Advantages and disadvantages of evidence from clinical trials

2001 ◽  
Vol 6 (2) ◽  
pp. 136-139 ◽  
Author(s):  
Alan Earl‐Slater
Keyword(s):  
Clinical Trials ◽  
Advantages And Disadvantages

scholarly journals Prasugrel versus ticagrelor in acute coronary syndromes

2021 ◽  
pp. 1-7
Author(s):  
Luiz Tanajura ◽  
José Costa Júnior ◽  
Áurea Chaves ◽  
Marinella Centemero ◽  
Fausto Feres
Keyword(s):  
Clinical Trials ◽  
Acute Coronary Syndromes ◽  
Therapeutic Option ◽  
High Morbidity ◽  
Cardiac Events ◽  
Invasive Treatment ◽  
New Agents ◽  
Advantages And Disadvantages ◽  
Coronary Syndromes ◽  
New Generation

Acute coronary syndromes are common situations in medical practice, with high morbidity and mortality. Consequent to its relevance, its clinical management has always been subject of discussion and controversy. Since the past decade, the dual antiplatelet regimen has been the main therapeutic option used in its passivation, whereas percutaneous interventions have become the most common therapeutic option. Clopidogrel, the drug initially used in combination with aspirin, is effective and safe; however, it has disadvantages that led to the development of a new generation of more efficient antiplatelet drugs, such as prasugrel and ticagrelor. In large comparative clinical trials, these two drugs proved superior to clopidogrel in reducing major combined cardiac events. Hence the main guidelines currently support the two new agents, which are considered first-line drugs. Due to the clear differences between the protocols of clinical trials corroborating their inclusion in clinical practice, it is not possible to make direct comparison without the risk of generating hasty impressions. More recently, a large prospective, randomized clinical trial provided an appropriate head-to-head comparison between prasugrel and ticagrelor in cases of acute coronary disease, in a population submitted to invasive treatment. The study demonstrated a significant advantage of prasugrel. In this review, we discuss the primary details of these more contemporary drugs and the most relevant clinical trials related to them, identifying the advantages and disadvantages of each agent. At the end, we state our view on their current prescription.

scholarly journals Unilateral and Bilateral Laryngeal Pacing for Bilateral Vocal Fold Paralysis

2020 ◽  
Vol 8 (4) ◽  
pp. 395-401
Author(s):  
Maria E. Powell ◽  
David L. Zealear ◽  
Yike Li ◽  
C. Gaelyn Garrett ◽  
Kate Von Wahlde ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Minimally Invasive ◽  
Vocal Fold ◽  
Vocal Fold Paralysis ◽  
Strenuous Exercise ◽  
Advantages And Disadvantages ◽  
Bilateral Vocal Fold Paralysis ◽  
Posterior Cricoarytenoid Muscle ◽  
Posterior Cricoarytenoid ◽  
Better Than

Abstract Purpose of Review Present the state-of-the-art overview of laryngeal pacing for treatment of bilateral vocal fold paralysis. A minimally invasive unilateral pacing system and a fully implantable bilateral pacing system are currently in clinical trials. The relative advantages and disadvantages of each are discussed. Recent Findings Research in functional electrical stimulation for the reanimation of the posterior cricoarytenoid muscle has successfully translated from animal models to human clinical trials for unilateral pacing and bilateral pacing. Current findings suggest unilateral pacing in humans significantly improves ventilation but only marginally better than cordotomy. Bilateral pacing in canines increases glottal opening greater than 2-fold over unilateral pacing and restores exercise tolerance to normal. Summary Unilateral pacing can be considered a breathing assist device and may not be appropriate for active individuals. Bilateral pacing may be preferable for patients who wish to engage in strenuous exercise. Minimally invasive systems may be ideal for patients who prefer less invasive implantation and are not concerned with cosmesis. Fully implantable pacing systems offer greater electrode redundancy and stability, resulting in a system that is robust against electrode migration or damage.

