By H. Mufassa. School of the Visual Arts.
A disabled prem ature infant in need of an intensive care cot will purchase viagra 25 mg online erectile dysfunction statistics singapore, argues H arris purchase viagra 50 mg mastercard erectile dysfunction protocol + 60 days, be allocated m ore resources than it deserves in com parison with a 50 year old wom an with cancer, since the infant, were it to survive, would have so m any m ore life years to quality adjust. Som e of the ones that were in vogue when this book went to press include the following. In m y view, they all have potential uses but none of them is an absolute or incontrovertible m easure of health or illness! This approach, known as cost consequences analysis, presents the results of the econom ic analysis in a disaggregated form. In other words, it expresses different outcom es in term s of their different natural units (i. Cost consequences analysis allows for the health state preference values of both individuals and society to change with tim e and is particularly useful when these are disputed or likely to change. This approach m ay also allow the analysis to be used by different groups or societies from the ones on which the original trial was perform ed. I strongly recom m end that for a m ore definitive list, you check out these sources, especially the official recom m endations by the BM J working group. Before you attem pt to digest what a paper says about costs, quality of life scales or utilities, m ake sure that the trial being analysed is scientifically relevant and capable of giving unbiased and unam biguous answers to the clinical question posed in its introduction (see Chapter 4). Furtherm ore, if there is clearly little to choose between the interventions in term s of either costs or benefits, a detailed econom ic analysis is probably pointless. From the patient’s point of view, he or she generally wants to get better as quickly as possible. From the Treasury’s point of view, the m ost cost effective health intervention is one that returns all citizens prom ptly to taxpayer status and, when this status is no longer tenable, causes im m ediate sudden death. From the drug com pany’s point of view, it would be difficult to im agine a cost–benefit equation which did not contain one of the com pany’s products and from a physiotherapist’s point of view, the rem oval of a physiotherapy service would never be cost effective. M ost assum e the perspective of the health care system itself, although som e take into account the hidden costs to the patient and society (for exam ple, due to work days lost). There is no "right" perspective for an econom ic evaluation but the paper should say clearly whose costs and whose benefits have been counted "in" and "out". Question 3 Have the interventions being compared been shown to be clinically effective? The paper you are reading m ay sim ply be an econom ic analysis, in which case it will be based on a previously published clinical trial, or it will be an econom ic evaluation of a new trial whose clinical results are presented in the sam e paper. Either way, you m ust m ake sure that the intervention that "works out cheaper" is not substantially less effective in clinical term s than the one that stands to be rejected on the grounds of cost. A research trial that com pares one obscure and unaffordable intervention with another will have little im pact on m edical practice. Rem em ber that standard current practice (which m ay be "doing nothing") should alm ost certainly be one of the alternatives com pared. Too m any research trials look at intervention packages which would be im possible to im plem ent in the non-research setting (they assum e, for exam ple, that general practitioners will own a state of the art com puter and agree to follow a protocol, that infinite nurse tim e is available for the taking of blood tests or that patients will m ake their personal treatm ent choices solely on the basis of the trial’s conclusions). N ow im agine a m ore com plicated exam ple – the rehabilitation of stroke patients into 160 PAPERS TH AT TELL YOU W H AT TH IN G S COST their own hom es with attendance at a day centre com pared with a standard alternative intervention (rehabilitation in a long stay hospital). The econom ic analysis m ust take into account not just the tim e of the various professionals involved, the tim e of the secretaries and adm inistrators who help run the service, and the cost of the food and drugs consum ed by the stroke patients, but also a fraction of the capital cost of building the day centre and m aintaining a transport service to and from it. If calculating "cost per case" from first principles, rem em ber that som eone has to pay for heating, lighting, personnel support, and even the accountants’ bills of the institution. In general term s, these "hidden costs" are known as overheads and generally add an extra 30–60% onto the cost of a project. The task of costing things like operations and outpatient visits in the U K is easier than it used to be because these experiences are now bought and sold within the N H S at a price which reflects (or should reflect) all overheads involved. Be warned, however, that unit costs of health interventions calculated in one country often bear no relation to those of the sam e intervention elsewhere, even when these costs are expressed as a proportion of G N P. Benefits such as earlier return to work for a particular individual can, on the face of it, be m easured in term s of the cost of em ploying that person at his or her usual daily rate. This approach has the unfortunate and politically unacceptable consequence of valuing the health of professional people higher than that of m anual workers, hom em akers or the unem ployed and that of the white m ajority higher than that of (generally) lower paid m inority ethnic groups. It m ight therefore be preferable to derive the cost of sick days from the average national wage. In a cost effectiveness analysis, changes in health status will be expressed in natural units (see section 10. But just because the units are natural does not autom atically m ake them appropriate.
