Randomized clinical trials in the presence of diagnostic uncertainty: Implications for measures of efficacy and sample size

1996 ◽  
Vol 17 (3) ◽  
pp. 191-200
Author(s):  
Jesse A. Berlin ◽  
Roberta B. Ness
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Randomized Clinical Trials ◽  
Diagnostic Uncertainty

Statistical power of negative randomized clinical trials (RCTs) presented at the American Society of Clinical Oncology (ASCO) Annual Meetings

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 6516-6516
Author(s):  
P. Bedard ◽  
M. K. Krzyzanowska ◽  
M. Pintilie ◽  
I. F. Tannock
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Annual Meeting ◽  
Primary Endpoint ◽  
Effect Size ◽  
Statistical Power ◽  
Randomized Clinical Trials ◽  
Medium Effect ◽  
Post Hoc ◽  
Adequate Sample Size

6516 Background: Underpowered randomized clinical trials (RCTs) may expose participants to risks and burdens of research without scientific merit. We investigated the prevalence of underpowered RCTs presented at ASCO annual meetings. Methods: We surveyed all two-arm parallel phase III RCTs presented at the ASCO annual meeting from 1995–2003 where differences for the primary endpoint were non-statistically significant. Post hoc calculations were performed using a power of 80% and a=0.05 (two-sided) to determine the sample size required to detect a small, medium, and large effect size between the two groups. For studies reporting a proportion or time to event as a primary endpoint, effect size was expressed as an odds ratio (OR) or hazard ratio (HR) respectively, with a small effect size defined as OR/HR=1.3, medium effect size OR/HR=1.5, and large effect OR/HR=2.0. Logistic regression was used to identify factors associated with lack of statistical power. Results: Of 423 negative RCTs for which post hoc sample size calculations could be performed, 45 (10.6%), 138 (32.6%), and 333 (78.7%) had adequate sample size to detect small, medium, and large effect sizes respectively. Only 35 negative RCTs (7.1%) reported a reason for inadequate sample size. In a multivariable model, studies presented at plenary or oral sessions (p<0.0001) and multicenter studies supported by a co-operative group were more likely to have adequate sample size (p<0.0001). Conclusion: Two-thirds of negative RCTs presented at the ASCO annual meeting do not have an adequate sample to detect a medium-sized treatment effect. Most underpowered negative RCTs do not report a sample size calculation or reasons for inadequate patient accrual. No significant financial relationships to disclose.

Effect of Predictive Performance of a Biomarker for the Sample Size of Targeted Designs for Randomized Clinical Trials

2011 ◽  
Vol 3 (4) ◽  
pp. 536-548 ◽  
Author(s):  
Xiwu Lin ◽  
Daniel C. Parks ◽  
Joel Greshock ◽  
Richard Wooster ◽  
Kwan R. Lee
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Randomized Clinical Trials ◽  
Predictive Performance

scholarly journals Broccoli and Helicobacter Pylori: A Systematic Review

2020 ◽  
Vol 10 (1) ◽  
pp. 2-11
Author(s):  
Fatemeh Azizi-Soleiman ◽  
◽  
Maryam Zamanian ◽  
Keyword(s):  
Systematic Review ◽  
Clinical Trials ◽  
Helicobacter Pylori ◽  
Sample Size ◽  
Randomized Clinical Trials ◽  
Small Sample Size ◽  
Small Sample ◽  
Animal Testing ◽  
H Pylori ◽  
Positive Effect

Objective: Pharmacological treatment of Helicobacter pylori (H. pylori) infection is based on the use of at least two antibiotics with a double dose of proton pump inhibitor which results in antibiotic resistance. Anti-helicobacterial activity of sulforaphane-rich broccoli has been evaluated in laboratory studies. This study aimed to systematically review the conducted randomized clinical trials that have examined the effect of broccoli on H. pylori in humans. Methods: This study is a systematic review of randomized clinical trials on the effect of broccoli on H. pylori. The search was conducted in PubMed, OVID, Web of Science, and Scopus databases using the keywords: Helicobacter pylori, broccoli sprouts, H. pylori, randomized clinical trials, and Brassica, without any time limits for studies conducted until 2019. After excluding duplicates, the titles and abstracts of remained articles were evaluated by two researchers and then the related ones were extracted. Next, their full-texts were examined to select the final articles for review. We included clinical trials and excluded those were in the laboratory or animal testing phases or their full-texts were unavailable. Results: Three studies that had met the inclusion criteria were considered for the review. Overall, neither in the articles that reviewed in the present study nor in the articles that did not enter the review process due to unavailability of their full-texts or having a very small sample size, no clear positive effect of broccoli on inhibiting H. pylori infection in humans had been reported. Conclusion: Due to the lack of optimal results from broccoli consumption for the control of H. pylori infection in humans, it is recommended that longer studies with sufficient sample size and appropriate dose of broccoli along with standard treatment be performed in the future.

scholarly journals Effectiveness of Music Therapy for the Treatment of Movement Disorders in Parkinson’s Disease

2021 ◽  
Author(s):  
Emily Calmon Londero ◽  
Ana Beatriz Cazé Cerón
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Clinical Trials ◽  
Music Therapy ◽  
Sample Size ◽  
Movement Disorders ◽  
Randomized Clinical Trials ◽  
Small Sample ◽  
Motor Deficit ◽  
Auditory Stimuli

Introduction: Body movement is synchronized by external rhythmic stimuli in conjunction with physiological control, based on an internal timing process. In this perspective, music therapy can be a potential therapeutic tool for the treatment of individuals with movement disorders as it bypasses an internal rhythm motor deficit. Objective: To evaluate the benefit of music therapy in the treatment of movement disorders in patients with Parkinson’s disease (PD). Methods: This study is a literary review, which used the PubMed platform, in April 2021, with the formula: (MOVEMENT DISORDERS) AND (MUSIC THERAPY). As search criteria, articles were selected from meta-analyzes, reviews and randomized clinical trials, published in the last 10 years, in English and studies carried out in humans. Results: 21 articles were found, 6 articles were selected according to the eligibility criteria. Most studies show an improvement in movement disorders when rhythmic musical stimuli are associated with motor interventions, such as the use of treadmills. A randomized clinical trial with 50 patients with idiopathic PD was divided into two groups, one with a treadmill and with rhythmic auditory stimuli and another with a treadmill and without auditory stimuli. Among the outcomes analyzed, the improvement in movement speed was the most beneficial aspect, with an improvement in quality of life and cognitive functions. Conclusion: It is evident that the use of music therapy in the treatment of movement disorders in patients with PD improves motor symptoms. However, the studies have a small sample size and differ in terms of the method of music therapy, the period of intervention and the scales used to assess improvement. Therefore, it is important that randomized, multicenter clinical trials with a larger sample size are carried out to prove the benefits of music therapy in a patient with Parkinson’s disease.

Sign in / Sign up

Export Citation Format

Share Document