An overview of study designs

2020 ◽  
Vol 81 (5) ◽  
pp. 1-6
Author(s):  
Julian Aquilina ◽  
Joana B Neves ◽  
Maxine GB Tran
Keyword(s):  
Clinical Trials ◽  
Study Design ◽  
Evidence Based Medicine ◽  
Evidence Based ◽  
Advantages And Disadvantages ◽  
Valid Evidence ◽  
Study Designs ◽  
Based Medicine

The numbers of clinical trials have increased exponentially over the last decade, amplifying the pressure to select an appropriate study design to obtain reliable and valid evidence. The ability to find, critically appraise and use evidence to develop new interventions is fundamental to evidence-based medicine. Different study designs have their own advantages and disadvantages, and provide different evidentiary value. This article provides an overview of clinical trials, illustrating that, ultimately, the study design chosen needs to meet experimental and funding limitations, while minimising error.

scholarly journals Shock – Classification and Pathophysiological Principles of Therapeutics

2019 ◽  
Vol 15 (2) ◽  
pp. 102-113 ◽  
Author(s):  
Olga N. Kislitsina ◽  
Jonathan D. Rich ◽  
Jane E. Wilcox ◽  
Duc T. Pham ◽  
Andrei Churyla ◽  
...  
Keyword(s):  
Septic Shock ◽  
Clinical Trials ◽  
Hypovolemic Shock ◽  
Experimental Studies ◽  
Shock Therapy ◽  
Advantages And Disadvantages ◽  
Clinical Presentations ◽  
Endogenous Catecholamines ◽  
Omecamtiv Mecarbil ◽  
Vasopressor Agents

The management of patients with shock is extremely challenging because of the myriad of possible clinical presentations in cardiogenic shock, septic shock and hypovolemic shock and the limitations of contemporary therapeutic options. The treatment of shock includes the administration of endogenous catecholamines (epinephrine, norepinephrine, and dopamine) as well as various vasopressor agents that have shown efficacy in the treatment of the various types of shock. In addition to the endogenous catecholamines, dobutamine, isoproterenol, phenylephrine, and milrinone have served as the mainstays of shock therapy for several decades. Recently, experimental studies have suggested that newer agents such as vasopressin, selepressin, calcium-sensitizing agents like levosimendan, cardiac-specific myosin activators like omecamtiv mecarbil (OM), istaroxime, and natriuretic peptides like nesiritide can enhance shock therapy, especially when shock presents a more complex clinical picture than normal. However, their ability to improve clinical outcomes remains to be proven. It is the purpose of this review to describe the mechanism of action, dosage requirements, advantages and disadvantages, and specific indications and contraindications for the use of each of these catecholamines and vasopressors, as well as to elucidate the most important clinical trials that serve as the basis of contemporary shock therapy.

Relative efficiencies of alternative preference-based designs for randomised trials

2020 ◽  
Vol 29 (12) ◽  
pp. 3783-3803
Author(s):  
SD Walter ◽  
M Bian
Keyword(s):  
Clinical Trials ◽  
Patient Preferences ◽  
Relative Efficiency ◽  
Randomised Trials ◽  
Advantages And Disadvantages ◽  
Relative Preference ◽  
Parallel Group ◽  
Alternative Designs ◽  
Trial Participants ◽  
Do So

Recent work has shown that outcomes in clinical trials can be affected by which treatment the trial participants would select if they were allowed to do so, and if they do or do not actually receive that treatment. These influences are known as selection and preference effects, respectively. Unfortunately, they cannot be evaluated in conventional, parallel group trials because patient preferences remain unknown. However, several alternative designs have been proposed, to measure and take account of patient preferences. In this paper, we discuss three preference-based designs (the two-stage, fully randomised, and partially randomised designs). In conventional trials, only the treatment effect is estimable, while the preference-based designs have the potential to estimate some or all of the selection and preference effects. The relative efficiency of these designs is affected by several factors, including the proportion of participants who are undecided about treatments, or who are unable or unwilling to state a preference; the relative preference rate between the treatments being compared, among patients who do have a preference; and the ratio of patients randomised to each treatment. We also discuss the advantages and disadvantages of these designs under different scenarios.

