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Results for “Randomized Controlled Trials as Topic”

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At least 433 records · Page 24Linked to original sources

PubMed2005

What have we learned about randomized, controlled trials in neonatal sepsis?

OBJECTIVE: To identify strategies to enable randomized, controlled trials in neonatal sepsis to recognize therapies that increase disability-free survival. METHODS: Rapid literature review. RESULTS: Randomized, controlled trials are the gold standard for testing a therapy because they minimize bias. However, randomized, controlled trials must also minimize random error if they are to detect moderate (and realistic) improvements in rates of disability-free survival reliably. This requires surprisingly large samples (i.e., thousands rather than hundreds). Against this perspective, most neonatal trials have been too small to be conclusive, so most neonatal therapies remain incompletely evaluated. As in specialties like cardiology and obstetrics, achieving reliable trials in neonatal sepsis will require international collaboration, simpler data sets, more cost-effective recruitment strategies, less exclusive criteria for selecting collaborators and patients, and an appreciation by clinicians and data-monitoring committees that substantially greater sample sizes are needed to limit the play of chance. Prospective meta-analysis using individual patient data is a promising strategy. It requires researchers to obtain funding from their national agencies to conduct similar trials according to an agreed protocol with prespecified hypotheses, interventions, power calculations, data sets, and measures of outcome. Prospective meta-analysis combines the methodologic advantages of a single "megatrial" with the practical advantages that financial burdens are spread internationally and different national funding cycles can be more flexibly accommodated. CONCLUSIONS: Prospective meta-analysis using individual patient data is a promising strategy for achieving large-scale, randomized evidence in neonatal sepsis.

Critical Illness↗

PubMed1999

How best to fix a broken hip. Fractured Neck of Femur Health Outcomes Project Team.

OBJECTIVES: To develop evidence-based guidelines for the treatment of proximal femoral fractures to optimise functional outcome while minimising length of stay in hospital. DATA SOURCES: Systematic literature search of MEDLINE and CINAHL computer databases, bibliographies, and current contents of key journals for 1966-1995. STUDY SELECTION: English-language randomised controlled trials of all aspects of acute-care hospital treatment of proximal femoral fracture among subjects aged 50 years and over with proximal femoral fractures not due to metastatic disease. DATA EXTRACTION: Two independent reviewers, blinded to authors, institution and study results, followed a standard Cochrane Collaboration protocol and assessed study quality and treatment conclusions. When necessary, a third review was performed to reach consensus. RESULTS: Of the 120 articles published between 1966 and December 1995, 97 met the inclusion criteria. Fifteen clinical interventions were reviewed. Five were supported by National Health and Medical Research Council (NHMRC) level I evidence (prophylactic anticoagulants, prophylactic antibiotics, regional anaesthesia, pressure-relieving mattresses, and internal surgical fixation), two had no supporting randomised controlled trial evidence (time to surgery, time to mobilisation after surgery) and the remainder were classified as having Level II evidence. A review of current practice (1993-94) identified wide variability in these interventions across five acute-care hospitals in the Northern Sydney Area Health Service. CONCLUSIONS: Randomised controlled trial evidence (NHMRC Levels I and II) exists for many, but not all, aspects of hip fracture treatment. There is a need for changes to be made to some aspects of practice in accordance with evidence-based guidelines.

Anesthesia, Conduction↗

PubMed2006

Where next after SPACE and EVA-3S: 'the good, the bad and the ugly!'.

SPACE and EVA-3S are the latest to publish outcomes in recently symptomatic patients who were randomised to carotid endarterectomy (CEA) or angioplasty and stenting (CAS). Contrary to expectations, both found that CAS was not 'as good as' CEA, while EVA-3S found CEA to be statistically superior. Not surprisingly, these trials have aroused considerable controversy and many in the pro-CAS lobby have simply dismissed them as being methodologically flawed and unrepresentative of contemporary CAS practice. However, to simply dismiss SPACE and EVA-3S as maverick trials is unacceptable. Unlike the landmark 'symptomatic' and 'asymptomatic' studies, the history of randomised trials comparing CAS and CEA has been characterised by repeated trial suspension (because of excess risk in the CAs cohort) and a systematic failure to achieve randomisation targets (thereby preventing any prospect of a statistically meaningful outcome) amid a milieu of corporate and individual conflicts of interest. SPACE and EVA-3S have certainly informed the dabate but they have not resolved it. Two trials are actively randomising recently symptomatic patients (ICSS in Europe and CREST in North America). Both require our support so that future guidelines are 'evidence based' rather than 'marker driven'.

