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Results for “Randomized Controlled Trials as Topic”

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PubMed1989

The "trials" of a long-term clinical trial: the Ticlopidine Aspirin Stroke Study and the Canadian-American Ticlopidine Study.

The Ticlopidine Aspirin Stroke Study (TASS) and the Canadian-American Ticlopidine Study (CATS) were established by the Syntex Corporation to evaluate the potential efficacy of the antiplatelet agent ticlopidine. TASS was designed to address the use of the drug in the prevention of stroke in patients who had been diagnosed as having had one or more transient ischemic attacks (TIAs), using aspirin as a positive control. CATS was designed as a placebo-controlled trial to evaluate the drug's usefulness in prevention of a second stroke in patients after an initial stroke. Both studies were established in a "triple-blind" fashion where the patients, investigators, and Syntex were unaware of the patient assignments as to ticlopidine or control. In order to monitor the studies for potential toxicity/efficacy, Syntex established a "Safety Committee." The presentation describes, from the viewpoint of the Safety Committee, some of the issues raised by the results as they developed, by the investigators, the company, and the regulatory authorities involved. The decisions reached are discussed along with the rationale for those decisions and the outcomes.

Aspirin↗

PubMed2001

Effectiveness of self-management training in type 2 diabetes: a systematic review of randomized controlled trials.

OBJECTIVE: To systematically review the effectiveness of self-management training in type 2 diabetes. RESEARCH DESIGN AND METHODS: MEDLINE, Educational Resources Information Center (ERIC), and Nursing and Allied Health databases were searched for English-language articles published between 1980 and 1999. Studies were original articles reporting the results of randomized controlled trials of the effectiveness of self-management training in people with type 2 diabetes. Relevant data on study design, population demographics, interventions, outcomes, methodological quality, and external validity were tabulated. Interventions were categorized based on educational focus (information, lifestyle behaviors, mechanical skills, and coping skills), and outcomes were classified as knowledge, attitudes, and self-care skills; lifestyle behaviors, psychological outcomes, and quality of life; glycemic control; cardiovascular disease risk factors; and economic measures and health service utilization. RESULTS: A total of 72 studies described in 84 articles were identified for this review. Positive effects of self-management training on knowledge, frequency and accuracy of self-monitoring of blood glucose, self-reported dietary habits, and glycemic control were demonstrated in studies with short follow-up (<6 months). Effects of interventions on lipids, physical activity, weight, and blood pressure were variable. With longer follow-up, interventions that used regular reinforcement throughout follow-up were sometimes effective in improving glycemic control. Educational interventions that involved patient collaboration may be more effective than didactic interventions in improving glycemic control, weight, and lipid profiles. No studies demonstrated the effectiveness of self-management training on cardiovascular disease-related events or mortality; no economic analyses included indirect costs; few studies examined health-care utilization. Performance, selection, attrition, and detection bias were common in studies reviewed, and external generalizability was often limited. CONCLUSIONS: Evidence supports the effectiveness of self-management training in type 2 diabetes, particularly in the short term. Further research is needed to assess the effectiveness of self-management interventions on sustained glycemic control, cardiovascular disease risk factors, and ultimately, microvascular and cardiovascular disease and quality of life.

Adaptation, Psychological↗

PubMed2004

The European Competence Network on Mastocytosis (ECNM).

The European Competence Network on Mastocytosis (ECNM) is a Europe-wide, multinational cooperative approach attempting to improve recognition, diagnosis, and therapy of mastocytosis. The network is composed of local centers, physicians, and scientists who have dedicated their work to patients with mastocytosis. However, because of the rarity and complexity of the disease, each single component in the network alone would fail to meet important demands and to reach solid conclusions in this field of applied medicine. The ECNM represents an attempt to overcome this restriction as a cooperative multicenter platform that should serve as an important basis for the development of new therapeutic strategies and diagnostic concepts, and for the standardization of techniques used to determine diagnostic and prognostic parameters. Moreover, using future central databases and registries, a suitable infrastructure for the development of co-operative multicenter clinical trials will be established. In addition, the ECNM is dedicated to provide the best available information about the disease to patients and physicians.

Clinical Competence↗

PubMed2006

[Short-acting insulin analogs--critical assessment of meta-analyses].

