Abstract:
:Modified Zelen's approach is a randomization technique useful in multi-center trials where balance in treatment assignments within a center is desired. It has great balancing properties in a study with equal allocation to several treatment arms. This technique can also be used in studies with unequal allocation, where it would provide an allocation ratio close to the targeted one within centers as well as across centers. However, the implementation of the modified Zelen's approach for unequal allocation involves more than just imposing a constraint on within-center imbalance in treatment assignments, as is the case with equal allocation. Failure to account for this might provide a potential for accidental bias and (even in a double-blind study) selection and evaluation bias. The naive expansion of the modified Zelen's approach to unequal allocation can also lead to a shift in the re-randomization distribution of the between-group difference in treatment means. This paper will explain why and will offer an easy way to expand the modified Zelen's approach to unequal allocation that allows one to avoid these issues. The expansion to unequal allocation of another very useful in multi-center trials technique where partial blocks of supplies are sent to the centers will be offered.
journal_name
Contemp Clin Trialsjournal_title
Contemporary clinical trialsauthors
Kuznetsova OM,Tymofyeyev Ydoi
10.1016/j.cct.2011.08.006subject
Has Abstractpub_date
2011-11-01 00:00:00pages
962-72issue
6eissn
1551-7144issn
1559-2030pii
S1551-7144(11)00207-2journal_volume
32pub_type
杂志文章,评审abstract:INTRODUCTION:Youth in disadvantaged urban areas are frequently exposed to chronic stress and trauma, including housing instability, neighborhood violence, and other poverty-related adversities. These exposures increase risk for emotional, behavioral, and academic problems and ultimately, school dropout. Schools are a p...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2019.105895
更新日期:2020-03-01 00:00:00
abstract::Cluster randomised controlled trials for health promotion, education, public health or organisational change interventions are becoming increasingly common to inform evidence-based policy. However, there is little published methodological evidence on recruitment strategies for primary care population clusters. In this...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2006.08.004
更新日期:2007-05-01 00:00:00
abstract:BACKGROUND:Laxatives are much utilized, but few clinical trials assessed the efficacy of phytotherapics in the functional constipation. AIM:The aim of this study was to evaluate the efficacy of the tincture of jalapa in the treatment of patients with functional constipation. METHODS:Double-blind, randomized, placebo-...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2010.10.011
更新日期:2011-03-01 00:00:00
abstract::Knee osteoarthritis (OA) is a leading cause of late life pain and disability, and non-Hispanic black (NHB) adults experience greater OA-related pain and disability than non-Hispanic whites (NHWs). Recent evidence implicates psychosocial stress, cognitive-attentional processes, and altered central pain processing as co...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2020.106159
更新日期:2020-11-01 00:00:00
abstract::This randomized, controlled trial tested the effectiveness of a nurse-run, telephone-based intervention to improve lipid control in patients with diabetes. Our patient population is predominantly low-income and Latino. Using our diabetes registry, we randomly assigned 381 patients to continue with their usual care and...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2008.05.011
更新日期:2008-09-01 00:00:00
abstract:BACKGROUND:Patients with progressive kidney disease experience increasing physiologic and psychosocial stressors and declining health-related quality of life (HRQOL). METHODS:We conducted a randomized, active-controlled, open-label trial to test whether a Mindfulness-based Stress Reduction (MBSR) program delivered in ...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2017.03.014
更新日期:2017-06-01 00:00:00
abstract:BACKGROUND:Functional dyspepsia (FD) is a common problem affecting up to 10-25% of individuals. FD accounts for significant health care costs and affects quality of life but has no definitive treatment. OBJECTIVES:The Functional Dyspepsia Treatment Trial (FDTT) aims to test whether treatment with an antidepressant (am...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2012.02.002
更新日期:2012-05-01 00:00:00
abstract::Although the Diabetes Prevention Program (DPP) developed a lifestyle weight loss intervention that has been demonstrated to prevent type 2 diabetes in high-risk individuals, it has yet to be widely adopted at the community level. The Healthy Living Partnership to Prevent Diabetes study (HELP PD) was designed to transl...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2009.09.002
更新日期:2010-01-01 00:00:00
abstract:BACKGROUND:Colorectal cancer (CRC) screening by annual fecal immunochemical test (FIT) is an accessible and cost-effective strategy to lower CRC incidence and mortality. However, this mode of screening depends on follow-up colonoscopy after a positive FIT result. Unfortunately, nearly one-half of FIT-positive patients ...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2019.105920
更新日期:2020-02-01 00:00:00
abstract::This pilot study examined knowledge, understanding and perceived acceptability of key methodological concepts in clinical trials among injecting drug users (IDUs) in Sydney, Australia. Participants were clinical trial-experienced (n = 17) and trial-naïve (n = 99) IDUs recruited from community needle and syringe progra...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2009.04.002
更新日期:2009-09-01 00:00:00
abstract::The prevalence of obesity is high resulting from chronic imbalances between energy intake and expenditure. On the expenditure side, regular exercise is associated with health benefits, including enhanced brain function. The benefits of exercise are not immediate and require persistence to be realized. Brain regions as...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2013.11.007
更新日期:2014-01-01 00:00:00
