The historical development of clinical therapeutic trials

Methodological Issues Relevant to Blinding in Physical Medicine and Rehabilitation Research

ABSTRACT

Blinding in research is important, and the field of physical medicine and rehabilitation poses special consideration owing to the patient populations and treatment methodologies used. Historically, blinding has been increasingly relevant to conducting good-quality research. The main reason to blind is to reduce bias. There are several strategies to blinding. At times, when blinding is not possible, alternatives to blinding include sham control and description of study and control groups. Illustrative examples of blinding used in physical medicine and rehabilitation research are described in this article, along with how to assess success and fidelity of blinding.

Barriers and facilitators to the participation of subjects in clinical trials: An overview of reviews

BACKGROUND

The demand for clinical trial participants is today one of the highest it has ever been and continues to increase. At the same time, subject recruitment continues to be problematic and the major reason for clinical trial premature terminations. The literature on clinical trial recruitment, which spans several decades and includes hundreds of studies, has an abundance of findings that can be synthesized by way of an overview to provide a well-informed and complete picture of the factors that determine subject participation.

OBJECTIVES

An overview of the systematic reviews that report barriers and facilitators to clinical trial participation was conducted. The extracted data were synthesized, and a thematic framework of the factors that affect subject participation in clinical trials was developed. The overview extended across medical subjects and demographics.

METHODS

Thirty reviews that complied with the inclusion criteria were included. These reviews covered 753 relevant primary studies and reported 881 barriers and facilitators. The barriers and facilitators were thematically synthesized and a thematic framework of 20 themes was developed. The quality of the included reviews was assessed and reported.

MAIN RESULTS

Several opportunities to increase clinical trial participation, by developing interventions and changing the trial design, derived from an analysis of the thematic framework. That analysis also showed that most of the 20 themes operate mainly as a barrier or as a facilitator, and that most have an effect across medical subjects. As to the quality elements assessed, some reviews complied almost fully but most only partially.

Classification and Production of Polymeric Foams among the Systems for Wound Treatment

This work represents an overview on types of wounds according to their definition, classification and dressing treatments. Natural and synthetic polymeric wound dressings types have been analyzed, providing a historical overview, from ancient to modern times. Currently, there is a wide choice of materials for the treatment of wounds, such as hydrocolloids, polyurethane and alginate patches, wafers, hydrogels and semi-permeable film dressings. These systems are often loaded with drugs such as antibiotics for the simultaneous delivery of drugs to prevent or cure infections caused by the exposition of blood vessel to open air. Among the presented techniques, a focus on foams has been provided, describing the most diffused branded products and their chemical, physical, biological and mechanical properties. Conventional and high-pressure methods for the production of foams for wound dressing are also analyzed in this work, with a proposed comparison in terms of process steps, efficiency and removal of solvent residue. Case studies, in vivo tests and models have been reported to identify the real applications of the produced foams.

Polio, AIDS, and Ebola: A Recurrent Ethical Dilemma

During the 2014 West African outbreak, a dilemma emerged about the ethics of conducting randomized placebo-controlled trials in the midst of a rapidly spreading, devastating epidemic for which there was no effective treatment. The dilemma has in fact has deep historic roots; it has appeared in several previous fearsome epidemics-during the poliomyelitis epidemic in the 1930s-1950s, and again during the AIDS epidemic in the1980s-1990s. Moreover, ethical and social questions characterizing each of these epidemics-the increased risks of withholding potentially life-saving drugs for people assigned to a control arm and the damaging effect on eroding community trust-were conceptualized beforehand in the 1925 novel Arrowsmith. A historical analysis both reaffirms that rigorous placebo-controlled trials remain indispensable tools in epidemic settings and also provides guidance on how to approach the ethical and social issues that will likely arise when these trials are carried out in future epidemic emergencies.

Exploring the roots of clinical trial methodology in medieval Islamic medicine

There is a dominant opinion in the Western sources of history of medicine that the roots of modern clinical trials and methodology of experimental medicine first started in the Renaissance. However, this opinion has been disputed with the thorough study of the rich medical literature of the medieval Islamic era. In the current review, the roots of clinical trial methodology have been traced back to the medieval Islamic tradition and the contribution of Islamic scholars in this field is discussed. The importance of experimental versus theoretical reasoning, the need for a control group, a statistical approach to interpreting trial results, appreciation of uncertainty in medical practice, and the difference between human and animal trials all can be traced back to the rich medieval Islamic medical literature.

Why Ineffective Psychotherapies Appear to Work: A Taxonomy of Causes of Spurious Therapeutic Effectiveness

The past 40 years have generated numerous insights regarding errors in human reasoning. Arguably, clinical practice is the domain of applied psychology in which acknowledging and mitigating these errors is most crucial. We address one such set of errors here, namely, the tendency of some psychologists and other mental health professionals to assume that they can rely on informal clinical observations to infer whether treatments are effective. We delineate four broad, underlying cognitive impediments to accurately evaluating improvement in psychotherapy-naive realism, confirmation bias, illusory causation, and the illusion of control. We then describe 26 causes of spurious therapeutic effectiveness (CSTEs), organized into a taxonomy of three overarching categories: (a) the perception of client change in its actual absence, (b) misinterpretations of actual client change stemming from extratherapeutic factors, and (c) misinterpretations of actual client change stemming from nonspecific treatment factors. These inferential errors can lead clinicians, clients, and researchers to misperceive useless or even harmful psychotherapies as effective. We (a) examine how methodological safeguards help to control for different CSTEs, (b) delineate fruitful directions for research on CSTEs, and (c) consider the implications of CSTEs for everyday clinical practice. An enhanced appreciation of the inferential problems posed by CSTEs may narrow the science-practice gap and foster a heightened appreciation of the need for the methodological safeguards afforded by evidence-based practice.

[Status of clinical trials in oncology--2013 and onwards]

Clinical trials connect basic science with patient care. They form the backbone of evidence-based medicine and clinical guidelines. The unprecedented implementation of new methods in oncology over the past 40 years has only been possible on the basis of multiple well-organized clinical study groups. The continued existence of these study groups in their current multitude is in danger. Far-reaching changes in the legal framework, underfunding, new definitions of patient-related outcome and shifts in the organization of cancer patient care ask for critical reappraisal and new concepts.

Assessing research impact in academic clinical medicine: a study using Research Excellence Framework pilot impact indicators

BACKGROUND

Funders of medical research the world over are increasingly seeking, in research assessment, to complement traditional output measures of scientific publications with more outcome-based indicators of societal and economic impact. In the United Kingdom, the Higher Education Funding Council for England (HEFCE) developed proposals for the Research Excellence Framework (REF) to allocate public research funding to higher education institutions, inter alia, on the basis of the social and economic impact of their research. In 2010, it conducted a pilot exercise to test these proposals and refine impact indicators and criteria.

METHODS

The impact indicators proposed in the 2010 REF impact pilot exercise are critically reviewed and appraised using insights from the relevant literature and empirical data collected for the University of Oxford's REF pilot submission in clinical medicine. The empirical data were gathered from existing administrative sources and an online administrative survey carried out by the university's Medical Sciences Division among 289 clinical medicine faculty members (48.1% response rate).

RESULTS

The feasibility and scope of measuring research impact in clinical medicine in a given university are assessed. Twenty impact indicators from seven categories proposed by HEFCE are presented; their strengths and limitations are discussed using insights from the relevant biomedical and research policy literature.

CONCLUSIONS

While the 2010 pilot exercise has confirmed that the majority of the proposed indicators have some validity, there are significant challenges in operationalising and measuring these indicators reliably, as well as in comparing evidence of research impact across different cases in a standardised manner. It is suggested that the public funding agencies, medical research charities, universities, and the wider medical research community work together to develop more robust methodologies for capturing and describing impact, including more valid and reliable impact indicators.

Experimental medicine 1000 years ago

Little is known about the state of experimentation in the field of medicine during the Medieval Islamic era. With few exceptions, most of the contemporary sources on history of medicine propagate the idea that the roots of experimental medicine in its modern form, including clinical trials and drug-potency studies, first started during the European Renaissance in the 16^th to the 18^th centuries. This study is part of an ongoing multidisciplinary primary-source investigation of the original Arabic works of 11 Islamic medical scholars who lived and practiced between the 9^th and the 13^th centuries. The study critically evaluated and documented their contributions to the development of the scientific method and experimental medicine during that medieval Islamic era in several areas including critical appraisal of previous knowledge, clinical observations and case reports, clinical therapeutic trials, drug potency trials, experimentation on animals, dissection and dissection experiments as well as postmortem examinations. In each of the above-mentioned areas, significant contributions were made during the Medieval Islamic era from as early as the ninth century AD.

Stem cell transplantation in children: how to design a new study

In contrast to adults, 50% or more of medicines used in children have never been actually studied in the paediatric population in the European Union community (EU). Under the impression that compliance with good clinical practice (GCP) requirements will lead to an improved quality of clinical trials, the ratification of the EU Directive 2001/20/EG now imposes the same GCP regulations demanded for commercial clinical trials on non-commercial trials or so-called investigator-initiated trials (IITs). Although it is desirable that all clinical trials comply with ICH-GCP, ensuring that an IIT conforms creates a significant burden for the principal investigator, turning an IIT into a substantial logistic, administrative and financial enterprise. This can only be achieved with a multidisciplinary approach, including physicians, statisticians, data managers, administrators and others. In particular, 'treatment optimization studies'--the most important clinical trials in paediatric oncology--are affected by this new law, potentially resulting in significant delays in the implementation of new and innovative treatment strategies in the paediatric population. This significant drawback was not foreseen but is now recognized and lead to measures to improve the situation for both non-commercial and paediatric clinical trials. Draft guidance on 'specific modalities for non-commercial trials', posted for comment last October, attempts to redress some of the research-crippling problems caused by the initial legislation; however, major problems remain. The EU regulation (EC) no. 1901/2006 'on medicinal products for paediatric use' was enacted in January 2007. This new regulation is a promising step in the right direction, as it will facilitate the development and accessibility of medicinal products specifically for use in children. To adapt to and benefit from this new situation and encourage IIT, a coordinated approach of high expertise is necessary to support and guide the novice in the field of IIT to successfully launch, conduct and complete clinical trials especially in children.

The Kendrick-Eldering-(Frost) pertussis vaccine field trial

Additional material for this article is available from the James hind Library website [ http://www.jameslindlibrary.org ], where this article was previously published.

[20th century at a glance: the streptomycin story]

The discovery of streptomycin is attributed to a microbiologist, Selman Waksman, Nobel Prize 1952, a paternity that was disputed by his collaborator Albert Schatz, who was the first author of the princeps article. Two pioneering clinical studies involved streptomycin, both of which have been widely used as reference works. The first one was English, under the name of Austin Bradford Hill. It inaugurated a randomization in medicine. The second trial was American, and carried out by the Veteran Administration. It made use for the first time of the "control group". The present article analyses the genesis of clinical trials and illustrates the recurrent difficulties encountered in their implementation.

Reporting of Randomized Controlled Trials in Hodgkin Lymphoma in Biomedical Journals

BACKGROUND

Randomized controlled trials (RCTs) are the best tool to evaluate the effectiveness of clinical interventions. The Consolidated Standards for Reporting Trials (CONSORT) statement was introduced in 1996 to improve reporting of RCTs. We aimed to determine the extent of ambiguity and reporting quality as assessed by adherence to the CONSORT statement in published reports of RCTs involving patients with Hodgkin lymphoma from 1966 through 2002.