Short-acting insulin analogs have for nearly ten years been prescribed for type 1 and 2 diabetes mellitus. There is extensive scientific and practical evidence of their being better than normal insulin. For this reason these insulins have been recommended in the guidelines of most leading specialist societies. In everyday practice they are an important component of the therapeutic portfolio which can produce an improvement in insulin treatment, especially of selective cases. On the other hand, there is growing economic pressure, especially in Germany, affecting their use. However, it must be critically asserted that those meta-analyses on insulin analogs, which have been commissioned by insurance companies or governmental organisations, do not do justice to their advantage. Current meta-analyses of short-acting insulin analogs exclude decisive advantages of insulin analogs from their analyses and compare highly heterogeneous groups. They do not distinguish between differing incidences of hypoglycemia associated with different HbA1c values as well as between conventional and intensive treatment. Furthermore positive data and positive major studies are excluded, while approval studies or trials with completely different aims are cited. Short study duration is also often neglected. As a result, the International Diabetes Federation (IDF) has rejected the Cochrane Review for 2005 for methodological reasons. Also, no recommendations can be derived from the recommendations of of the Institut für Qualitätssicherung und Wirtschaftlichkeit in der Medizin (IQWiG: Institute for Quality Assurance and Cost Effectiveness in Medicine). After critical assessment of meta-analyses the IDF concluded in its guidelines that insulin analogs should generally be used.

Diabetes Mellitus, Type 2↗

PubMed2004

Effect sizes in cumulative meta-analyses of mental health randomized trials evolved over time.

BACKGROUND AND OBJECTIVE: Meta-analyses of randomized trials may incorporate new evidence, and estimated treatment effects changeover time. We evaluated whether the certainty and estimates of efficacy and tolerability of mental health interventions change over time, as more trials appear on the same topics. METHODS: One hundred meta-analyses (1,024 trial entries; 99,303 participants) with an outcome of death, relapse, failure or dropout and with five or more trials published in three or more different years were examined with cumulative meta-analysis and recursive cumulative meta-analysis. RESULTS: Eight meta-analyses reached formal statistical significance (P < .05) at some point, but lost this significance eventually when more trials were published; typically large effect sizes in early trials were dissipated with further evidence. With 500 randomized subjects,95% of the time, subsequent changes in odds ratio might be up to 1.5-fold. For death, relapse, and failure outcomes, a decrease in effect size was somewhat more common than an increase, when more data became available (157 vs. 125, P = .06). This was most clear for comparisons of pharmacotherapies versus placebo (79 vs. 51, P = .009). CONCLUSIONS: Evidence based on a small number of randomized subjects should be interpreted cautiously. Early treatment efficacy of pharmacotherapies is occasionally overestimated.

Data Interpretation, Statistical↗

PubMed2006

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.

Bibliometrics↗

PubMed2007

Examination of the analytic quality of behavioral health randomized clinical trials.

Adoption of evidence-based practice (EBP) policy has implications for clinicians and researchers alike. In fields that have already adopted EBP, evidence-based practice guidelines derive from systematic reviews of research evidence. Ultimately, such guidelines serve as tools used by practitioners. Systematic reviews of treatment efficacy and effectiveness reserve their strongest endorsements for treatments that are supported by high-quality randomized clinical trials (RCTs). It is unknown how well RCTs reported in behavioral science journals fare compared to quality standards set forth in fields that pioneered the evidence-based movement. We compared analytic quality features of all behavioral health RCTs (n = 73) published in three leading behavioral journals and two leading medical journals between January 2000 and July 2003. A behavioral health trial was operationalized as one employing a behavioral treatment modality to prevent or treat an acute or chronic physical disease or condition. Findings revealed areas of weakness in analytic aspects of the behavioral health RCTs reported in both sets of journals. Weaknesses were more pronounced in behavioral journals. The authors offer recommendations for improving the analytic quality of behavioral health RCTs to ensure that evidence about behavioral treatments is highly weighted in systematic reviews.

Behavioral Medicine↗

PubMed2006

Blood pressure management during acute ischaemic stroke.

Control of hypertension is a well-established goal of primary stroke prevention. Management of blood pressure in patients during acute ischaemic stroke, however, is complicated by the need to maintain brain perfusion. Lowering blood pressure in the acute setting may avoid the deleterious effects of high blood pressure but may also lead to cerebral hypoperfusion and worsening of the ischaemic stroke. Little information is available from clinical trials concerning optimal blood pressure management in acute stroke. Current protocols of thrombolytic therapy require strict blood pressure control below certain prescribed limits; however, in most acute stroke patients not treated with thrombolysis, blood pressure reduction is not routinely recommended and guidelines for target blood pressures are difficult to justify. Preliminary studies, in fact, suggest that there may be a role for blood pressure elevation in the treatment of some patients with acute ischaemic stroke.

