[Validity of Recommendations for Secondary Prevention of Colon Cancer]

BACKGROUND

Prevention programmes should only be recommended if they achieve what they promise to achieve. Therefore, we checked the variation and validity of recommendations for screening for colorectal cancer of nine organisations.

METHODS

We analysed the information concerning recommended screening age, guaiac faecal occult blood test (gFOBT), faecal immunological test (FIT), faecal DNA test, sigmoidoscopy, colonoscopy, double-contrast examination/double-contrast barium enema, and virtual colonoscopy/CT colonography in the following three steps: 1) we gathered the references quoted by the nine organisations; 2) references were categorised according to mortality, incidence and sensitivity/specificity; 3) the validity of references that reported reduced mortality attributed to screening were evaluated.

RESULTS

Evidence of occult faecal blood was the only screening method recommended by all nine organisations. Colonoscopy was recommended by seven organisations. Fifteen of the 33 references used endpoints other than mortality to justify screening. One publication was a meta-analysis. Eleven of 17 publications evaluated the gFOBT, three evaluated sigmoidoscopy, one FIT, one coloscopy, and one general diagnosis of the intestine. On average, two of nine validity criteria were completely fulfilled, five only partially, and two were not fulfilled. In two publications, none of the validity criteria were completely met.

CONCLUSION

Analysis of screening for colorectal cancer revealed that nine organisations had different goals and different recommendations. Scrupulous and thorough evaluation of the scientific studies in relation to mortality, upon which these recommendations are based, revealed numerous shortcomings and therefore could not sufficiently substantiate the international recommendations for screening for colorectal cancer. It would be useful to establish a consensus about which data have to be collected to provide a reliable basis for health-care decisions.

[Clinical economics: a concept to optimize healthcare services]

Clinical economics strives to support healthcare decisions by economic considerations. Making economic decisions does not mean saving costs but rather comparing the gained added value with the burden which has to be accepted. The necessary rules are offered in various disciplines, such as economy, epidemiology and ethics. Medical doctors have recognized these rules but are not applying them in daily clinical practice. This lacking orientation leads to preventable errors. Examples of these errors are shown for diagnosis, screening, prognosis and therapy. As these errors can be prevented by application of clinical economic principles the possible consequences for optimization of healthcare are discussed.

[Clinical ecomomics: a pleading for complementing the medical curriculum and specialty training]

Clinical economics requires an understanding of clinical relationships just like health economy requires an understanding of economic relationships. Hitherto we have ensured that economists can differentiate symptoms from diagnoses and diagnostics from screening at the interface between medicine and economy. However, we overlooked the fact that physicians should be able to understand the principles of marginal benefit and medical ethics, as well as the differences among efficacy, effectiveness, and benefit, to be able to make sound decisions. To make up for this neglected demand, we present our definition of clinical economics, identify the potential conflicts between medical professionalism and commercialized medicine, describe the importance - but also the limits - of scientific evidence, explain the difference between 'prioritization' and strict rationing, and attempt to justify the fact that the necessary changes in the provision of healthcare will probably only be achieved if we instill this new way of thinking in medical students during their medical education. Complementing the medical curriculum with clinical economics would achieve this goal.

[Methods of health economic evaluation for health services research]

On August 30, 2010, the German Network for Health Services Research [Deutsches Netzwerk Versorgungsforschung e. V. (DNVF e. V.)] approved the Memorandum III "Methods for Health Services Research", supported by the member societies mentioned as authors and published in this Journal [Gesundheitswesen 2010; 72: 739-748]. The present paper focuses on methodological issues of economic evaluation of health care technologies. It complements the Memorandum III "Methods for Health Services Research", part 2. First, general methodological principles of the economic evaluations of health care technologies are outlined. In order to adequately reflect costs and outcomes of health care interventions in the routine health care, data from different sources are required (e. g., comparative efficacy or effectiveness studies, registers, administrative data, etc.). Therefore, various data sources, which might be used for economic evaluations, are presented, and their strengths and limitations are stated. Finally, the need for methodological advancement with regard to data collection and analysis and issues pertaining to communication and dissemination of results of health economic evaluations are discussed.