abstract:INTRODUCTION:In promoting the health of chronically ill children, the hospital should help children cope both medically and psychosocially with their disease. The University Children's Hospital of Nancy proposes adapted physical activity for hospitalized children, but the practice during hospitalization is not well dev...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2009.12.003
更新日期:2010-03-01 00:00:00
abstract:INTRODUCTION:Robotic assistance during laparoscopic surgery for pelvic organ prolapse rapidly disseminated across the United States without level I data to support its benefit over traditional open and laparoscopic approaches [1]. This manuscript describes design and methodology of the Abdominal Colpopexy: Comparison o...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,多中心研究,随机对照试验
doi:10.1016/j.cct.2012.05.007
更新日期:2012-09-01 00:00:00
abstract:BACKGROUND:The addition of specialty palliative care to standard oncology care improves outcomes for patients with advanced cancer and their caregivers, but many lack access to specialty care services. Primary palliative care-meaning basic palliative care services provided by clinicians who are not palliative care spec...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2017.01.005
更新日期:2017-03-01 00:00:00
abstract::The prevalence of type 2 diabetes continues to increase in minority and underserved patients, who are also more likely to have poorer control of diabetes and related risk factors for complications. Although the Look AHEAD trial has demonstrated improved risk factor control among overweight or obese diabetes patients w...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2016.12.005
更新日期:2017-02-01 00:00:00
abstract::It is of vital importance to the success of a randomized clinical trial to maintain the balance of baseline characteristics (covariates) that could potentially confound the outcomes of the trial. Various randomization methods have been proposed to increase the likelihood of having balanced covariates at the end of a t...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2011.03.004
更新日期:2011-07-01 00:00:00
abstract:BACKGROUND:Atorvastatin and metformin are known energy restricting mimetic agents that act synergistically to produce molecular and metabolic changes in advanced prostate cancer (PCa). This trial seeks to determine whether these drugs favourably alter selected parameters in men with clinically-localized, aggressive PCa...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2016.06.014
更新日期:2016-09-01 00:00:00
abstract::The Ready Steady 3.0 trial is designed to test the main and interactive effects of two behavior change intervention components, within an 8-week physical activity intervention, on older adults' physical activity (PA). Each component is comprised of behavior change strategies that emphasize two different evidence-based...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2020.106238
更新日期:2020-12-05 00:00:00
abstract:BACKGROUND:Despite controversy about paying research subjects, little is known about actual practices in the U.S., including what type of studies offer payment, to what type of subjects, and how amounts are determined. OBJECTIVE:To document current U.S. practices regarding payment to research subjects. METHODS:The pr...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2005.02.003
更新日期:2005-06-01 00:00:00
abstract::Hepatitis C virus (HCV) is a leading cause of chronic liver disease. The natural history of HCV infection is heterogeneous, and a person infected with HCV can clear the virus or progress to a chronic infection. The chronic infection can remain asymptomatic for decades before the development of liver cirrhosis and/or c...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2008.03.006
更新日期:2008-09-01 00:00:00
abstract::Evaluation of time to event outcomes usually is examined by the Kaplan-Meier method and Cox proportional hazards models. We developed a modified statistical model based on histologic grade and other variables to describe the time-dependent outcome for autologous stem cell transplant (autotransplant) performed for non-...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2007.07.005
更新日期:2008-03-01 00:00:00
abstract::Osteoarthritis (OA) is the most common chronic condition and principal cause of disability among older adults. The current obesity epidemic has contributed to this high prevalence rate. Fortunately both OA symptoms and obesity can be ameliorated through lifestyle modifications. Physical activity (PA) combined with wei...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2013.11.014
更新日期:2014-03-01 00:00:00
abstract:BACKGROUND:Suboptimal diet and inactive lifestyle are among the most prevalent preventable causes of premature death. Interventions that target multiple behaviors are potentially efficient; however the optimal way to initiate and maintain multiple health behavior changes is unknown. OBJECTIVE:The Make Better Choices 2...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2015.01.009
更新日期:2015-03-01 00:00:00
abstract:BACKGROUND:Mindfulness-based relapse prevention (MBRP) is a method that combines cognitive behavioral relapse prevention with mindfulness practice. Research suggests that MBRP can effectively reduce withdrawal/craving in people with substance use disorder (SUD). An important part of MBRP is to practice mindfulness medi...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2018.04.006
更新日期:2018-07-01 00:00:00
abstract:BACKGROUND:Formation of diet and physical activity habits begins during early childhood. However, many preschool-aged children in the United States do not achieve recommendations for a nutritious diet or active lifestyle. Two important spheres of influence, home and child care, could ensure that children receive consis...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2017.11.007
更新日期:2018-01-01 00:00:00
abstract:INTRODUCTION:Excessive recreational screen time (i.e., screen use for entertainment) is a global public health issue associated with adverse mental and physical health outcomes. Considering the growing popularity of screen-based recreation in adolescents, there is a need to identify effective strategies for reducing sc...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2014.12.001
更新日期:2015-01-01 00:00:00
abstract:BACKGROUND:Evidence suggests that periodontitis is associated with prevalent and incident type 2 diabetes mellitus (T2DM), raising the question of whether periodontitis treatment may improve glycemic control in patients with T2DM. