Bailliere's clinical obstetrics and gynaecology最新文献

Diagnosis-based decision-making is fundamental to clinical practice. In this chapter, we have seen how clinical symptoms can select a group of patients in whom diagnostic tests can then help the clinician to reach or exclude a diagnosis. Informed use of a diagnostic test requires identification of valid evaluations of its diagnostic abilities. Conventional measures of a test's effectiveness, such as sensitivity and specificity, are of limited use when applying diagnostic tests in clinical practice. Likelihood ratios provide an explicit tool for updating diagnostic probabilities according to test results, and can incorporate variations between individuals in their risk of disease. Their use may help both individual patient management and the appropriate allocation of diagnostic and therapeutic resources.

Numerous obstacles stand in the way of evidence-based medicine in obstetrics and gynaecology. These include seduction by clinical authorities, the false idol of technology, the tendency to let sleeping dogmas lie, the pursuit of pedantry in medical education, and the problem of clinical numerators in search of a denominator. Recognizing the importance of placing our practice on a more scientific footing, we launched evidence-based medicine in our department in a municipal academic hospital in 1993. We orient all new clinicians to the process of evidence-based medicine and level the intellectual playing field. As clinical questions arise, we decide them in a group setting using the best available evidence. This has led to a number of changes in practice. Easy access to information around the clock is fundamentally important. Resources include access to literature searches, the Internet, the Cochrane Collaboration on Pregnancy and Childbirth, ACOGNET and Epi Info 6. Evidence-based medicine equips clinicians to practise safely and effectively both now and, what is more important, in the next century.

Obstetricians and gynaecologists often have to assess whether an exposure is causing a harmful effect. The first part of this assessment involves considering how the results were obtained: can the type of study determine a cause-and-effect relationship; were all subjects at similar risk of being exposed to the putative harmful exposure and of developing the outcome of interest; was information about the exposure ascertained in the same way from all subjects; could knowledge of an individual's exposure status have influenced how the outcome was ascertained? Next, the results themselves need to be considered: what was the size and precision of the risk estimate; could there be other explanations, such as bias and confounding, for the results; were there other pointers, like a dose gradient, consistency with other studies or biological plausibility, which suggest a causal relationship? Finally, the clinical implications of the results need to be evaluated: are the findings applicable to today's clinical practice; who do they apply to; what are the numbers needed to harm? By addressing each of these points, clinicians can determine whether an apparently harmful effect is important and so decide whether they need to change their medical practice.

In the current era of patients seeking better information, managers seeking cost-effective treatments, clinicians struggling to keep up with the expanding medical literature, and professional groups requiring continuing medical education, there is a clear need for up-to-date and relevant systematic reviews of the effectiveness of treatment within our specialty. Such reviews will play an increasing role in the education of health professionals and lay people, in the evolution of the health service and in the direction of future research. The Cochrane Collaboration provides the infrastructure for the development and dissemination of these reviews. The specialty of obstetrics and gynaecology will benefit from several related groups already working within the Cochrane Collaboration (Pregnancy and Childbirth, Subfertility, Menstrual Disorders and Incontinence). Other groups are in the process of, or likely to, register in the near future (Fertility Control, Gynaecological Cancer). However, the need and demand for a large number of systematic reviews exceeds the current capacity of those who have committed themselves to prepare and maintain such reviews, and substantial challenges remain. However, there is every reason to believe that a concerted effort over many years will be worth while. Earlier in this commentary, obstetrics and gynaecology was referred to as the specialty most deserving of the ‘wooden spoon’ for its lack of evidence-based practice. With the development of various gynaecological groups within the Collaboration, we hope that the ‘wooden spoon’ can be discarded from our ranks for good.

When the Cochrane Collaboration fulfils its quest to organize the available evidence in a registry of trials and systematic reviews, it will mean that our task to find the best evidence will be much less daunting than it may at present seem. Meanwhile, to be evidence-based practitioners, we must learn the techniques that will make our search both comprehensive and efficient. To find this evidence requires:o

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   the construction of a specific question based on the clinical problem;

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   the design of a search strategy that is inclusive but practical;

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   the search of the appropriate database(s);

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   the scan of the retrieved abstracts for the most useful papers for critical appraisal.

Efficient searching for evidence does mean getting to grips with the manifold advantages that computerization can offer us. The use of a computer for this purpose needs, like any other new technique we take on, practice to gain competence and confidence. Within the UK, the National Health Service Research and Development Department has made the collation and dissemination of clinical evidence to practitioners a priority. Hence at present, there is an enormous effort within the UK to make sure that the evidence is in the clinical areas of need, in a format we can use it and available in a place where and when we want it, whether that is the ward or the general practitioner's surgery. The aim is to remove at least some of the barriers that prevent us from becoming individual evidence-based practitioners.

‘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 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 self-directed 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.

The menopausal transition is that period beginning with the first indications of the approach of menopause and ending with the final menses. Its morphological basis is a rapidly declining number of primordial follicles within the ovary; a decline which appears to result from an increased rate of follicular atresia. The most characteristic hormonal change in the menopausal transition is a progressive, though often fluctuating, rise in the level of serum FSH. Oestradiol and inhibin levels fluctuate markedly when observed in individual subjects but remain relatively preserved during the follicular phase of the cycle, until late in the menopausal transition. The frequency of anovulatory cycles increases as the final menstrual period approaches. The rate of symptom reporting varies among different populations of women, with maximum symptom frequency being seen during the menopausal transition. There are some indications that cardiovascular and osteoporosis risk factors may change adversely during the menopausal transition and medical practitioners should be ready to offer hormonal supplementation to women at increased risk of cardiovascular disease and osteoporotic fracture.

The endometrial effects of HRT are of prime importance in compliance with long-term use, and safety with therapy. Different regimens have to be advocated according to menopausal status, to produce acceptable bleeding patterns.

Despite the clinical impressions that there are considerable psychological benefits from HRT, there is only clear evidence for amelioration of psychological symptoms (including improvement in cognitive function) in women who have undergone a surgical menopause. Otherwise in the natural menopause it remains unclear which, if any, non-sexual psychological symptoms respond directly to oestrogen except as a secondary response to reduction in physical symptoms. Overall, it has to be said that there is little scientific backing for hormonal treatment of psychological problems on their own around the time of the natural menopause. In most cases psychological treatment or counselling will be more appropriate than HRT.

It must be remembered that the prevalence of psychological symptoms in the menopause and gynaecology clinic is high just as it is in all hospital settings. The task is to identify which women:o

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   Have a predominance of psychological symptoms and might have psychiatric disorders. They may have presented in the clinic because they also happen to be menopausal, but it may well be that the psychiatric disorder has a quite independent aetiology. They will benefit from specific treatment for that disorder.

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   Have, and complain of, low moods or other non-specific psychological symptoms and have presented in the clinic because they are menopausal. They might benefit from practical, supportive help with current and ongoing stresses and strains.

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   Present appropriate menopausal complaints and only on enquiry reveal their psychological problems. In particular, disorders such as depressive illness, anxiety states and alcohol abuse can present with physical symptoms including ones which mimic vasomotor ones. This group may well be non-responders to HRT.

Women requiring particular consideration might be those with other health problems (particularly chronic ones that might carry on in to old age) who are possibly more at risk of developing depression as they pass through the menopause.

There is clearer evidence that HRT has beneficial effects on sexual function. When sexual symptoms are presented it is worth clarifying the exact features contributing to the complaint. Is it a problem of sexual interest, of infrequency of sexual activity, of vaginal dryness and dyspareunia, or is it a mixture of these complaints?

Reduction of sexual interest and reduced sexual activity with the partner and possibly orgasm may accompany the menopause. Oestrogens have been shown to have some beneficial effect on sexual desire. Where oestrogen alone is ineffective, testosterone is usually beneficial. This treatment effect is particularly clear in surgically menopausal women.

Non-menopausal aspects of the sexual relationship must be considered too. These aspects include the quality of the relatio