Comparison of survival distributions in clinical trials: A practical guidance

2020 ◽  
Vol 17 (5) ◽  
pp. 507-521
Author(s):  
Xiaotian Chen ◽  
Xin Wang ◽  
Kun Chen ◽  
Yeya Zheng ◽  
Richard J Chappell ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Proportional Hazards ◽  
Statistical Tests ◽  
Type I ◽  
Analysis Method ◽  
Primary Analysis ◽  
Logrank Test ◽  
Nonproportional Hazards ◽  
Advantages And Disadvantages ◽  
Proportional Hazards Assumption

Background In randomized clinical trials with censored time-to-event outcomes, the logrank test is known to have substantial statistical power under the proportional hazards assumption and is widely adopted as a tool to compare two survival distributions. However, the proportional hazards assumption is impossible to validate in practice until the data are unblinded. However, the statistical analysis plan of a randomized clinical trial and in particular its primary analysis method must be pre-specified before any unblinded information may be reviewed. Purpose The purpose of this article is to guide applied biostatisticians in the prespecification of a desired primary analysis method when a treatment effect with nonproportional hazards is anticipated. While articles proposing alternate statistical tests are aplenty, to the best of our knowledge, there is no article available that attempts to simplify the choice and prespecification of a primary statistical test under specific expected patterns on nonproportional hazards. We provide such guidance by reviewing various tests proposed as more powerful alternatives to the standard logrank test under nonproportional hazards and simultaneously comparing their performance under a wide variety of nonproportional hazards scenarios to elucidate their advantages and disadvantages. Method In order to select the most preferable test for detecting specific differences between survival distributions of interest while controlling false positive rates, we review and assess the performance of weighted and adaptively weighted logrank tests, weighted and adaptively weighted Kaplan–Meier tests and versatile tests under various patterns of nonproportional hazards treatment effects through simulation. Conclusion We validate some of the claimed properties of the proposed extensions and identify tests that may be more preferable under specific expected pattern of nonproportional hazards when such knowledge is available. We show that versatile tests, while achieving robustness to departures from proportional hazards, may lose interpretation of directionality (superiority or inferiority) and can only be seen to test departures from equality. Detailed summary and discussion of the performance of each test in terms of type I error rate and power are provided to formulate specific guidance about their applicability and use.

Trends in case-control allocation in phase III randomized cancer clinical trials.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e14582-e14582
Author(s):  
Shruti Gupta ◽  
Swathi Gopishetty ◽  
Srishti Malhotra ◽  
Vamsi Kota ◽  
Anand P. Jillella ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Clinical Trial Design ◽  
Phase Iii ◽  
Cancer Clinical Trials ◽  
Unequal Distribution ◽  
Equal Distribution ◽  
Advantages And Disadvantages ◽  
Significant Difference ◽  
And Control ◽  
Unequal Allocation

e14582 Background: Patients enrollment in cancer clinical trials has traditionally been limited to an equal distribution between cases and controls. Some clinical trials have an unequal distribution between the case and control arm. Although such unequal allocation is uncommon it has certain advantages and disadvantages to it. The trend and proportion of cancer clinical trials that have an unequal allocation has not been studied. Methods: Data about cancer clinical trials was extracted from clinical trials.gov. The query included phase 3 trials which included adults and were conducted between 2010 to 2017. Only clinical trials that were either completed or active – but not recruiting were included. T test was used to determine statistical difference between different subgroups. Results: 601 clinical trials were identified of which 356 trials with two arms and 47 trials with 3+ arms were identified. Amongst the eligible 298 trials with two arms, there were 216 trials with equal allocation (1:1) and 82 trials with unequal allocation. Amongst the eligible 29 trials with 3+ arms; there were 21 trials with equal allocation (1:1:1) and 8 trials with unequal allocation. There was no significant difference in the proportion of trials with unequal allocation over the time period from 2010 to 2017. The categories of cancer which had the highest number of two arm clinical trials with unequal allotment were: genitourinary, breast and hematological malignancies (Table). Conclusions: Cancer clinical trials with unequal allocation between case and control arms have been common in the past decade. This may represent a new trend in clinical trial design to help enhance closer monitoring of adverse events despite higher costs attached to this method.[Table: see text]