Angioplasty↗

PubMed2001

Intergroup collaboration in ovarian cancer: the Gynecologic Cancer Intergroup (GCIG).

Randomized clinical trials are considered the definitive source of evidence for guiding decisions in clinical practise. In patients with ovarian cancer many of the randomized trials from the 1970s and 1980s did not have the statistical power to detect realistic and clinically important differences. Therefore, evolution of so-called "optimal therapy" has been rather slow and some important questions have gone unanswered. In order to overcome this challenge, representatives of different Cooperative Groups started an Ovarian Cancer Trials Intergroup Network in the mid 1990s, as a vehicle to develop future trial collaboration and as a mechanism for communication about strategic directions of phase I/II trials within individual Groups. In 1997 this network became more formalized, going beyond ovarian cancer as a single focus, and the Gynecologic Cancer Intergroup (GCIG) was created. At present GCIG includes representatives of 12 Cooperative Groups and the NCI-US, and functions as a forum for development of global trial collaborations, which hopefully will answer important questions in a more timely fashion and make them more rapidly available for the oncologic community.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

Evidence-based practice: extending the search to find material for the systematic review.

BACKGROUND: Cochrane-style systematic reviews increasingly require the participation of librarians. Guidelines on the appropriate search strategy to use for systematic reviews have been proposed. However, research evidence supporting these recommendations is limited. OBJECTIVE: This study investigates the effectiveness of various systematic search methods used to uncover randomized controlled trials (RCTs) for systematic reviews. Effectiveness is defined as the proportion of relevant material uncovered for the systematic review using extended systematic review search methods. The following extended systematic search methods are evaluated: searching subject-specific or specialized databases (including trial registries), hand searching, scanning reference lists, and communicating personally. METHODS: Two systematic review projects were prospectively monitored regarding the method used to identify items as well as the type of items retrieved. The proportion of RCTs identified by each systematic search method was calculated. RESULTS: The extended systematic search methods uncovered 29.2% of all items retrieved for the systematic reviews. The search of specialized databases was the most effective method, followed by scanning of reference lists, communicating personally, and hand searching. Although the number of items identified through hand searching was small, these unique items would otherwise have been missed. CONCLUSIONS: Extended systematic search methods are effective tools for uncovering material for the systematic review. The quality of the items uncovered has yet to be assessed and will be key in evaluating the value of the systematic search methods.

Humans↗

PubMed2004

Clinical trials and lipid guidelines for type II diabetes.

The management of dyslipidemia in adults with diabetes is receiving more attention. However, there is a paucity of large, prospective, randomized outcome trials designed for diabetic patients. Diabetic dyslipidemia is characterized by an increase in triglyceride levels, low high-density lipoprotein (HDL) cholesterol concentrations, and small, dense low-density lipoprotein (LDL) particles. The treatment goals include an LDL cholesterol less than 100 mg/dL, triglyceride level less than 150 mg/dL, and an HDL greater than 40 mg/dL for men and more than 50 mg/dL for women. In the Diabetic Atherosclerosis Intervention Study, fenofibrate resulted in a 42% less increase in the percent stenosis, as assessed by quantitative coronary arteriography. The Heart Protection Study documented the unambiguous benefit of simvastatin in reducing all-cause mortality among 5963 diabetic patients. The Lescol Intervention Prevention Study observed a reduction in major adverse cardiac events in diabetics undergoing percutaneous intervention who received fluvastatin. The Veterans Affairs HDL Cholesterol Intervention Trial reported a reduction in major coronary events among 627 diabetic patients with low HDL cholesterol who sustained a myocardial infarction. The Fenofibrate Intervention and Event Lowering in Diabetics (FIELD) Trial (n = 9795), the Action to Control Cardiovascular Risk in Diabetes (ACCORD, n = 10,000), the Atorvastatin Study for Prevention of Coronary Heart Disease Endpoints in Non Insulin Dependent Diabetes Mellitus (ASPEN, n = 2421), and the Collaborative Atorvastatin Diabetes Study (CARDS, n = 2140) will provide the prospective outcome data that are needed for the management of patients. Combination drug therapy will be necessary to achieve treatment goals. Careful monitoring will be required to avoid myositis and hepatotoxicity.