In reality buy viagra 100mg cheap erectile dysfunction cream, there is a great deal of overlap between them purchase viagra 50mg free shipping zantac causes erectile dysfunction, the im portance of which is increasingly being recognised. D oes not use preset questions but is shaped by a defined set of topics Focus groups M ethod of group interview that explicitly includes and uses the group interaction to generate data Box 11. It begins with an 168 PAPERS TH AT G O BEYON D N U M BERS intention to explore a particular area, collects "data" (i. The strength of qualitative research lies in validity (closeness to the truth), i. The validity of qualitative m ethods is greatly im proved by the use of m ore than one m ethod (see Box 11. Those who are ignorant about qualitative research often believe that it constitutes little m ore than hanging out and watching leaves fall. It is beyond the scope of this book to take you through the substantial literature on how to (and how not to) proceed when observing, interviewing, leading a focus group, and so on. But sophisticated m ethods for all these techniques certainly exist and if you are interested I suggest you try the introductory7, 10, 11 or m ore detailed2, 12 texts listed at the end of this chapter. Qualitative m ethods really com e into their own when researching uncharted territory, i. But it is in precisely these circum stances that the qualitative researcher m ust ensure that (s)he has, at the outset, carefully delineated a particular focus of research and identified som e specific questions to try to answer (see Question 1 in section 11. The m ethods of qualitative research allow for and even encourage2 m odification of the research question in the light of findings generated along the way. Failure to recognise the legitim acy of this approach has, in the past, led critics to accuse qualitative researchers of continually m oving their own goalposts. W hilst these 169 H OW TO READ A PAPER criticism s are often m isguided, there is, as N icky Britten and colleagues have observed, a real danger "that the flexibility [of the iterative approach] will slide into sloppiness as the researcher ceases to be clear about what it is (s)he is investigating". It is debatable, therefore, whether an all-encom passing critical appraisal checklist along the lines of the "U sers’ guides to the m edical literature" (see references 8–32 in Chapter 3) could ever be developed. M y own view, and that of a num ber of individuals who have attem pted or are currently working on this very task,7, 12, 13, 14 is that such a checklist m ay not be as exhaustive or as universally applicable as the various guides for appraising quantitative research, but that it is certainly possible to set som e ground rules. The list which follows has been distilled from the published work cited earlier2, 7, 13 and also from discussions with D r Rod Taylor of Exeter U niversity, who has worked with the CASP Project on a m ore detailed and extensive critical appraisal guide for qualitative papers. Question 1 Did the paper describe an important clinical problem addressed via a clearly formulated question? Qualitative papers are no exception to this rule: there is absolutely no scientific value in interviewing or observing people just for the sake of it. Papers which cannot define their topic of research m ore closely than "W e decided to interview 20 patients with epilepsy" inspire little confidence that the researchers really knew what they were studying or why. You m ight be m ore inclined to read on if the paper stated in its 170 PAPERS TH AT G O BEYON D N U M BERS introduction som ething like, "Epilepsy is a com m on and potentially disabling condition, and up to 20% of patients do not rem ain fit free on m edication. Antiepileptic m edication is known to have unpleasant side effects, and several studies have shown that a high proportion of patients do not take their tablets regularly. W e therefore decided to explore patients’ beliefs about epilepsy and their perceived reasons for not taking their m edication". If the objective of the research was to explore, interpret or obtain a deeper understanding of a particular clinical issue, qualitative m ethods were alm ost certainly the m ost appropriate ones to use. If, however, the research aim ed to achieve som e other goal (such as determ ining the incidence of a disease or the frequency of an adverse drug reaction, testing a cause and effect hypothesis or showing that one drug has a better risk–benefit ratio than another), qualitative m ethods are clearly inappropriate! If you think a case- control, cohort study or random ised trial would have been better suited to the research question posed in the paper than the qualitative m ethods that were actually used, you m ight like to com pare that question with the exam ples in section 3. A random sam ple will ensure that the results reflect, on average, the condition of the population from which that sam ple was drawn. In qualitative research, however, we are not interested in an "on average" view of a patient population. W e want to gain an in-depth understanding of the experience of particular individuals or groups 171 H OW TO READ A PAPER and we should therefore deliberately seek out individuals or groups who fit the bill. If, for exam ple, we wished to study the experience of non-English speaking British Punjabi wom en when they gave birth in hospital (with a view to tailoring the interpreter/advocacy service m ore closely to the needs of this patient group), we would be perfectly justified in going out of our way to find wom en who had had a range of different birth experiences – an induced delivery, an em ergency caesarean section, a delivery by a m edical student, a late m iscarriage, and so on. W e would also wish to select som e wom en who had had shared antenatal care between an obstetrician and their general practitioner and som e wom en who had been cared for by com m unity m idwives throughout the pregnancy. In this exam ple, it m ight be particularly instructive to find wom en who had had their care provided by m ale doctors, even though this would be a relatively unusual situation. Finally, we m ight choose to study patients who gave birth in the setting of a large, m odern, "high- tech" m aternity unit as well as som e who did so in a sm all com m unity hospital.