METHODS

We analyzed 242 published full-text reports of RCTs in patients with Hodgkin lymphoma. Quality of reporting was assessed using a 14-item questionnaire based on the CONSORT checklist. Reporting was studied in two pre-CONSORT periods (1966-1988 and 1989-1995) and one post-CONSORT period (1996-2002).

RESULTS

Only six of the 14 items were addressed in 75% or more of the studies in all three time periods. Most items that are necessary to assess the methodologic quality of a study were reported by fewer than 20% of the studies. Improvements over time were seen for some items, including the description of statistics methods used, reporting of primary research outcomes, performance of power calculations, method of randomization and concealment allocation, and having performed intention-to-treat analysis.

CONCLUSIONS

Despite recent improvements, reporting levels of CONSORT items in RCTs involving patients with Hodgkin lymphoma remain unsatisfactory. Further concerted action by journal editors, learned societies, and medical schools is necessary to make authors even more aware of the need to improve the reporting RCTs in medical journals to allow assessment of validity of published clinical research.

Emergence of quantification in clinical investigation and the quest for certainty in therapeutics: the road from Hammurabi to Kefauver

Throughout most of history, medical knowledge was descriptive in nature and derived from the work of individual investigators of independent mind pursuing careful but often chance observations. Using deductive reasoning, these findings were then generalized, authoritatively presented, and dogmatically promulgated. This, coupled with firmly grounded principles of divine determinism, precluded any serious consideration of randomness, even when variations from recorded, but erroneous, statements were actually observed. Although probability remained an integral component of diagnosis and therapy, it was only as an attribute of opinion and not one supported by numbers. The gradual erosion of this edifice began during the scientific revolution of the seventeenth century that led to the burgeoning of the sciences basic to medicine. Although clinicians applauded these contributions, they failed to apply the inductive method of investigation to the study of disease or to therapy. The "numerical method" of Pierre Louis (1787-1872) first introduced systematic quantification into medicine during the first half of the nineteenth century. Analysis of quantifiable data found its principal application in epidemiology, which flourished during the second half of the nineteenth century. The subsequent adoption of probability calculus for the analysis of quantifiable data, during the first half of the twentieth century, refined the process further and led to the gradual emergence of medical statistics, with a distinct role in clinical research. The mathematical precision provided by quantification and statistical analysis established certainty in medicine and ultimately changed the conjectural art of clinical practice into a disciplined science founded on clinical investigation, the very basis of present-day, evidence-based medicine.

The classic caries clinical trial: constraints and opportunities

The history of clinical trials would include events in 1747 on board the Salisbury, a British Navy vessel at sea with 12 seamen critically ill with scurvy. Involving these 12 sailors in a study, an officer on board by the name of Lind evaluated six potential treatments for scurvy, and rapidly reached the conclusion that daily consumption of citrus fruits returned the men fit for duty in approximately six days (Bull, 1959). The concept of experimental randomization was first developed by Sir R.A. Fisher (1925, 1926), and the method was introduced to medical research via a study of tuberculosis treatment by Amberson and co-workers (1931), who randomized 24 TB patients into two groups, one to receive the experimental therapy, the other serving as the control. Amberson et al. also incorporated the concept of blinding into their study. Sir Austin Bradford Hill codified and built on the principles of scientific experimentation developed by Fisher, and introduced the use of random numbers in the allocation of patients in the British Medical Research Council (1948) study of the effect of streptomycin in the treatment of tuberculosis (Daniels and Hill, 1952; Hill, 1952). The first applications of clinical trial methodology for testing interventions on dental, oral, and maxillofacial diseases and conditions are more difficult to determine. For dental caries prevention, however, Chilton and Fertig (1958) and Slack and Martin (1964) were certainly among the early caries clinical trial pioneers. As clinical trials have come into the mainstream of clinical research in medicine and dentistry, a great deal of developmental work has focused on their methodological enhancement. The most successful of these efforts have come from fruitful, ongoing collaborations among clinician investigators, biostatisticians, data management specialists, biomedical ethicists, and others with an academic interest in clinical trial design and utilization. During the past 25 years, the emergence of systematic reviews and the evidence-based medicine (EBM) movement have also contributed significantly to the increasing reliance on randomized clinical trial outcomes for the advancement of better clinical practice (Richards et al., 1997; Straus and Sackett, 1998; www.cochrane.org/cochrane/ccbroch.htm#BDL, 2002).