Adrenergic Antagonists↗

PubMed2002

Rotational atherectomy for the treatment of in-stent restenosis.

Restenosis after coronary stent implantation remains the major limitation of this treatment modality. At present, re-dilatation is considered the therapeutic option of choice for focal lesions, however, long restenotic lesions (>10 mm) do not respond favourably. Despite the emerging concept of intracoronary radiation, encouraging acute procedural results are also reported for different debulking techniques (Excimer laser angioplasty, directional coronary atherectomy, and rotational atherectomy, or rotablation). Rotablation has been studied most extensively with acute and long- term results published in a total of more than 850 patients. Experimental and first clinical data indicate favourable results for the rotablator as compared to balloon angioplasty alone for the treatment of in-stent restenosis. Data from the first 2 randomized clinical trials (ROSTER-, and ARTIST-trial) have now been published with conflicting results: The european multicenter ARTIST-trial including 300 patients could not prove a benefit for the rotablator as compared to re-dilatation in patients with diffuse stent restenosis. On the contrary, the monocenter ROSTER-trial, which has been presented as an abstract until today, suggests a clinical benefit of patients treated by the rotablator if they were studied with intracoronary ultrasound prior to randomization. Currently, rotablation for the treatment of restenosis cannot be considered as the first line treatment modality in patients with in-stent restenosis. As a result of unsatisfying angiographic and clinical long-term results by the use of a variety of treatment modalities in diffuse stent restenosis, prevention of this iatrogenic entity has become mandatory.

Aged↗

PubMed2003

[Chemotherapy with curative intent before (neoadjuvant) or after (adjuvant) surgery for colorectal cancer liver metastases].

The 5-year risk of progression after complete resection of liver metastases is of 50% to 75%. Trials which have evaluated adjuvant systemic chemotherapy using 5FU--folinic acid, sometimes in association with intra-arterial chemotherapy, are not powerful and did not demonstrate a clear survival benefit. It is strongly recommended to participate to clinical trials. An adjuvant chemotherapy with the LV5FU2 regimen during 6 months is a reasonable option if the patient has not been included in a trial (professional agreement). A preoperative chemotherapy is not recommended if liver metastases are considered as right away resectable but it should be discussed if resectability is uncertain and/or in case of pejorative factors (professional agreement). If metastases resection has been facilitated or made possible by pre-operative chemotherapy, post-operative resumption of this chemotherapy should also been discussed (professional agreement).

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2000

Clinical trials results of a unique monoclonal antibody in asthma.

IgE binds to high affinity receptors (Fc epsilon RI) on mast cells, basophils, alveolar macrophages, and antigen-presenting cells. This results in the degranulation of effector cells and the release of mediators, such as histamine, leukotrienes, cytokines, that are causally linked to the pathophysiology of allergic asthma. It made for an attractive target for the development of a unique humanized monoclonal antibody, rhuMAb-E25 (E25). E25 offers a novel strategic approach to allergy treatment, it is expected that using E25 to significantly decrease IgE levels will result in improved control of allergic asthma.

Adult↗

PubMed1995

Prediction and decision making using Bayesian hierarchical models.

This paper uses Bayesian hierarchical models to analyse multi-centre clinical trial data where the outcome variable of interest is continuous, but not normally distributed, and where censoring has occurred. The goal of such an analysis is the same as for any subgroup analysis, to provide survival estimates for specific subgroups as well as for the population and to provide estimates of the degree of heterogeneity between subgroups. An analysis of the Collaborative Study of Long-Term Maintenance Drug Therapy in Recurrent Affective Illness, a multi-centre clinical trial funded by the National Institute for Mental Health's Pharmacologic Research Branch, serves to illustrate the proposed methodology. A feature of this data set is that one treatment group was withdrawn from medication at the time of randomization. The paper contains comparison of models, one that accounts for the drug washout period through the use of a changepoint model as well as a comparison of results across several choices of prior parameter values. In addition, the paper considers sensitivity to model choice and priors in a decision theory context.

Antidepressive Agents, Tricyclic↗

PubMed1998

Evaluation of nursing practice: process and critique.