Achalasia: outcome of patients treated with intrasphincteric injection 27 Tsui JKC viagra 25 mg free shipping erectile dysfunction nerve,Bhatt M buy viagra 25mg erectile dysfunction and diabetes ppt,Calne S,Calne DB. The occasion was the examina- affect the outcome favourably by enabling treatment to Practice,University of Queensland,The tion in general practice for fifth year medical students. With other causes such as minimal change University General We run an objective structured clinical examination. Australia blood pressure (the "patient" was actually someone I consulted my general practice colleague. His Chris Del Mar recruited from our general practice), test his urine approach was similar. He ensured that I had checked professor using a dipstick, and report to the examiner within the my urine microscopy and culture to establish whether c. He wondered whether my bicycle rid- ing might be the cause, and suggested I recheck the BMJ 2000;320:165–6 testing. Because I did not want to disturb the volunteer patient, I collected it from myself. If test results were still posi- patient’s blood pressure again (this had to be done tive, it looked as if the cascade of likely events would after every 10th student)—it was stable. And I tested the include ultrasonography, urine samples for malignant urine to check it was normal—it was not. I had time to think about not a problem as far as the examination was concerned adopting an evidence based approach. I tested Formulating the question my urine again a week later, and when I found it was still positive I sent a specimen to the laboratory. The report The most difficult part of adopting evidence in practice stated that urine culture was negative but confirmed the is formulating the question. The model that is the chance of having a serious condition with sprang to mind first is summarised in the table. Ideally, it would be huge study of general tuberculosis and schistosomiasis as causes of haema- turia. A textbook of medicine2 suggested further Causes and management of haematuria assessments, including checking my blood relatives for Site of bleeding Disease Management urine abnormality and carrying out haemoglobin elec- Generalised Bleeding diathesis Check bleeding and coagulation profiles; trophoresis and 24 hour urinary estimations of urate treat accordingly and calcium excretion. If all these investigations were Lower renal tract Prostate hypertrophy or cancer; Cystoscopy; treat accordingly negative, intravenous urography, cystoscopy, and renal urethral inflammation; bladder lesion computed tomography were proposed, with indefinite or cancer Ureteric lesions Transitional cell carcinoma; ureteric Ultrasonography or intravenous regular follow up thereafter. The essential feature of calculi urography; treat accordingly this model is that identifying the lesion anatomically or Renal lesions Cancer; calculi; vascular abnormalities; Check blood pressure; ultrasonography physiologically is the key to managing the problem. Neither exercise, recent sexual inter- course, nor flying were associated with microscopic Searching for evidence haematuria, although recall of a history of urethritis The standard textbooks on my shelf were no help in was. This would have been the most The clinical decision convenient source of data and is strong on evidence for different treatments, but unfortunately it does not yet What should I do now? I decided that the chance of include routinely collected data on the course of having an adverse outcome was not sufficiently high diseases and conditions. My search strat- adopt a management policy of "expectant observa- egy was simple,3 and probably sensitive at the expense tion. Inspection of titles helped me discard immediately I have applied my own values to the clinical about half the 230 hits, but reading through the printout decision. If, in similar circumstances, a patient of mine of abstracts of the remainder took an evening. There elected to proceed with further investigations, I would were no systematic reviews—the best form of evidence. This does not address matters of gatekeeping Two articles were clearly useful because they described (resource allocation), which probably should be dealt large studies with long term follow up of people with with away from the consultation. The The evidence main difference was the change in clinical thinking that In a British study, 2. Some a serious condition that was amenable to cure—two answers are difficult to find. We a prognosis of the outcome someone like me (my situ- also need a forum of peers and those skilled at ation being similar to screening) would expect. It evidence based medicine in which test out our ideas so suggested that I was unlikely to have a serious that we can reassure ourselves that we are not condition that was amenable to cure. If health authorities are serious this may be an overestimate of the benefits of about promoting evidence based medicine in clinical screening. Perhaps those three people would have practice, they may have to consider providing a service developed symptoms such as frank haematuria or (perhaps like pathology, radiology, or referred special- dysuria sufficiently early to negate the beneficial effect ist opinions) to help clinicians to take these steps.