The randomised controlled trial design: unrecognized opportunities for health sciences librarianship

OBJECTIVE

to describe the essential components of the Randomised Controlled Trial (RCT) and its major variations; to describe less conventional applications of the RCT design found in the health sciences literature with potential relevance to health sciences librarianship; to discuss the limited number of RCTs within health sciences librarianship.

METHODS

narrative review supported to a limited extent with PubMed and Library Literature database searches consistent with specific search parameters. In addition, more systematic methods, including handsearching of specific journals, to identify health sciences librarianship RCTs.

RESULTS

While many RCTs within the health sciences follow more conventional patterns, some RCTs assume certain unique features. Selected examples illustrate the adaptations of this experimental design to answering questions of possible relevance to health sciences librarians. The author offers several strategies for controlling bias in library and informatics applications of the RCT and acknowledges the potential of the electronic era in providing many opportunities to utilize the blinding aspects of RCTs. RCTs within health sciences librarianship inhabit a limited number of subject domains such as education. This limited scope offers both advantages and disadvantages for making Evidence-Based Librarianship (EBL) a reality.

CONCLUSIONS

The RCT design offers the potential to answer far more EBL questions than have been addressed by the design to date. Librarians need only extend their horizons through use of the versatile RCT design into new subject domains to facilitate making EBL a reality.

Clinical trials - from anecdotes to evidence based medicine

Treatments based on theory and anecdote with extravagant public claims without being properly tested has become past time in medical practice. Only valid unbiased and relevant evidence obtained by methodology of clinical trials should be adopted in medical practice and practice guidelines. In such way clinical decisions are based on evidence rather than on authority. Inevitable part of clinical trials is medical ethics formally defined within the Nuremberg Code, World Medical Association Declaration of Helsinki and guidelines issued by the U.S. Department of Health, Education and Welfare. This paper presents in short history of clinical trials and current status worldwide.

The cystic fibrosis therapeutics development network (CF TDN): a paradigm of a clinical trials network for genetic and orphan diseases

Clinical trials have become critical to the advancement of medical science and to the evolution of patient care in medicine. The science of clinical research has advanced from early studies in which treatment was assessed without controls to sophisticated multinational collaborative randomized, double-blind, placebo controlled trials of therapeutic interventions. To facilitate the advancement of clinical research, clinical trials networks have been developed to conduct multicenter studies. This review describes the history of clinical trials, clinical trials networks, and the goals of such networks in the United States. The Cystic Fibrosis Therapeutics Development Network, a network that represents the paradigm for genetic and orphan diseases, is described in detail. This network has been extremely successful in its first 3.5 years of existence conducting 18 different clinical trials in patients with Cystic Fibrosis. Unique aspects of the network include the use of internet applications for study conduct and communication, the development of statistical methodology to enhance the efficiency of clinical trial design, the development of outcome measures specific to Cystic Fibrosis, and the development of infrastructure necessary for expediting protocol development. In the current environment, clinical research faces significant challenges related to ensuring the safe and ethical conduct of clinical research while promoting fast and efficient clinical trials. To succeed and move forward to provide treatments and find cures for diseases, clinical trials networks must continue to evolve. The Cystic Fibrosis Therapeutics Development Network represents a network that has met this challenge and will continue to provide a venue for the safe and efficient conduct of clinical trials in Cystic Fibrosis.

