sibley et al, 1982), knowledge in the highpreference subjects improved in both the control and CME group but with no clinical significance. Where there was clinically significant improvement was in the topics of low preference, in which the CME group showed an improvement in quality of care compared with the control group. As Sackett (in press) says, 'CME only works when you don't want it'. Unfortunately, when assessed on subjects that were neither high or low preference, the performance of the general practitioners had continued to decline. The CME had not addressed the problem of our gradual decline in clinical competence. Is there really a decline in our competence? Unfortunately, there clearly is a problem. It has been repeatedly shown that there is a statistically and clinically significant negative correlation between our knowledge of up-todate care and the years that have elapsed since our graduation from medical school (Sackett et al, 1977; Evans et al, 1986; Ramsey et al, 1991). Can teaching and practising evidence-based medicine halt that decline? It has been shown to do just that in both the short and the long tenn. At McMaster University in Canada, medical students are taught through evidence-based medicine oriented tutorials. Students were randomized to receive either traditional clinical tutorials or evidence-based-style tutorials during one of their final clerkships. When assessed at the end of the clerkship, the group receiving traditional tutorials performed less well than they had at the beginning of their clerkship, while the other students had continued to improve in their diagnostic and management skills (Bennett et al, 1987). When McMaster students, graduating from this self-directed, problem-based, evidence-based curriculum, are compared with graduates from traditional didactic courses, they remained up to date with clinically important advances while the control group showed the expected decline in clinical competence. This difference was still present when last assessed, 15 years after graduation (Shin et al, 1993). SUMMARY 'At present, many clinical decisions are based principally on values and resources--opinion-based decision making; little attention has been given or is paid to evidence derived from research--the scientific factor' (Gray, in press). Our ultimate aim is to ensure the practice of effective medicine in

EVIDENCE-BASED OBSTETRICS AND GYNAECOLOGY

547

which, quite simply, the benefits to an individual patient or population outweigh any associated harm to that same patient or population. To do this, we need the skills to produce and evaluate the evidence on which our decisions are based. Evidence-based practice can help us to incorporate those skills into our working day. It depends on good clinical skills, forming a concise relevant question, becoming efficient in searching for the information, appraising that information, implementing the information into our daily practice and, finally, closing the circle by auditing our efforts at implementation and the effects within our own practice population. There seems no doubt that our patient care should be rooted in the best external evidence. Despite obstetricians, in particular, already having a great deal of information critically appraised and summarized for them, our clinical practice risks becoming out of date because of a propensity to lag behind the evidence as it stands, whether in discarding the ineffective or in introducing effective care policies. We need the techniques of evidence-based medicine to equip us as selfdirected learners in our quest to remain well-informed practitioners. We owe it to our patients to ensure that, in consultation with them, we are doing the right thing for them. REFERENCES Amman EM, Lau J; Kupelnick Bet al (1992) A comparison of results of meta-analyses of randomized controlled trials and recommendations of clinical experts. Treatments for myocardial infarction. Journal of the American Medical Association 268: 240-248. Beckmann CRB, Ling FW, Barzansky BM et al (1992) Fundamentals of Obstetrics and Gynaecology. Bennett KJ, Sacker DL, Haynes RB et al (1987) A controlled trial of teaching critical appraisal of clinical literature to medical students. Journal of the American Medical Association 257: 2451-2454. Cavell DG, Uman GC & Manning PR (1985) Information needs in office practice: are they being met? Annals of lnternal Medicine 103: 596-599. Chalmers I (ed.) (1992) Oxford Database of Perinatal Trials, Version 1.3. Oxford: Oxford University Press. Chalmers I, Enkin MW & Keirse MJNC (eds) (1989) Effective Care in Pregnancy and Childbirth. Oxford: Oxford University Press. Cheng M & Hannah ME (1993) Breech delivery at term--a critical review of the literature. Obstetrics and Gynecology 82: 605~518. Chesley LC (1977) Hypertensive Disorders of Pregnancy. New York: Appleton-Century-Crofts. Cochrane Library (1996) Cochrane Database of Systematic Reviews. Oxford: Update Software. Available from British Medical Journal Publishing Group, London. Cragin E (1916) Conservatism in obstetrics. New York State Journal of Medicine 104: 1-3. Crichton M (1971) In my clinical experience. New England Journal of Medicine 285:1491 (letter). Crowley PA (1995) Antenatal corticosteroid therapy: a meta-analysis of the randomized trials, 1972 to 1994. American Journal of Obstetrics and Gynecology 173: 322-335. Crowley PA, Chalmers I & Kierse MJNC (1990) The effects of administration before preterm delivery: an overview of the evidence from controlled trials. British Journal of Obstetrics and Gynaecology 97: 11-25. Danielian PJ, Wang J & Hall MH (1996) Long-term outcome of term breech presentation by method of delivery. British Medical Journal 312: 1451-1453. Davidoff F, Haynes RB, Saekett DL et al (1995) Evidenced-based Medicine: a new journal to help doctors identify the information they need. British Medical Journal 310" 1085-1086. Davis DA, Thompson MA, Oxman AD et al (1992) Evidence for the effectiveness of CME: a review of 50 randomized controlled trials, Journal of the American MedicaIAssociation 268:1111-1 l 17,