Cardiovascular Diseases↗

PubMed2006

Challenges and opportunities for pharmacoepidemiology in drug-therapy decision making.

Pharmacoepidemiology is a relatively new and evolving science that attempts to quantify mainly adverse drug events and patterns of drug use in a large population. The strength of pharmacoepidemiology over randomized trials is the ability to quantify rare adverse events that may occur over long periods. Recently, discordance in the results of pharmacoepidemiologic studies has made it difficult for clinicians and policy makers to make informed drug-therapy decisions. This commentary addresses the strength of pharmacoepidemiology and the advances in the methodology of pharmacoepidemiologic studies over the years. We also discuss the potential problem of discordant results and urge pharmacoepidemiologists to develop good practice guidelines for the conduct of pharmacoepidemiologic studies.

Adverse Drug Reaction Reporting Systems↗

PubMed2006

Designing an acupuncture study: II. The nationwide, randomized, controlled German acupuncture trials on low-back pain and gonarthrosis.

BACKGROUND: In the nationwide German Acupuncture Trials (GERAC), verum acupuncture, mirroring the Traditional Chinese Medicine (TCM) acupuncture style, was tested against sham acupuncture and guideline standard therapy for the entities classified in the West as chronic low back pain (LBP) and gonarthrosis (GON). OBJECTIVE: The objective was to develop broadly consensual acupuncture and control protocols for the treatment of LBP and GON in the GERAC trials. METHODOLOGY: Extensive literature study and consultation with acupuncture experts were consulted. Personal interviews, both free and structured, e-mail discussions, and phone conferences were used as well. RESULTS: Broadly consensual acupuncture protocols for LBP and GON for verum and invasive sham acupuncture were developed. They included semistandardized point combinations with clearly described point selection rules based on TCM acupuncture diagnosis. A procedure was developed to help ensure homogenous treatment quality in a large multicenter trial. CONCLUSIONS: With 1162 randomized patients for LBP and 1039 patients for GON, the GERAC study design allowed acupuncture to be tested in a naturalistic environment. The rigorous study design and large number of physician investigators guaranteed a high external validity for the results. The results will help determine the significance of Chinese acupuncture in the context of Western medicine for the treatment of LBP and GON.

Acupuncture Points↗

PubMed2004

Diabetes patient education: a meta-analysis and meta-regression.

Diabetes education has largely been accepted in diabetes care. The effect of diabetes education on glycemic control and the components of education responsible for such an effect are uncertain. We performed a meta-analysis of randomized controlled trials of diabetes patient education published between 1990 and December 2000 to quantitatively assess and characterize the effect of patient education on glycated hemoglobin (HbA(1c)). Additionally, we used meta-regression to analyze which variables within an education intervention that best explained variance in glycemic control. Twenty-eight educational interventions (n=2439) were included in the analysis. The net glycemic change was 0.320% lower in the intervention group than in the control group. Meta-regression revealed that interventions which included a face-to-face delivery, cognitive reframing teaching method, and exercise content were more likely to improve glycemic control. Those three areas collectively explained 44% of the variance in glycemic control. Current patient education interventions modestly improve glycemic control in adults with diabetes. We highlight three potential components of educational interventions that may predict an increased likelihood of success in ameliorating glycemic control.

Adult↗

PubMed1996

Randomized controlled trials and systematic reviews: a foundation for evidence-based perinatal medicine.

The objective of this paper is to introduce the reader to clinical research methodologies and to illustrate how randomized controlled trials (RCTs) and systematic reviews provide a solid foundation for evidence-based perinatal practice. Relevant references were critically appraised for validity and usefulness. Random allocation is of utmost importance to avoid bias. There are thousands of reported perinatal RCTs. Systematic review techniques allow clinicians to assess the effectiveness of perinatal interventions. The application of the results of systematic reviews to perinatal practice is increasing. RCTs and systematic reviews provide the most valid results on which to build an evidence-based perinatal practice. A major challenge for perinatal researchers is the development of innovative means of communication. This assures that the evidence for an effective intervention is timely implemented. Consumers of care should be encouraged to actively participate in the design, execution and dissemination of perinatal research.

Bias↗

PubMed2007

Evidence-based sample size calculations based upon updated meta-analysis.