Papers have occasionally been written (and purchase 75 mg viagra otc erectile dysfunction gel treatment, in the past order viagra 25 mg without prescription erectile dysfunction melanoma, published) in which nothing has been done except perform the new test on a few dozen subjects. This exercise m ay give a range of possible results for the test, but it certainly does not confirm that the "high" results indicate that the target disorder (the disease you are looking for) is present or that the "low" results indicate that it isn’t. N ext, you should verify that the "gold standard" test used in the survey m erits the term. For m any conditions, there is no absolute gold standard diagnostic test which will say for certain if it is present or not. U nsurprisingly, these tend to be the very conditions for which new tests are m ost actively sought! H ence, the authors of such papers m ay need to develop and justify a com bination of criteria against which the new test is to be assessed. One specific point to check is that the test being validated here (or a variant of it) is not being used to contribute to the definition of the gold standard. If you validated a new test for cholesterol in 100 healthy m ale m edical students, you would not be able to say how the test would perform in wom en, children, older people, those with diseases that seriously raise the cholesterol level or even those who had never been to m edical school! Although few people would be naïve enough to select quite such a biased sam ple for their validation study, one paper found that only 27% of published studies explicitly defined the spectrum of subjects tested in term s of age, sex, sym ptom s and/or disease severity, and specific eligibility criteria. A particular diagnostic test m ay, conceivably, be m ore sensitive in fem ale subjects than m ales or in younger rather than older subjects. For the sam e reasons, as Sackett and colleagues stipulate, the subjects on which any test is verified should include those with both m ild and severe disease, treated and untreated, and those with different but com m only confused conditions. This is why general practitioners are, often rightly, sceptical of the utility of tests developed exclusively in a secondary care population, where the severity of disease tends to be greater (see section 4. It sim ply m eans, "did everyone who got the new diagnostic test also get the gold standard, and vice versa? I hope you have no problem spotting the potential bias in studies where the gold standard test is only perform ed on people who have already tested positive for the test being validated. There are, in addition, a num ber of m ore subtle aspects of work up bias which are beyond the scope of this book. If you are interested, you could follow the discussion on this subject in Read and colleagues’ paper. Expectation bias occurs when pathologists and others who interpret diagnostic specim ens are subconsciously influenced by the knowledge of the particular features of the case; for exam ple, the presence of chest pain when interpreting an ECG. In the context of validating diagnostic tests against a gold standard, the question m eans "D id the people who interpreted one of the tests know what result the other test had shown on each particular subject? Question 6 Was the test shown to be reproducible both within and between observers? If the sam e observer perform s the sam e test on two occasions on a subject whose characteristics have not changed, they will get different results in a proportion of cases. All tests show this feature 113 H OW TO READ A PAPER to som e extent, but a test with a reproducibility of 99% is clearly in a different league from one with a reproducibility of 50%. A num ber of factors m ay contribute to the poor reproducibility of a diagnostic test: the technical precision of the equipm ent, observer variability (for exam ple, in com paring a colour with a reference chart), arithm etical errors, and so on. G iven the sam e result to interpret, two people will agree in only a proportion of cases, generally expressed as the score. If the test in question gives results in term s of num bers (such as the blood cholesterol level in m m ol/l), interobserver agreem ent is hardly an issue. If, however, the test involves reading X-rays (such as the m am m ogram exam ple in section 4. Question 7 What are the features of the test as derived from this validation study? All the above standards could have been m et, but the test m ight still be worthless because the test itself is not valid, i. That is arguably the case for using urine glucose as a screening test for diabetes (see section 7. After all, if a test has a false negative rate of nearly 80% , it is m ore likely to m islead the clinician than assist the diagnosis if the target disorder is actually present. There are no absolutes for the validity of a screening test, since what counts as acceptable depends on the condition being screened for.
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