This article describes the difficulties in conducting clinical trials to evaluate nursing practice models. Suggestions are offered for strengthening the process. A clinical trial of a nursing practice model based on a synthesis of Aristotelian theory with Rogers' science is described. The rationale for decisions regarding the research procedures used in presented. Methodological limitations of the study design and the specifications of the practice model are examined. It is concluded that clear specification of theoretical relationships within a practice model and clear identification of key intervening variables will enable researchers to better connect the treatment with the outcome.

Clinical Nursing Research↗

PubMed1998

Cooperative studies in health services research in the Department of Veterans Affairs.

The Department of Veterans Affairs, through its Cooperative Studies Program, has a long history of conducting large-scale, multihospital biomedical clinical trials. The agency's Health Services Research and Development Service, although newer, has a distinguished record of mainly single-site research into the organization, delivery, and financing of health services. In 1990, a joint program was initiated to conduct multicenter studies in health services research. This article describes the studies developed in the new program and the research design issues encountered in planning them. Identification of the patient population, specification and measurement of the intervention, and description of the control group, as well as attention to the unit of randomization and analysis, outcome variables and choice of effect size, data quality, and ethical considerations are among the important issues related to the design of these studies and future studies in health services.

Delivery of Health Care↗

PubMed1999

Extending Goodman-Kruskal's gamma to the comparison of ordered treatments in multicenter clinical trials.

In a randomized, multicenter clinical trial setting, the treatments may consist of increasing doses of a drug and placebo and the response variable may be ordinal (e.g., physician's global evaluation of treatment effectiveness). Within each center (e.g., hospital), patients are randomly assigned to treatments (rows) such that the row totals are fixed and the rows form a product-multinomial sample of the ordinal response variable. Gamma, a measure of ordinal association in two-way contingency tables, and its asymptotic standard error can be estimated from the data in each center. We use these independent estimates of gamma for testing the hypothesis of homogeneity of gammas, controlling for center effect. If this hypothesis is not rejected, the within-center estimates of gamma can be combined to form a common gamma across the centers.

Biometry↗

PubMed1999

Deriving treatment recommendations from evidence within randomized trials. The role and limitation of meta-analysis.

Meta-analysis is commonly used in reviews of the effectiveness of medical technologies, but this approach has not been used in direct support of guidelines development groups. This paper describes the approach of the North of England Guidelines Development Project in describing the evidence using meta-analyses that were conducted explicitly to address questions on the choice of therapy raised by the guidelines development groups. Particular emphasis is placed on the context within which the contributing trials were conducted and the extent to which systematic differences between trials (heterogeneity) was observed, described, and explained. There is a trade-off between internal and external validity for different metrics when presenting the results of trials. More interpretable metrics, such as risk differences or weighted mean differences, are confounded by study design issues and strong assumptions. More robust measures such as odds ratios or standardized weighted mean differences are difficult to interpret physically. Individual patient data may prove particularly helpful in addressing pivotal questions on the magnitude of effects of interventions, though accessing and reanalyzing these data requires a substantial investment in time and other resources.

Bias↗

PubMed1999

A randomized trial of Evidence-based OutReach (EBOR): rationale and design.

There is increasing interest in evaluating the methods used to implement the findings from medical research. This paper describes the Evidence-based OutReach (EBOR) trial, which is the first large randomized study in the United Kingdom that will evaluate the effectiveness and efficiency of educational outreach visits by trained pharmacists who are delivering messages derived from four evidence-based clinical practice guidelines. General practices form the unit of allocation and analysis. The study design addresses important factors that may influence the effectiveness of the intervention, such as the pharmacist who delivers the messages, the health authority in which practices are located, and the size of a practice.

Family Practice↗

PubMed2003

Should meta-analysts search Embase in addition to Medline?

It is widely accepted that meta-analysts should search multiple databases. The selection of databases is ideally based on the potential contribution of each database to the project or on the potential for bias if a database is excluded, as supported by research evidence. We explore whether searching Embase yields additional trials that influence a meta-analysis. We identified meta-analyses that searched Medline and Embase. A random-effects weighted mean method was used to estimate the intervention effect in articles indexed only in Embase compared with those indexed elsewhere. On average, Embase-unique trials yielded significantly smaller estimates by 29% (ratio of odds ratio [ROR] 0.71, 95% confidence interval [CI] 0.56-0.90) but influenced the pooled estimate by an average of only 6% (ROR 0.94, 95% CI 0.88-0.99). Searching Medline but not Embase risks biasing a meta-analysis by finding studies that show larger estimates, but their prevalence seems low enough that the risk may be slight, provided the rest of the search is comprehensive.

Databases, Bibliographic↗