Meta-analyses of randomized controlled trials (RCTs) provide the highest level of evidence regarding the effectiveness of interventions and as such underpin much of evidence-based medicine. Despite this, meta-analyses are usually produced as observational by-products of the existing literature, with no formal consideration of future meta-analyses when individual trials are being designed. Basing the sample size of a new trial on the results of an updated meta-analysis which will include it, may sometimes make more sense than powering the trial in isolation. A framework for sample size calculation for a future RCT based on the results of a meta-analysis of the existing evidence is presented. Both fixed and random effect approaches are explored through an example. Bayesian Markov Chain Monte Carlo simulation modelling is used for the random effects model since it has computational advantages over the classical approach. Several criteria on which to base inference and hence power are considered. The prior expectation of the power is averaged over the prior distribution for the unknown true treatment effect. An extension to the framework allowing for consideration of the design for a series of new trials is also presented. Results suggest that power can be highly dependent on the statistical model used to meta-analyse the data and even very large studies may have little impact on a meta-analysis when there is considerable between study heterogeneity. This raises issues regarding the appropriateness of the use of random effect models when designing and drawing inferences across a series of studies.

Anti-Bacterial Agents↗

PubMed1998

A randomized, placebo-controlled trial of topical cyclosporin A in steroid-dependent atopic keratoconjunctivitis.

OBJECTIVE: This study aimed to investigate the therapeutic effect of topical cyclosporin A (CsA) 2% in maize oil as a steroid-sparing agent in steroid-dependent atopic keratoconjunctivitis. DESIGN: Prospective, randomized, double-masked, placebo-controlled trial. PARTICIPANTS: Twenty-one patients with steroid-dependent atopic keratoconjunctivitis were studied. INTERVENTION: Patients used either topical CsA or vehicle four times daily for 3 months in addition to their usual therapy, and the clinical response was used to taper or stop topical steroids when possible. MAIN OUTCOME MEASURES: Steroid drop usage per week, ability to cease steroid use, scores for symptoms and clinical signs, drop side effects, and overall subjective rating of trial drop by patients and clinician were measured. RESULTS: Cyclosporin A had a greater steroid-sparing effect than did placebo. Nine of 12 CsA patients ceased steroids compared to 1 of 9 placebo patients (P = 0.01), the final steroid use was lower in the CsA group (2.6 +/- 1.4 vs. 27.7 +/- 17.7, P = 0.005), and the mean reduction in steroid use was greater for CsA (85.5 +/- 14.7 vs. 13.9 +/- 16.0, P = 0.005). Clinical signs and symptom scores were reduced to a greater level for CsA. Serious side effects were lid skin maceration in one patient using CsA and an allergic reaction in one placebo patient. Marked blurring of vision after drop instillation was common in both groups, but intense stinging was more common in CsA patients (9/12 vs. 1/9, P = 0.01), limiting frequency of drop use. The clinician rated the trial drops as good or excellent more frequently for CsA (11/12 vs. 0/9, P < 0.0001). CONCLUSIONS: Topical CsA is an effective and safe steroid-sparing agent in atopic keratoconjunctivitis and, despite difficulties in patient tolerance, also improves symptoms and signs.

Administration, Topical↗

PubMedDate not supplied

Efficient means of studying ancillary questions in clinical trials.

Ancillary questions in clinical trials can often be answered by studying subcohorts of the participants. If the question compares responses between treatment groups, a subcohort that preserves the randomization can be used. However, if the question can be answered by analysis within a treatment group or by combining treatment groups, efficient methods developed for observational studies can be used. These methods include case-control and case-cohort methods.

Case-Control Studies↗

PubMedDate not supplied

Diets do not fail: the success of medical nutrition therapy in patients with diabetes.

OBJECTIVE: To emphasize the importance of medical nutrition therapy in the overall management of diabetes. METHODS: Published reports of the effectiveness of nutrition intervention in glycemic control are reviewed, and useful strategies for implementation of lifestyle changes in patients with diabetes are discussed. RESULTS: In randomized controlled trials of nutrition therapy in patients with diabetes, reduction in hemoglobin A1c levels has been demonstrated. The focus of medical nutrition intervention in patients with diabetes should be strategies that will address the metabolic abnormalities of glucose, lipids, and blood pressure associated with this disease. Early referral for lifestyle changes and advice will yield the most benefit in prevention of development of type 2 diabetes or minimization of progression of the disease if the diagnosis has already been made. Patients should be educated about the progressive nature of type 2 diabetes and the importance of glycemic control, with appropriate food choices and physical activity in conjunction with their antidiabetes medication. CONCLUSION: The health-care team can provide practical and useful information to patients with diabetes that will improve management of their disease and enhance their well-being.

