Clinical trials: specific problems associated with the use of a placebo-control group

1995 ◽  
Vol 73 (8) ◽  
Author(s):  
T.J.M. Cleophas
Keyword(s):  
Clinical Trials ◽  
Control Group ◽  
Placebo Control ◽  
Placebo Control Group

scholarly journals Effectiveness of Dentist-Prescribed, Home-Applied Tooth Whitening, A Meta-analysis

1999 ◽  
Vol 1 (4) ◽  
pp. 34-49 ◽  
Author(s):  
Richard Niederman ◽  
Maggie C. Tantraphol ◽  
Patricia Slnin ◽  
Catherine Hayes ◽  
Suzy Conway
Keyword(s):  
Clinical Trials ◽  
Meta Analysis ◽  
Control Group ◽  
Placebo Control ◽  
List Type ◽  
Tooth Whitening ◽  
Clinical Applicability ◽  
Placebo Control Group ◽  
The People ◽  
Shade Guide

Abstract Introduction Common clinical experience suggests that tooth whitening agents are 100% effective. This study uses meta-analysis of data from published randomized controlled clinical trials to determine the efficacy of tooth whitening agents. Methods A MEDLINE search strategy was developed and implemented to systematically identify clinical trials on dentist-prescribed, home-applied tooth whitening agents, using 10% carbamide peroxide, published between 1989-1999. Inclusion criteria (e.g., in English, human clinical trials) and exclusion criteria (e.g., not placebo controlled) were established and clinical trials that met these criteria were critically appraised for validity and clinical applicability. Meta-analysis was then used to quantitatively integrate the findings. Results Seven studies were identified that met the inclusion and validity criteria. These studies indicated that: Whitening results in a significant mean change of 6 4 shade guide units (p < 0.01), while the placebo control group exhibited little change (0.7 0.6, p > 0.05). 93% of the bleached patients exhibited 2 shade guide unit change, while 20% of the placebo control group exhibited this change. The brand of bleaching agent had a significant effect on tooth whitening, but the daily application time and duration of treatment did not. Whitening is maintained for 6 months for 1/2 of the people treated. Neither gingival indices nor plaque indices were adversely or favorably affected by bleaching. Clinical Applicability The data from the reviewed studies indicate that rather than being 100% effective, on average: 73% (93% for bleached group minus 20% placebo group) of people who whiten their teeth will exhibit a whitening that is 2 shade guide units greater than the placebo. 20% of the people who use dentist-prescribed, home-applied bleaching will achieve a mean whitening effect of 5 shade guide units. Re-treatment for 50% of people may be necessary to maintain this effect longer than 6 months. The methods used here are Internet applicable for other clinical topics.

ESTIMATING EFFECTS OF SYSTEMATIC TREATMENT ON RENAL FAILURE AND DEATH WITHOUT A PARALLEL PLACEBO CONTROL GROUP

Nephrology ◽  
2000 ◽  
Vol 5 (3) ◽  
pp. A97-A97
Author(s):  
Hoy We ◽  
Baker P ◽  
Wang Z ◽  
Cass A ◽  
Mathews Jd ◽  
...  
Keyword(s):  
Renal Failure ◽  
Control Group ◽  
Placebo Control ◽  
Systematic Treatment ◽  
Placebo Control Group

Use of a placebo in clinical trials

1998 ◽  
Vol 13 (5) ◽  
pp. 254-263 ◽  
Author(s):  
G Emilien ◽  
JM Maloteaux ◽  
A Seghers ◽  
G Charles
Keyword(s):  
Clinical Trials ◽  
Placebo Response ◽  
Drug Efficacy ◽  
Placebo Treatment ◽  
High Response Rate ◽  
Experimental Methodology ◽  
Necessary Condition ◽  
Control Group ◽  
Placebo Control ◽  
Experimental Drug