Evaluation of interventions

The first modern randomized controlled trial was published in 1948, and featured randomly allocated treatment groups, blinded outcome assessment, and a sufficient number of patients. Randomized controlled trials are now accepted as the best possible way to assess the effects of clinical interventions, but good trials sometimes disagree. Although the elements of a credible trial have been defined, the relative importance of these elements to results is not known. Information from clinical trials may be difficult to use in the care of patients if trial outcomes are not patient centered or the conditions of the trial are very different from the situation in clinical practice. Observational studies are often, but not always, an adequate substitute from randomized trials. Systematic reviews with meta-analyses may reveal patterns of results when individual trials do not, and so complement the information content of large trials. When trials disagree, resolution may be found not by from more trials but also from critical appraisal of individual trials, weighing the totality of the evidence, and Bayesian reasoning.

Treatment of heart failure according to William Stokes: the enchanted mercury

BACKGROUND

It was not until 1919 that the diuretic properties of mercury were observed in patients with syphilis; in the same year the beneficial effects of mercurial diuretics were shown in a patient with severe rheumatic heart disease and anasarca. However, mercury had been used much earlier for the treatment of dropsy without clear guidelines. In this article we describe William Stokes' insights into the treatment of heart failure, focusing on the beneficial diuretic properties of mercury.

METHODS

We reviewed the chapter "Treatment of the Weak and Probably Dilated Heart in Connexion With Enlargement of the Liver and Pulmonary Disease" in William Stokes' famous treatise The Diseases of the Heart and the Aorta.

CONCLUSIONS

Stokes makes several important clinical observations. First, he provides precise guidelines on when and how to use mercury in these patients. Second, he realizes the importance of mercury for the treatment of decompensated heart failure. Stokes recognizes the cyclical nature of frequent decompensation in congestive heart failure, the relationship of clinical deterioration and reduced urine output, and the importance of reestablishing urinary flow to ameliorate dyspnea. Third, he attempts to define the mechanism of action "... if any of the characteristic action of mercury can be perceived unless we include diuresis." Finally, he gives interesting guidelines on the dosage and side effects of mercury. These observations on the treatment of "congestive" heart failure are an important contribution to the understanding of heart failure pathophysiology and the design of prescription regimens for this disease.

Prospective randomized trials affect the outcomes of intraabdominal infection

OBJECTIVE

To compare the characteristics and outcomes of patients with intraabdominal infections enrolled in prospective randomized trials (PRTs) with those of a cohort of patients not enrolled in a trial.

SUMMARY BACKGROUND DATA

Prospective randomized trials are the gold standard for the evaluation of new treatments. Patients are screened using rigorous eligibility criteria and sometimes are excluded from PRTs because of associated medical conditions or more severe illness. However, the effect that the exclusion of these patients has on the applicability of clinical trial outcomes has not been defined.

METHODS

One hundred sixty-eight adults with intraabdominal infection were treated at a single institution during 7 years. Fifty-three patients were enrolled in four PRTs comparing various antibiotic regimens for treatment; 115 were not enrolled. Patient characteristics and outcomes of these two groups were compared.

RESULTS

Patients with infections from appendicitis (n = 68) had a low severity of illness and similar outcomes in both groups. These patients and those for whom a concurrent PRT was unavailable were excluded from subsequent analysis. Eighty-eight patients (42 PRT, 46 not enrolled) with serious infection remained for analysis. Patients enrolled in PRTs were younger, had less severe illness, had a decreased length of stay, a lower incidence of antibiotic resistance, and less frequent extraabdominal infections than those not enrolled in a trial. Patients enrolled in PRTs were more likely to be cured and were less likely to die. Logistic regression analysis demonstrated that cure was associated with a lower initial severity of illness, absence of antibiotic resistance, and participation in a PRT.