[Validity of clinical trials: are there differences between conventional and complementary alternative medicine?]

So far there has been no consensus on the criteria which confirm the validity of scientific contributions in conventional medicine (CM) and complementary/ alternative medicine (CAM). An interdisciplinary group of experts from various disciplines within each of the areas of medicine held six well-documented sessions in an effort to reach a consensus. The group agreed that the methods to confirm the validity of clinical trials are identical in CM and CAM. There are differences in research strategies and there may also be differences in interpreting the results, depending on the concept of medicine.

[Significance of outcomes research for health insurance]

Innovation is an important stimulus of the economy and the healthcare system. Two components may inhibit innovations, an increased risk of the developers to market their innovations and an increased risk of the public to increase the costs due to uncontrolled use of innovations. New information can contribute to controlling both risks. We use the term "outcomes research" to describe the new working field that generates this information. The need for outcomes research is described. To differentiate clinical research from outcomes research, we demonstrate that these two fields of research pursue different goals, use different methods, and finally generate different types of results.

Emergency ultrasound-based algorithms for diagnosing blunt abdominal trauma

BACKGROUND

Ultrasonography is regarded as the tool of choice for early diagnostic investigations in patients with suspected blunt abdominal trauma. Although its sensitivity is too low for definite exclusion of abdominal organ injury, proponents of ultrasound argue that ultrasound-based clinical pathways enhance the speed of primary trauma assessment, reduce the number of computed tomography scans and cut costs.

OBJECTIVES

To assess the efficiency and effectiveness of trauma algorithms that include ultrasound examinations in patients with suspected blunt abdominal trauma.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, CENTRAL, CCMED, publishers' databases, controlled trials registers and the Internet. Bibliographies of identified articles and congress abstracts were handsearched. Trials were obtained from the Cochrane Injuries Group's trials register. Authors were contacted for further information and individual patient data.

PARTICIPANTS

patients with blunt torso, abdominal or multiple trauma undergoing diagnostic investigations for abdominal organ injury.

INTERVENTIONS

diagnostic algorithms comprising emergency ultrasonography (US).

CONTROLS

diagnostic algorithms without US ultrasound examinations (e.g. primary computed tomography [CT] or diagnostic peritoneal lavage [DPL]).

OUTCOME MEASURES

mortality, use of CT and DPL, cost-effectiveness, laparotomy and negative laparotomy rates, delayed diagnoses, and quality of life.

STUDIES

randomised controlled trials (RCTs) and quasi-randomised trials (qRCTs).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion, assessed methodological quality and extracted data. Where possible, data were pooled and relative risks (RRs), risk differences (RDs) and weighted mean differences, each with 95% confidence intervals (CIs), were calculated by fixed- or random-effects modelling, as appropriate.

MAIN RESULTS

We identified two RCTs with US in the experimental arm and another with US in the control group. We also considered two qRCTs. Overall, trials were of moderate methodological quality. Few authors responded to our written inquiries seeking to resolve controversial issues and to obtain individual patient data. We were able to pool data from two trials comprising 1037 patients for primary endpoint analysis (i.e. mortality). The relative risk in favour of the no-US arm was 1.4 (95% CI 0.94 to 2.08). Because of a lack of details, the meaning of this observation remains unclear. There was a marginal benefit with US-based pathways in reducing CT scans (random-effects RD -0.46; 95% CI -1.00 to 0.13), offset by trials of higher methodological rigour. No differences were observed in DPL and laparotomy rates.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to justify promotion of ultrasound-based clinical pathways in diagnosing patients with suspected blunt abdominal trauma.

Immunotherapy for advanced renal cell cancer

BACKGROUND

The course of advanced renal cell carcinoma is extremely variable, ranging from spontaneous remission to disease progression refractory to chemotherapy. Immunotherapy has held promise of improved outcomes based on uncontrolled studies and randomized controlled trials generally limited by small size and low power.