SummaryThe use of a placebo control group in the evaluation of a new product is today considered by most as a necessary condition of experimental drug research. Placebo response is an essential consideration in all clinical trials. If not properly controlled, incorrect and dangerous conclusion may be inferred for a product efficacy and safety profile. However, the inclusion of a placebo group in clinical trials in neuropsychiatric research raises several ethical and scientific questions. Whereas in certain indications, such as suicidal patients and severe and psychotic depression, the use of a placebo is generally not accepted, it is difficult to assess drug efficacy. This article discusses the concept of placebo in clinical trials, the occurrence of adverse events after placebo treatment and the high response rate of placebo in neuropsychiatric clinical research. The experimental methodology to adequately control all the factors involved is also analysed and discussed.

scholarly journals Efficacy and Safety of Ejiao (Asini Corii Colla) in Women With Blood Deficient Symptoms: A Randomized, Double-Blind, and Placebo-Controlled Clinical Trial

2021 ◽  
Vol 12 ◽  
Author(s):  
Li Zhang ◽  
Zhongju Xu ◽  
Tao Jiang ◽  
Jialu Zhang ◽  
Pinxian Huang ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Blood Cell ◽  
Control Group ◽  
Placebo Control ◽  
Controlled Clinical Trial ◽  
Efficacy And Safety ◽  
Double Blind ◽  
Placebo Control Group ◽  
Sf 36

Equus asinus L [Equidae; Asini Corii Colla] (donkey-hide gelatin, Ejiao), a well-known traditional Chinese medicine, has been widely used to nourish the blood, especially for women. The aim of this study was to assess the efficacy and safety of Ejiao in blood-deficient patients. A total of 210 participants were recruited and randomly allocated into the placebo control group and Ejiao-treated group (6 g/day). The primary outcomes on the efficacy of Ejiao included traditional Chinese medicine symptom scores, blood indicators, and SF-36. The secondary outcomes were changes in fireness and safety evaluation. Results showed that Ejiao treatment for 8 weeks had significantly improved dizziness symptoms. Among the tested 24 blood biochemical parameters, the hematocrit and red blood cell numbers decreased in the placebo control group, but decreased significantly less in the Ejiao treatment group. The white blood cell and neutrophil counts increased in the Ejiao group but were within the normal range. In addition, the quality of life improved as the scores in SF-36 domains were significantly higher in the Ejiao group. At the same time, there was no significant change in the fire–heat symptoms score or other safety parameters. Considering all these, our study showed that Ejiao has a promising effect in women suffering from blood deficiency without obvious adverse effects.

Sulfinpyrazone And Prevention Of Postoperative Deep Venous Thrombosis(DVT)

1981 ◽  
Author(s):  
G Arapakis ◽  
A Trovas ◽  
G Orphanoudakis ◽  
P Vassilikos
Keyword(s):  
Arterial Thrombosis ◽  
Statistical Significance ◽  
Group Analysis ◽  
Control Group ◽  
Placebo Control ◽  
Double Blind Trial ◽  
Double Blind ◽  
Placebo Control Group ◽  
Postoperative Deep Venous Thrombosis ◽  
Surgical Operations

Though the antithrombotic properties of sulfinpyrazone (SP) in arterial thrombosis have been documented, its value in phlebothrombosis remains uncertain. In this randomized double-blind trial, the effect of SP (500mg I.M. twice daily for the first 10 postoperative days) on postoperative DVT was compared with a placebo control group. 96 (65 male and 31 female) patients 41 to 83 years of age undergoing major surgical operations were included in the trial. The composition of the two groups (treated and placebo) were homogenious regarding age, sex and type of operation (0,30<p<0,50). The incidence of DVT was estimated clinically and isotopically by the 125I-labelled figrinogen test.No clinical phlebothrombosis was observed in either group but DVT was detected isotopically in 4 (8,3%) out of 48 in the placebo and in 7 (14,5%) of the 48 in the SP group. Analysis by the x2 showed no statistical significance in the prevalence of postoperative DVT between the two groups (x2<x20,30/1). These results suggest that SP has no place in the prevention of postoperative DVT.