548

I. E. COOKE AND D. L. SACKETT

Department of Health (1993) Changing Childbirth. A Report of the Expert Maternity Group. London: HMSO. Echt DS, Liebson PR, Mitchell B et al (1991) Mortality and morbidity in patients receiving encainide, flecainide or placebo: the Cardiac Arrhythmia Suppression Trial. New England Journal of Medicine 324: 781-788. Eclampsia Trial Collaborative Group (1995) Which anticonvulsant for women with eclampsia? Evidence from the Collaborative Eclampsia Trial. Lancet 345: 1455-1463. Effective Health Care (1995) The management of menorrhagia. Bulletin no. 6. York: NHS Centre for Reviews and Dissemination. Ellis J, Mulligan I, Rowe J & Sackett DL (1995) Inpatient general medicine is evidence based. Lancet 346: 407-410. Enkin MW (in press) The need for evidence-based obstetrics. Evidence-based Medicine. Enkin MW, Keirse MJNC, Renfrew MJ & Neilsen JP (1995a) Guide to Effective Care in Pregnancy and Childbirth, 2nd edn. Oxford: Oxford University Press. Enkin MW, Keirse MJNC, Renfrew MJ & Neilsen JP (1995b) Pregnancy and Childbirth Database. Oxford: Update Software. Available from British Medical Journal Publishing Group, London. Evans CE, Haynes RB, Birkett NJ et al (1986) Does a mailed continuing education program improve clinician performance? Results of a randomized trial in antihypertensive care. Journal of the American Medical Association 255: 501-504. Geddes JR, Game D, Jenkins NE et al (1996) In-patient psychiatric care is evidence-based. Proceedings of the Royal College of Psychiatrists Winter Meeting, Stratford, UK, 23-25 January. Gill P, Dowell AC, Neat RD et al (1996) Evidence-based general practice: a retrospective study of interventions in one training practice. British Medical Journal 312: 819-821. Gray M (in press) Evidence-based Health Care. London: Chtavhill Livingstone. Grimes DA (1995) Introducing evidence-based medicine into a department of obstetrics and gynecology. Obstetrics and Gynecology 86:451-457 Hannah ME & Hannah W (1996) Caesarean section or vaginal birth for breech presentation at term. British Medical Journal 312:1433-1434 Haynes RB (in press) Searching for the evidence. Evidence-based Medicine. Hofmeyr GJ (1995) ECV at term [revised 4 October 1993]. In Keirse MJNC, Renfrew MJ, Neilsen JP & Crowther C (eds) Pregnancy and Childbirth Module. Cochrane Database of Systematic Reviews. Cochrane Collaboration, Issue 2. Oxford: Update Software. Available from British Medical Journal Publishing Group, London. Hughes E, Fedorkow D, Colin J & Vandekerckhove P (1996) Ovulation suppression vs placebo in the treatment of endometriosis. In Lilford R, Hughes E & Vandekerckhove P (eds) Subfertility Module of The Cochrane Database of Systemic Reviews (updated 6 September 1996). Available in The Cochrane Library (database on disk and CD ROM). The Cochrane Collaboration; Issue 3, Oxford: Update Software; 1996. Updated quarterly. Available from: BMJ Publishing Group, London. Hutton JD, James DK, Stirrat GM et al (1992) Management of severe pre-eclampsia and eclampsia by UK consultants. British Journal of Obstetrics and Gynaecology 99: 554-556. Johnston RA & Sidall RS (1992) Is the usual method for preparing patients for delivery beneficial or necessary? American Journal of Obstetrics and Gynecology 4: 645-650. Liggins GC & Howie RN (1972) A controlled trial of antepartum glucocorticoid treatment for prevention of the respiratory distress syndrome in premature infants. Paediatrics 50:515-525. National Institutes of Health (1994) Effect of corticosteroids for fetal maturation on perinatal outcomes. NIH Consensus Statement 12(2): 1-23. Neilsen JP (1993) Cardiotocography during labour. British Medical Journal 306: 347-348. Neilsen JP (1995) EFM + scalp sampling vs intermittent auscultation in labour. [revised 4 May 1994] In Keirse MJNC, Renfrew MJ, Neilsen JP & Crowther C (eds) Pregnancy and Childbirth Module. The Cochrane Database of Systematic Reviews. Cochrane Collaboration, Issue 2. Oxford: Update Software. Available from British Medical Journal Publishing Group, London. Osiris Collaborative Group (1992) Early versus delayed neonatal administration of synthetic surfactant. Lancet 340: 1363-t369. Ramsey PG, Carline D, lnui TS et al (1991) Changes over time in the knowledge base of practising internists. Journal of the American Medical Association 266:1103-1107. Richardson WS (in press) How to ask clinical questions that you can answer. In Sackett DL, Richardson WS, Rosenberg WMC & Haynes RB (eds) Evidence-based Medicine: How to Practise and Teach EBM. London: Churchill-Livingstone (in press).