OBJECTIVES

To evaluate immunotherapy for advanced renal cell carcinoma by comparing: (1) high dose interleukin-2 to other options and (2) interferon-alfa to other options. The primary outcome of interest was overall survival at one year, with remission as the main secondary outcome of interest.

SEARCH STRATEGY

A systematic search of the CENTRAL, MEDLINE, and EMBASE databases was conducted for the period 1966 through end of December 2003. Handsearches were made of the proceedings of the periodic meetings of the American Urologic Association, the American Society of Clinical Oncology, ECCO - the European Cancer Conference, and the European Society of Medical Oncology for the period 1995 to June 2004.

SELECTION CRITERIA

Randomized controlled trials that selected (or stratified) patients with advanced renal cell carcinoma, utilized an immunotherapeutic agent in at least one study arm, and reported remission or survival by allocation. Fifty-three identified studies involving 6117 patients were eligible and all but one reported remission; 32 of these studies reported the one-year survival outcome.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted each article by following a prospectively designed protocol. Dichotomous outcomes for treatment remission (partial plus complete) and for deaths at one year were used for the main comparisons. Survival hazard ratios were also used for studies of interferon-alfa versus controls, and for two randomized studies of the value of initial nephrectomy prior to interferon-alfa in fit patients with metastases detected at the time of diagnosis.

MAIN RESULTS

Combined data for a variety of immunotherapies gave an overall chance of partial or complete remission of only 12.9% (99 study arms), compared to 2.5% in 10 non-immunotherapy control arms, and 4.3% in two placebo arms. Twenty-eight percent of these remissions were designated as complete (data from 45 studies). Median survival averaged 13.3 months (range by arm, 6 to 27+ months). The difference in remission rate between arms was poorly correlated with the difference in median survival so that remission rate is not a good surrogate or intermediate outcome for survival for advanced renal cancer. We were unable to identify any published randomized study of high-dose interleukin-2 versus a non-immunotherapy control, or of high-dose interleukin-2 versus interferon-alfa reporting survival. It has been established that reduced dose interleukin-2 given by intravenous bolus or by subcutaneous injection provides equivalent survival to high dose interleukin-2 with less toxicity. Results from four studies (644 patients) indicate that interferon-alfa is superior to controls (OR for death at one year = 0.56, 95% confidence interval 0.40 to 0.77). Using the method of Parmar 1998, the pooled overall hazard ratio for death was 0.74 (95% confidence interval 0.63 to 0.88). The weighted average median improvement in survival was 3.8 months. T he optimal dose and duration of interferon-alfa remains to be elucidated. The addition of a variety of enhancers, including lower dose intravenous or subcutaneous interleukin-2, has failed to improve survival compared to interferon-alfa alone. Two recent randomized studies have examined the role of initial nephrectomy prior to interferon-alfa therapy in highly selected fit patients with metastases at diagnosis and minimal symptoms: despite minimal improvement in the chance of remission, both studies of up-front nephrectomy improved median survival by 4.8 months over interferon-alfa alone. Recent studies have been examining anti-angiogenesis agents. A landmark study of bevacizumab, an anti-vascular endothelial growth factor antibody, was associated with significant prolongation of the time to progression of disease when given at high dose compared to low-dose or placebo therapy though frequency of remissions or survival were not improved.

AUTHORS' CONCLUSIONS

interferon-alfa provides a modest survival benefit compared to other commonly used treatments and should be considered for the control arm of future studies of systemic agents. In fit patients with metastases at diagnosis and minimal symptoms, nephrectomy followed by interferon-alfa gives the best survival strategy for fully validated therapies. The need for more effective specific therapy for this condition is apparent.