scholarly journals Improving mental health and physiological stress responses in mothers following traumatic childbirth and in their infants: study protocol for the Swiss TrAumatic biRth Trial (START)

BMJ Open ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. e032469 ◽  
Author(s):  
Vania Sandoz ◽  
Camille Deforges ◽  
Suzannah Stuijfzand ◽  
Manuella Epiney ◽  
Yvan Vial ◽  
...  
Keyword(s):  
Infant Development ◽  
Primary Outcome ◽  
Physiological Stress ◽  
Control Group ◽  
Placebo Control ◽  
Ptsd Symptoms ◽  
Intrusive Memories ◽  
Placebo Control Group ◽  
Psychological Vulnerability ◽  
Traumatic Childbirth

IntroductionEmergency caesarean section (ECS) qualifies as a psychological trauma, which may result in postnatal post-traumatic stress disorder (PTSD). Maternal PTSD may not only have a significant negative impact on mother–infant interactions, but also on long-term infant development. The partner’s mental health may also affect infant development. Evidence-based early interventions to prevent the development of postpartum PTSD in mothers are lacking. Immediately after a traumatic event, memory formation is vulnerable to interference. There is accumulating evidence that a brief behavioural intervention including a visuospatial task may result in a reduction in intrusive memories of the trauma.Methods and analysisThis study protocol describes a double-blind multicentre randomised controlled phase III trial testing an early brief maternal intervention including the computer game ‘Tetris’ on intrusive memories of the ECS trauma (≤1 week) and PTSD symptoms (6 weeks, primary outcome) of 144 women following an ECS. The intervention group will carry out a brief behavioural procedure including playing Tetris. The attention-placebo control group will complete a brief written activity log. Both simple cognitive tasks will be completed within the first 6 hours following traumatic childbirth. The intervention is delivered by midwives/nurses in the maternity unit.The primary outcome will be differences in the presence and severity of maternal PTSD symptoms between the intervention and the attention-placebo control group at 6 weeks post partum. Secondary outcomes will be physiological stress and psychological vulnerability, mother–infant interaction and infant developmental outcomes. Other outcomes will be psychological vulnerability and physiological regulation of the partner and their bonding with the infant, as well as the number of intrusive memories of the event.Ethics and disseminationEthical approval was granted by the Human Research Ethics Committee of the Canton de Vaud (study number 2017–02142). Dissemination of results will occur via national and international conferences, in peer-reviewed journals, public conferences and social media.Trial registration numberNCT 03576586.

Alcohol and Aggression

2007 ◽  
Vol 18 (7) ◽  
pp. 649-655 ◽  
Author(s):  
Peter R. Giancola ◽  
Michelle D. Corman
Keyword(s):  
Working Memory ◽  
Attention Allocation ◽  
Control Group ◽  
Placebo Control ◽  
Sequential Order ◽  
Allocation Model ◽  
Placebo Control Group ◽  
Electric Shocks ◽  
Moderate Load ◽  
Laboratory Task

This article presents the first systematic test of the attention-allocation model for alcohol-related aggression. According to this model, alcohol has a “myopic” effect on attentional capacity that presumably facilitates aggression by focusing attention on more salient provocative, rather than less salient inhibitory, cues in hostile situations. Aggression was assessed using a laboratory task in which mild electric shocks were received from, and administered to, a fictitious opponent. Study 1 demonstrated that a moderate-load cognitive distractor suppressed aggression in intoxicated subjects (to levels even lower than those exhibited by a placebo control group). Study 2 assessed how varying the magnitude of a distracting cognitive load affected aggression in the alcohol and placebo conditions. Results indicated that the moderate-load distraction used in Study 1 (i.e., holding four elements in sequential order in working memory) suppressed aggression best. Cognitive loads of larger and smaller magnitudes were not successful in attenuating aggression.

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