scholarly journals The challenges of control groups, placebos and blinding in clinical trials of dietary interventions

2017 ◽  
Vol 76 (3) ◽  
pp. 203-212 ◽  
Author(s):  
Heidi M. Staudacher ◽  
Peter M. Irving ◽  
Miranda C. E. Lomer ◽  
Kevin Whelan
Keyword(s):  
Clinical Trials ◽  
Dietary Intervention ◽  
Research Review ◽  
Dietary Advice ◽  
Dietary Interventions ◽  
Advantages And Disadvantages ◽  
Sham Intervention ◽  
Potential Risks ◽  
Intervention Trials

High-quality placebo-controlled evidence for food, nutrient or dietary advice interventions is vital for verifying the role of diet in optimising health or for the management of disease. This could be argued to be especially important where the benefits of dietary intervention are coupled with potential risks such as compromising nutrient intake, particularly in the case of exclusion diets. The objective of the present paper is to explore the challenges associated with clinical trials in dietary research, review the types of controls used and present the advantages and disadvantages of each, including issues regarding placebos and blinding. Placebo-controlled trials in nutrient interventions are relatively straightforward, as in general placebos can be easily produced. However, the challenges associated with conducting placebo-controlled food interventions and dietary advice interventions are protean, and this has led to a paucity of placebo-controlled food and dietary advice trials compared with drug trials. This review appraises the types of controls used in dietary intervention trials and provides recommendations and nine essential criteria for the design and development of sham diets for use in studies evaluating the effect of dietary advice, along with practical guidance regarding their evaluation. The rationale for these criteria predominantly relate to avoiding altering the outcome of interest in those delivered the sham intervention in these types of studies, while not compromising blinding.

scholarly journals The race for a coronavirus vaccine

Bionatura ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 1290-1292
Author(s):  
Gerardo Ferbeyre ◽  
Nelson Santiago Vispo
Keyword(s):  
Clinical Trials ◽  
Viral Vectors ◽  
Phase 1 ◽  
Phase 3 ◽  
Antiviral Immune Response ◽  
Degree Of Protection ◽  
Advantages And Disadvantages ◽  
Phases Of Development ◽  
Vaccination Campaigns ◽  
Short Time

The international race to find a preventive vaccine and effective treatments against COVID 19 has been influenced by two fundamental factors. Firstly, by the molecular characterization of the causative virus and the pathology it produces, and secondly, by access to this information, mostly free of charge by the international scientific community causing a synergy to obtain results in such a short time. Several vaccines preparations against Covid19 have entered Phase 3 clinical trials. Although it is uncertain the degree of protection that they will achieve, preliminary data from Phase 1 and 2 trials and studies in animals indicate that they trigger an antiviral immune response without serious side effects. The current formulations include viral vectors, RNA vaccines, inactivated viruses, and recombinant proteins particles. They all have advantages and disadvantages, but only the results of Phase 3 clinical trials will ultimately decide the best candidates for vaccination campaigns. The tremendous impact of the SARS-CoV-2 in our society has triggered an unprecedented effort to find a vaccine to control the pandemic. Billions of dollars have already been invested in multiple vaccination schemes. According to the WHO, more than 170 vaccines were in different phases of development in August 2020. Here is a summary of the advantages and disadvantages of the front runner strategies categorized according to their delivery method.

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