[Emergency ultrasound for blunt abdominal trauma--meta-analysis update 2003]

Emergency ultrasound has established itself as a key procedure of primary diagnostic work-up for blunt abdominal and multiple trauma. However, in a systematic review published in 2001 ultrasonography turned out to provide an unexpectedly low sensitivity. We conducted an update of this analysis to investigate if test characteristics will be maintained including recent studies. Prospective trials published between January 1957 and January 2003 were identified using the Medline/Oldmedline, Embase and Cochrane Controlled Trials Register databases. The searching strategy comprised a manual search as well as a search along the world-wide web. Qualitative rating was carried out by two investigators using criteria proposed by the Centre for Evidence-Based Medicine, Oxford. We investigated a composite endpoint (i. e., free fluid and/or organ laceration) as well as the single criteria organ injury and free intraabdominal fluid collections. After calculation of two-by-two-tables, Summary Receiver Operating Characteristics (SROC) and Q* values were determined together with their 95% confidence intervals. The Q* value was proposed as the point of intersection where sensitivity equals specificity. In addition, a random effects model was employed to compute common positive and negative likelihood ratios (LR). By assessing the title and/or abstract, 349 of 957 papers contained potentially valid information for the purpose of this review. A total of 67 studies were deemed eligible, nine of which had to be excluded from meta-analysis because of dual publication. This left 58 trials allocating 16,361 subjects for statistical analysis. Despite a trend towards improved study designs observed during the past decade, the included trials were of average methodological quality. Two-thirds of all investigations fulfilled two or less of the six possible quality criteria. The diagnostic reference standard was applied independently in only 40% of all protocols. With regard to the composite endpoint and the sonographic depiction of free fluid, the Q* value was estimated at 0.91, whereas Q* equaled 0.90 for the detection of organ injury. Q* values subsequently decreased with improving study quality and fell clearly below 0.80 in methodologically proper studies. Accounting for a negative LR of 0.23 (composite endpoint) and an assumed prevalence of 35% of intraabdominal injury, a post-test probability of 11% will remain in case of a negative sonogram. In pediatric trauma, ultrasound showed even worse test characteristics (negative LR = 0.43). Thus, in case of a 35% prevalence, the post-test probability has to estimated at 19%. Emergency ultrasound provides high specificity but insufficient sensitivity to reliably rule out intraabdominal injury.

A likelihood ratio approach to meta-analysis of diagnostic studies

OBJECTIVE

To develop a clinically and methodologically sound approach to diagnostic meta-analysis.

METHODS

Two-step model was used involving four fictitious sets of 10 studies each with varying sensitivity and specificity; this was followed by the application of the method to data from a published systematic review of emergency ultrasound. Multidimensional test characteristics (relating to the detection or exclusion of the condition of interest) were described by likelihood ratio scatterplots and pooled likelihood ratios. Likelihood ratios summarise the ability of a test to revise the prior probability of disease. They can be summarised by established fixed-effects and random-effects methods.

RESULTS

Likelihood ratios precisely describe both directions of test performance. By plotting positive against negative likelihood ratios, together with their 95% confidence intervals, a multidimensional forest plot is obtained that can be interpreted in analogy to therapeutic meta-analyses. There are accepted threshold values of positive and negative likelihood ratios (i.e. 10.0 and 0.1) to recommend a test for clinical use. In the matrix space, distinct test characteristics can even be assessed by eyeballing. With regard to data from the real meta-analysis, the suggested high discriminatory power of ultrasound was only partially qualified by likelihood ratios. The positive value confirms the reliability of a positive scan, whereas the negative value questions a normal sonogram.

CONCLUSIONS

A full characterisation of test performance requires multidimensional effect measures. Likelihood ratios are recommended descriptors of the two dimensions of diagnostic research evidence and provide a convenient means to visualise and to communicate results as weighted summary estimates of a diagnostic meta-analysis.

[Evidence-based medicine in orthopaedics - a sensible or unnecessary addition to clinical routine? Part 2: the therapy tool]

AIM

In the second part of our project to implement evidence-based medicine into day-to-day clinical practice the module therapy is presented.

METHODS

Within a teaching session in our department 20 participants guided by an extern al EBM teacher validated the results of an article according to the EBM criteria concerning the module therapy. To work with this module formal procedures are necessary, too.