Blood Glucose↗

PubMed2003

Generalizability of guidelines and physicians' adherence. Case study on the Sixth Joint National Commitee's guidelines on hypertension.

BACKGROUND: Clinical practice guidelines (CPG) are thought to be an effective tool in improving efficiency and outcomes of clinical practice. Physicians' adherence to guidelines is reported to be poor. We evaluated the relationship between generalizability of guidelines on hypertension and physicians' adherence to guidelines' recommendations for pharmacological treatment. METHODS: We used the Sixth Joint National Committee's (JNC VI) guidelines on hypertension to evaluate our hypothesis. We evaluated the evidence from controlled clinical trials on which the JNC VI bases its recommendation, and compared the population enrolled in those trials with the American hypertensive population. Data on this population came from the National Health and Nutritional Examination Survey III. RESULTS: Twenty-three percent of the NHANES population had a diagnosis of hypertension, 11% had hypertension requiring drug treatment according to the JNC VI. Only half of the population requiring treatment would have been enrolled in at least two trials. Rate of adherence to CPG was 69%. We found a weak association between generalizability and physicians' adherence to guidelines. Baseline risk was the major determinant of the decision to treat. CONCLUSION: JNC VI guidelines may not be generalizable to their target population. We found a relatively poor adherence rate to these guidelines. Failing of completely taking into account the clinical characteristics of the patients may be partly responsible for this lack of adherence.

Adrenergic beta-Antagonists↗

PubMed2006

Basic concepts in meta-analysis: A primer for clinicians.

With the expanding volume of medical literature, meta-analysis, a form of systematic review, has become indispensable for clinicians for evidence-based decision making. While the number of meta-analyses has substantially increased during recent years, there are still controversial issues regarding their methodology, interpretation and clinical application. In this review, the basic concepts of meta-analysis have been discussed from a clinician's perspective in order to facilitate its understanding, appraising and applicability in clinical practice. Although randomised controlled trials are the usual source for meta-analysis, observational studies are also being increasingly considered for meta-analysis. Like every other research design, meta-analysis starts with formulating a question, followed by searching for related data, based on predefined criteria and strategies. Inclusion of studies must be carried out with careful consideration of their quality and assessment of homogeneity using graphical means as well as statistical tools such as Q statistics, I(2) statistics and meta-regression. The pooled effect size is commonly calculated using either a 'fixed effect model' or 'random effect model'. Publication bias and other source of bias should be investigated and the impact of potential confounders should be eliminated as required. Given the above-mentioned considerations, meta-analysis can provide a more precise estimate of an effect size to be used in clinical decision making.

Bias↗

PubMed2000

Establishing guidelines for pharmacotherapy trials in bulimia nervosa and anorexia nervosa.

OBJECTIVE: This paper addresses the lack of a standard protocol for pharmacotherapy trials for patients with bulimia nervosa (BN) and anorexia nervosa (AN). METHOD: Twenty-two surveys were sent to established researchers in the field of eating disorders to elicit their opinions regarding medication trials, including baseline laboratory tests, the optimal length/frequency of medication management sessions, and the information that should or should not be included in these sessions. RESULTS: Sixteen of 22 researchers completed and returned the survey. Their answers are the basis of the data presented. DISCUSSION: We propose a battery of screening laboratory tests for both conditions. We suggest 30-45-min initial medication management sessions in both AN and BN trials with 15-min follow-ups to be held weekly for AN subjects, and weekly for 2 weeks, then biweekly for 2 weeks, then monthly, for BN subjects. We also recommend that published trials should include explicit details of medication management.

Anorexia Nervosa↗

PubMed2000

Statistics in medical journals: some recent trends.

I review some areas of medical statistics that have gained prominence over the last 5-10 years: meta-analysis, evidence-based medicine, and cluster randomized trials. I then consider several issues relating to data analysis and interpretation, many relating to the use and misuse of hypothesis testing, drawing on recent reviews of the use of statistics in medical journals. I also consider developments in the reporting of research in medical journals.

Data Interpretation, Statistical↗