CONCLUSIONS

Patients with intraabdominal infection enrolled in PRTs have an increased likelihood of cure and survival. This is due in part to a lower incidence of antibiotic resistance, which may reflect improved drug selection. Patients not enrolled in PRTs are at greater risk for treatment failure and death because of concomitant illness. Outcomes from PRTs may not be applicable to all patients with intraabdominal infections.

Proof and policy from medical research evidence

When judging the benefits and harms of health care and predicting patient prognosis, clinicians, researchers, and others must consider many types of evidence. Medical research evidence is part of the required knowledge base, and practitioners of evidence-based medicine must attempt to integrate the best available clinical evidence from systematic research with health professionals' expertise and patients' rights to be informed about diagnostic and therapeutic options available to them. Judging what constitutes sound evidence can be difficult because of, among other things, the sheer quantity, diversity, and complexity of medical evidence available today; the various scientific methods that have been advanced for assembling, evaluating, and interpreting such information; and the guides for applying medical research evidence to individual patients' situations. Recommendations based on sound research can then be brought forward as either guidelines or standards, and criteria exist by which valid guidelines and standards can be developed and promulgated. Nonetheless, gaps and deficiencies exist in current guidelines and in the methods for finding and synthesizing evidence. Interpreting and judging medical research involves subjective, not solely explicit, processes. Thus, developments in evidence-based medicine are an aid, but not a panacea, for definitively establishing benefits and harms of medical care, and the contributions that medical research evidence can make in any clinical or legal situation must be understood in a context in which judgment and values, understanding of probability, and tolerance for uncertainty all play a role.

Epidemiologic evidence and causal inference

Preventing cancer depends on the ability to recognize and remove causal factors. In current practice, the methods used to judge cause from epidemiologic, clinical trials and biologic evidence include systematic narrative reviews, criteria-based inference methods, and meta-analysis. Subjectivity and values play a key role in the practice of causal inference, especially in selecting criteria and assigning rules of evidence to those criteria. Judging cause is a central concern of physicians, epidemiologists, and other public health professionals committed to cancer prevention.

Ethical lessons learned from the use of therapeutic plasma exchange in neurologic disease

Conflicts of interest are inherent in the practice of medicine, particularly in the conduct of clinical research. Such conflicts can often be identified and even resolved by the application of ethical principles as an integral part of such research. The opportunity to participate in a series of controlled clinical trials of therapeutic plasma exchange (TPE) in diverse neurologic disease provided an insight into some of the ethical dilemmas posed by such conflicts of interest. Chief among these was the recognition that informed consent is a precious though fragile and multidimensional concept. In the last analysis, ethics is the "business of being human"; respect for its guidance helps to ensure the success of clinical research.

Fifty landmark discoveries in gastroenterology during the past 50 years. A brief history of modern gastroenterology at the millennium: Part II. Gastrointestinal motility, nutrition, and diseases of the lower gastrointestinal tract, liver, and pancreas

During the last half century, many outstanding discoveries have revolutionized the clinical practice and science of gastroenterology. Although the scientific results are widely disseminated, the discoverers have received inadequate recognition and the history of their discoveries is largely unstudied and unknown. At the millennium, a committee selected 50 landmark discoveries in gastroenterology during the past 50 years. A brief history of each landmark discovery is presented. Part I was presented in the previous issue of Gastroenterology Clinics of North America. Part II presents landmark discoveries in gastrointerintal (GI) motility, clinical trials, nutrition, and diseases of the lower GI tract, liver, biliary tree, and pancreas.