RESULTS

Statistical tests to evaluate the relevance and validity of the chosen article were performed. The following data were determined: relative risk reduction, absolute risk reduction, number needed to treat.

CONCLUSION

In conclusion we can show, that EBM can help to solve day-to-day clinical problems, because the structured analysis concerning valid answers to concrete clinical problems is possible.

[Evidence-based medicine and anaesthesiology--six steps towards implementation into clinical practice]

Whenever evidence-based medicine (EbM) is mentioned among physicians, it evokes many different and contradictory reactions. On the one hand a lot of physicians have heard of this concept, but may hardly associate anything with it. On the other hand most of the physicians seem to be skeptical rather than in favour of evidence-based medicine. They seem to be concerned about restrictions in daily clinical decision-making or negative implications for the relationship between patient and physician. In this article we would like to deal with the question whether evidence-based medicine is useful for clinicians and which chances are provided for both the physicians and the patients by using it. First, the methodology and aims of evidence-based medicine are introduced. Second, by using an example of clinical anaesthesiology, we discuss the six formal steps for implementing this method. Third, important points which help to assess clinical studies are mentioned. In conclusion we would like to point out that evidence-based medicine is no entirely new concept of medicine but aims to highlight a solid and conscientious scientific basis of clinical decision-making. Thus, evidence-based medicine may act as a methodological strategy helping to clear the proceedings of decision-making and improve the provision of medical care to patients. Furthermore, it may guarantee a rapid transfer of knowledge from outcome-related research to patient care.

[Evidence-based medicine in orthopedics - a sensible or unnecessary addition to clinical routine? Part 1: the diagnostics tool]

AIM

The methods of evidence based medicine (EBM) are recommended to solve problems in day-to-day routine. Aim of this article is to demonstrate the practicability of this procedure for the diagnostic module.

METHODS

Within a teaching session in our department 20 participants guided by an extern al EBM teacher validated the results of an article according to the EBM criteria concerning the module "diagnosis". We demonstrate what EBM can contribute to solve day-to-day clinical problems and discuss the six formal steps for the implementation of EBM into day-to-day practice. 1) To transform the clinical problem into an answerable 4-part question. 2) To answer this question based on your internal evidence. 3) To search for external evidence to answer this question. 4) To critically appraise the evidence found with respect to its validity, importance and applicability. 5) To integrate the appraised external evidence into your existing internal evidence in order to come to a new decision if the additional new external evidence is convincing. 6) To assess the benefit which was gained for the patient.

RESULTS

Statistical tests to evaluate the relevance and validity of the chosen article were performed. The following data were determined: sensitivity, specifity, pretest probability, posttest probability, likelihood ratio, positive predictive value, negative predictive value.

CONCLUSION

In conclusion we show that EBM can help to solve day-to-day clinical problems, because the structured analysis of concrete questions can lead to a validation of the literature.

Comparison of German language versions of the QWB-SA and SF-36 evaluating outcomes for patients with prostate disease

BACKGROUND

The quality of well-being scale (QWB) and the Medical Outcome Study 36-item short form (SF-36) are alternative methods for measuring general health outcomes. Few studies compare these approaches against one another and no studies have compared German language versions.

METHOD

A German language version of the self-administered quality of well-being scale (QWB-SA) was developed using forward and back translation methods. The German QWB-SA and a German language version of the SF-36 were administered to clinical population groups with current diagnoses of prostate cancer, benign hyperplasia of the prostate, colon cancer, and rectal cancer. Data were obtained from four German clinics. In addition to the quality of life measures, data on cancer stage and disease state were obtained.

RESULTS

The QWB-SA and SF-36 were highly correlated. The QWB-SA was systematically related to disease state. Those with no symptomatic evidence had the highest scores followed by those who were stable with no metastatic disease and those with metastatic progression. Similar patterns were found for most SF-36 scales although the SF-36 failed to discriminate between those with no evidence of disease and those with stable disease without metastasis.

CONCLUSIONS

Both the QWB-SA and SF-36 perform as expected using German language translations. Although both measures differentiate patients with metastasis from those without symptoms, the QWB-SA better differentiated those with no evidence of disease from those with stable disease without metastasis.

