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Results for “Controlled Clinical Trials as Topic”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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At least 109 records · Page 6Linked to original sources
PubMed1995

Design and analysis of group sequential logrank tests in maximum duration versus information trials.

When monitoring a clinical trial with failure time data using the logrank test and the type I error spending function approach, the information time has to be estimated as a fraction of the maximum number of failures. In maximum duration trials, the denominator of this fraction is a random quantity and has to be estimated; besides, there are two candidates for the denominator, one under the null hypothesis of no treatment difference and the other under the specified alternative hypothesis. Either way, some adjustments are necessary in determining group sequential boundaries in order to maintain type I error at a desired significance level. As a consequence, the type I error spending function will be altered from the one chosen for the design, thus affecting the operating characteristics of the subsequent group sequential logrank tests. In maximum information trials, however, the maximum amount of information is fixed, and thus the estimate of the information time is always unbiased. The net effect is that computation of group sequential boundaries becomes straightforward, with a potential saving in study durations as compared to maximum duration trials. We will illustrate how adjustments are made in maximum duration trials to maintain type I error when the information times are estimated with the information horizons under the null and alternative hypotheses and present numerical explorations to compare robustness of two different estimates of the information times. We then propose a design procedure for maximum information trials and investigate the properties of maximum information trials for different group sequential boundaries. We also compare maximum information trials and maximum duration trials based on an example.

Biometry↗
PubMed1995

Evaluation of clinical trials of agents and procedures to prevent caries and periodontal disease: choosing products and recommending procedures.

The prevention of caries, gingivitis and periodontal diseases has been, and still is, a major objective for the dental profession. A large number of products are available to the general public, either over the counter or on prescription, formulated to prevent these diseases. Formulations are also used by professionals for the prevention and treatment of dental diseases. In recommending or using agents for prevention or therapy it is necessary for the practitioner to appreciate whether proof of efficacy is established. Preventive or therapeutic roles of formulations are frequently confused and there is a need to define the often misleading terminology used to describe products. Guidelines are required to enable the dental professional to understand research data and what constitutes proof of efficacy for preventive and/or therapeutic formulations. The guidelines should describe the research methodologies used today, including study design and analysis, ethics, the format of research papers and the relevance of laboratory data to clinical efficacy.

Anti-Infective Agents, Local↗
PubMed1994

[Molecular biology and cardiac and vascular changes in hypertension: focus on the renin-angiotensin system].

Arterial hypertension is the leading cause of cardiovascular disease in Western countries. In the last few years a widespread application of molecular medicine techniques has led to unprecedent progress in unravelling both the pathogenetic mechanisms of cardiac hypertrophy and accelerated atherosclerosis as well as the genetical markers of susceptibility to cardiovascular disease. Available data demonstrate the presence of all components of the renin-angiotensin system in the heart and arterial wall and suggest that they may play a crucial role in causing both myocardial hypertrophy and atherosclerosis in hypertension. The current research strategies along with the most recent results in this field are reviewed.

Adult↗
PubMed1994

A sample-size-optimal Bayesian procedure for sequential pharmaceutical trials.

Consider a pharmaceutical trial where the consequences of different decisions are expressed on a financial scale. The efficacy of the new drug under consideration has a prior distribution obtained from the underlying biological process, animal experiments, clinical experience, and so forth. Berry and Ho (Biometrics 44, 219-227) show how these components are used to establish an optimal (Bayes) sequential testing procedure, assuming a known constant sample size at each decision point. We show in this article how it is also possible to optimize further, with respect to the sample-size rule. This component of the design, which is missing from most sequential procedures, has the potential to yield considerably larger expected net gains (equivalently, considerably smaller Bayes risks).

Animals↗
PubMed2005

Topical glyceryl trinitrate application in the treatment of chronic supraspinatus tendinopathy: a randomized, double-blinded, placebo-controlled clinical trial.

BACKGROUND: Topical glyceryl trinitrate therapy has previously demonstrated short-term pain reduction in patients with supraspinatus tendinopathy. HYPOTHESIS: Topical glyceryl trinitrate improves outcome measures in patients with supraspinatus tendinopathy. STUDY DESIGN: Randomized controlled clinical trial; Level of evidence, 1. METHODS: Fifty-three patients (57 shoulders) were recruited, and the authors completed a prospective, randomized, double-blinded, placebo-controlled clinical trial of continuous topical glyceryl trinitrate treatment (1.25 mg/24-h glyceryl trinitrate). RESULTS: The glyceryl trinitrate group had significantly reduced shoulder pain with activity, at night, and at rest at week 24 (P = .03); reduced internal rotation impingement at week 24 (P = .02); increased range of motion in abduction and internal rotation at week 24 (P = .04); and increased force at weeks 12 and 24 with supraspinatus muscle testing (P = .001), external rotation (P = .04), internal rotation (P = .01), adduction (P = .04), and subscapularis pushoff (P = .01). Forty-six percent of patients on glyceryl trinitrate patches were asymptomatic with activities of daily living at 6 months compared with 24% of patients with tendon rehabilitation alone (P = .007, chi(2) analysis). Mean effect size for all outcome measures was 0.26. DISCUSSION: Topical glyceryl trinitrate treatment significantly improved pain scores, range of motion, internal rotation impingement, muscular force, and patient outcomes in patients with supraspinatus tendinopathy. Topical glyceryl trinitrate should be included as part of nonsurgical management of chronic tendinopathies.

Administration, Topical↗
PubMed1983

Septic complications after appendicectomy for perforated appendicitis. A controlled clinical trial metronidazole and topical ampicillin.

A prospective, controlled trial of antibiotic therapy was carried out in 90 patients with perforated appendicitis. One randomly selected group received systemic metronidazole, started peroperatively, plus locally instilled ampicillin. The other group, also randomly selected, received only local ampicillin. There was no statistically significant difference in the overall frequency of postoperative septic complications (wound infection or intra-abdominal abscess) between the two groups, but wound infections were significantly fewer in the patients given metronidazole. There was no intergroup difference in hospitalization time. Treatment with systemic metronidazole and local ampicillin is recommended in patients operated on for perforated appendicitis.

Adolescent↗
PubMed1980

Controlled clinical trial of oral and topical diethylcarbamazine in treatment of onchocerciasis.

In a double-blind controlled clinical trial comparing the safety and efficacy of oral diethylcarbamazine citrate (DEC) with topical DEC for the treatment of onchocerciasis twenty men with moderate skin-snip microfilarial counts received daily therapy for 1 week, then weekly therapy for the rest of 6 months. The number of microfilariae per skin snip dropped quickly to 2% of initial levels and remained at low levels in those receiving oral DEC, and to 20% of initial levels in patients treated with DEC lotion. Side-effects in both groups included lymphadenopathy, fever, pruritus, rash, proteinuria, and chorioretinitis; they were commoner with topical DEC.

Administration, Oral↗
PubMed1996

Placebo mania.

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Clinical Trials as Topic↗