The use of placebo control groups in the assessment of psychiatric drugs: an historical context

The reliable evaluation of treatments intended for the management of psychiatric illness would not be possible without the use of placebo. Other types of control groups can provide useful information, but none are capable of adducing a finding as compelling and unambiguously interpretable as a statistically significant drug-placebo difference. Its epistemological advantage notwithstanding, the ethicality of employing a placebo control group has been increasingly challenged in recent years. Many who object to the use of placebo on ethical grounds assume, incorrectly, that there are fungible alternatives to the use of placebo in the assessment of psychotropic drugs. This essay attempts to explain, within an historical context, not only why placebo is irreplaceable, but why it is often so difficult to communicate its advantages to those unfamiliar with the epistemological aims and methods of controlled clinical trials.

Likelihood and clinical trials

The history of the application of statistical theory to the analysis of clinical trials is reviewed. The current orthodoxy is a somewhat illogical hybrid of the original theory of significance tests of Edgeworth, Karl Pearson, and Fisher, and the subsequent decision theory approach of Neyman, Egon Pearson, and Wald. This hegemony is under threat from Bayesian statisticians. A third approach is that of likelihood, stemming from the work of Fisher and Barnard. This approach is illustrated using hypothetical data from the Lancet articles by Bradford Hill, which introduced clinicians to statistical theory.

Threats to validity in randomized clinical trials

The purposes of this article are to present an overview of randomized clinical trials (RCTs) and describe some of the methodological problems inherent in using RCTs in nursing research. Many nursing intervention studies are fraught with problems that defy the stringent control criteria required for RCTs, leading to biased estimates of intervention efficacy. Five threats to validity in RCTs are presented, including problems related to (a) differential dropout, (b) random assignment, (c) identifying and maintaining an adequate control condition, (d) nonadherence to research protocols, and (e) assessment of clinically meaningful change. Three strategies are recommended for addressing some of the problems posed by RCTs and improving inference.

Clinical testing of restorative materials: some historical landmarks

OBJECTIVES

The aim of the study was to review the historical background of the methodologies currently in use for clinical investigations of contemporary tooth coloured dental restorative materials and techniques, and to attempt to identify the likely general direction of such research projects in the future.

DATA SOURCES

Published articles obtained as a result of a wide ranging literature search of both dental and medical journals.

STUDY SELECTION

Historical and contemporary accounts of clinical trial management, upon which an overview of the key events important in the evolution of clinical methods of evaluation of dental restorative materials, and a prediction of possible future trends in this area, could be based.

CONCLUSIONS

Publication of dental restoratives clinical research has not kept up with that in medicine, where editors of leading journals require that clinical trials be run in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines. The current trend towards evidence based treatment in dentistry can be expected to initiate more statistically powerful clinical studies of dental restoratives, and the merit of involving general dentists in practice based research can also be anticipated to become increasingly recognised in the future.

[Clinical studies in oncology. Relevance, design, ethical considerations]

BACKGROUND

Clinical research in oncology includes the evaluation of diagnostic, prognostic and therapeutic parameters in order to establish standards for the different tumor entities. Prerequisite is the retrospective and prospective analysis of large patient groups with established statistical methods. New potentially better strategies have to be compared in randomised studies with the respective "gold standard". The central role of clinical studies for evaluation and optimisation of therapy can be considered as moral obligation to included the maximal possible number of patients in clinical studies. However, only a small number of tumor patients in Germany is treated in controlled clinical studies. Reasons are lack of organisational structures, but also ethical considerations.

STUDY DESIGNS

In this article several models for clinical studies are discussed with respect to their statistical significance, indication, and potential ethical objections.

CONCLUSION

Aim of the discussion is to increase the acceptance of the necessity of clinical studies for evaluation and optimisation of therapeutic options in oncology.

Clinical research in neurology. From observation to experimentation

Clinical research in neurology may be based on observation or intervention. Basic science and observational clinical studies often address questions of cause and pathogenesis, whereas interventional clinical experiments normally are required to establish the safety, tolerability, and efficacy of therapies. This article outlines various study paradigms and discusses the concepts of intervention, randomization, blinding, and control in the context of clinical trial design. Accurate interpretation of trial results is predicated on the care with which experimental therapeutic studies are designed and conducted.