Systematic review and meta-analysis of antibiotic therapy for bone and joint infections

We set out to evaluate the clinical efficacy of individual antibiotic agents for bone and joint infections in adults. Published and unpublished controlled trials reported between 1966 and 2000 were reviewed to determine if they involved random or quasi-random allocation to systemically administered antimicrobials or local antibiotic therapy for osteomyelitis and septic arthritis. Quiescence of infection after 1 year of follow-up was defined as the primary outcome measure. 22 trials containing 927 patients were eligible for final analysis. Varying proportions of the entire study population could be evaluated with respect to primary and secondary endpoints. Methodological quality was poor among most studies, and interpretability of results was further limited by small sample sizes, missing descriptions of patient populations and disease characteristics, and the frequent application of concomitant antibiotics. A trend towards improved, long-lasting infection control was observed in favour of a rifampicin-ciprofloxacin combination versus ciprofloxacin monotherapy for the treatment of staphylococcal infections related to orthopaedic devices (absolute risk difference [ARD] 28-9%; 95% CI -0.7 to 54.4%). Obviously unbalanced comparative studies showed some benefit of ticarcillin for bone infections caused by Pseudomonas species. No significant differences in therapeutic efficacy were found among trials comparing oral fluoroquinolones with intravenous beta-lactam drugs for both end-of-treatment (OR 0.8; 0.5 to 1.4) and long-term results (OR 1.3; 0.8 to 2.1). A variety of drugs was used as controls, thereby leading to inconsistent findings of drug-related side effects. Only one randomised trial was suitable to investigate the impact of polymethylmethacrylate gentamicin bead chains compared with parenteral antibiotics for skeletal infections, although this study was biased by patients receiving both combined local and systemic antibiotic therapy. Whereas intention-to-treat evaluation suggested a therapeutic advantage of systemic over local therapy, this trend diminished in the per-protocol analysis (1-year follow-up ARD -2.3;-17.5 to 10.8%). There exists little high-quality evidence on antibiotic therapy for osteomyelitis and septic arthritis. The observed heterogeneity among patient populations and medical and surgical treatment concepts preclude reliable inferences from the available data.

Systematic review and meta-analysis of emergency ultrasonography for blunt abdominal trauma

BACKGROUND

How precise and reliable is ultrasonography as a primary tool for injury assessment in blunt abdominal trauma?

METHODS

A systematic review and meta-analysis were conducted of prospective clinical trials of ultrasonography for blunt abdominal trauma. Publications were retrieved by structured searching among databases, review articles and major text books. Authors and experts in the field were contacted for original and unpublished data. For statistical analysis, summary receiver operating characteristic curves (SROCs) were computed using weighted and robust regression models, with Q* denoting the shoulder of the curve. Post-test probabilities were calculated as a function of pooled likelihood ratios (LRs).

RESULTS

Thirty of 123 trials enrolling 9047 patients were eligible for final analysis. With respect to targeting organ lesions, ultrasonography showed a summary Q* value of 0.91 (inverse variance weights, 95 per cent confidence interval (c.i.) 0.76-1.07); negative predictive values ranged from 0.72 to 0.99. A similar SROC slope was calculated for screening for free fluid (Q* = 0.89 (95 per cent c.i. 0.73-1.05)). Ultrasonography detects the presence of organ lesions, but fails to exclude abdominal injuries (random effects negative LR 0.23 (95 per cent c.i. 0.18-0.28)). Given a pretest probability of 50 per cent for blunt abdominal injury, a post-test probability of nearly 25 per cent remains in the case of a negative sonogram.

CONCLUSION

Despite its high specificity, ultrasonography has an unexpectedly low sensitivity for the detection of both free fluid and organ lesions. In clinically suspected abdominal trauma, another assessment (e.g. helical computed tomography) must be performed regardless of the initial ultrasonographic findings.