EVIDENCE-BASED OBSTETRICS AND GYNAECOLOGY

549

Sackett DL (in press) On the need for evidence-based medicine. In Sacker DL, Richardson WS, Rosenberg WMC & Haynes RB (eds) Evidence-based Medicine: How to Practise and Teach EBM. London: Churchill-Livingstone (in press). Sackett DL, Haynes RB, Taylor DW et al (t977) Clinical determinants of the decision to treat primary hypertension. Clinical Research 24: 648. Sackett DL, Rosenberg WMC, Gray JAM et a! (1996) Evidenced-based medicine: what it is and what it isn't. British Medical Journal 312: 71-72. Sackett DL, Richardson WS, Rosenberg WMC & Haynes RB (in press) Evidence-based Medicine: How to Practise and Teach EBM. London: Churchill-Livingstone, in press. Shin JH, Haynes BR & Johnston ME (1993) Effect of problem-based, self-directed undergraduate education on life-long learning. Canadian Medical Association Journal 148: 969-976. Sibai BM & Ramanathan J (1992) The case for magnesium in preeclampsia-eclampsia. International Journal of Obstetric Anesthesia 1: 167-175. Sibley JC, Sackett DL, Neufeld Vet al (1982) A randomized trial of continuing medical education. New England Journal of Medicine 306:511-515. Sinclair JC (1995) Meta-analysis of randomized controlled trials of antenatal corticosteroid for prevention of respiratory distress syndrome: discussion. American Journal o f Obstetrics and Gynecology 173: 335-344. Stirrat GM, Farndon J, Ferrow SC & Dwyer N (1992) The challenge of evaluating surgical procedures. Annals of the Royal College of Surgeons 74: 80-84. Tumbull A & Chamberlain G (eds) (1989) Obstetrics, 1st edn. Edinburgh: Churchill Livingstone.