[Evidence-based medicine in ENT]

Using a clinical example we discuss the reasons why some of our colleagues associate unpleasant feelings with the term Evidence-Based Medicine (EBM). We demonstrate what EBM can contribute to solve day-to-day clinical problems and discuss the six formal steps for implementation of EBM into the day-to-day practise. 1. To transform the clinical problem into an answerable 4-part question. 2. To answer this question based on your internal evidence. 3. To search for external evidence to answer this question. 4. To critically appraise the found evidence with respect to it's validity, importance and applicability. 5. To integrate the appraised external evidence into your existing internal evidence in order to come to a new decision if the additional new external evidence in convincing. 6. To assess the benefit which was gained for the patient.

[Challenge of evidence-based medicine: sense and non-sense of diagnostic tests in gynecology]

Evidence-based medicine is the synthesis of internal evidence (experience) and best external evidence (literature) aiming to solve a particular clinical problem. This paper gives an overview on different tools to appraise rationales and results of diagnostic tests such as CA-125 monitoring in patients with ovarian cancer.

[Function of evidence-based medicine in general practice. Case report: streptococcal pharyngitis]

A Bavarian country doctor taking part in a course on evidence-based medicine, put the question whether there was any evidence that, in children with confirmed streptococcal infection of the respiratory tract, appropriate antibiotic treatment could reduce the risk of late complications. With the help of the German Institute for Medical Documentation and Information (DIMDI), we undertook a search of the literature, which, however, failed to turn up any information in support of a prophylactic effect of antibiotic treatment in such a case. To avoid jumping to hasty conclusions, however, the consequences that appear to suggest themselves, should be carefully considered. This example points up three major aspects of evidence-based medicine (attitude, tools and facts) that the doctor needs to acquire, and without which modern medicine will not be possible.

p53 mutations in hairy cell leukemia

We have studied the frequency of p53 mutations in genomic DNA extracted from peripheral blood or the spleen of 61 patients with hairy cell leukemia using PCR-SSCP and automated cycle sequencing. We identified exon 5-8 mutations in 17 cases, corresponding to a frequency of 28%. In four cases, mutations were localized in exon 5; one patient with atypical HCL had a mutation in exon 6 at the 3' boundary; five cases showed mutations in exon 7, while exon 8 was found to be mutated in seven cases. The mutations found could be divided into three major categories: structural (n=9), inactivating (n= 6), and neutral (n= 2) mutations. None of the three transitions found occurred at CpG dinucleotides. The rate of p53 mutations found in this large cohort of HCL patients is unexpectedly high as in other non-Hodgkin lymphomas p53 mutations predict for poor treatment outcome. The character of the mutations we have found is entirely different from that described in other hematologic malignancies.

[Guidelines from the viewpoint of clinical economics]

In an experiment that compared the quality of medical guidelines in German cancer centers we were able to demonstrate that the selection of guidelines was not based on common criteria. These decisions were frequently based on personal preferences rather than on scientific evidence. We should consider that the scientific quality of clinical publications is easily assessed by simple methods in two dimensions, effectiveness and efficiency. This subsequently led to three conclusions: Clinical epidemiology/evidence-based medicine should be integrated into medical education. Interdisciplinary co-operation to create "common criteria for guidelines" should be supported. Politicians have the responsibility to provide the legal framework in order to ensure self administration in health care.

[Implementing evidence-based medicine: what effects are measurable?]

Evidence-based medicine (EBM) was proposed as a possible method of solving two of health care's present problems: the increasing flood of information and rising expenditures. Although this concept appears to be plausible, the measurable improvements in health care brought about by possible implementation of EBM should be explicitly described. After having demonstrated the present problems as well as the necessity to solve them, we described the goals intended to be achieved by the implementation of EBM. Furthermore, the impact of EBM on medical education was described. The possible influence of EBM on the effectiveness and efficiency of health care was also considered. The conflicts caused by the introduction of EBM were demonstrated using the example of the "German Guideline Discussion". Finally, three proposals were made; the integration of EBM into education, the avoiding of conflicts similar to the German Guideline Discussion and the need to alter the political framework accompanying these processes.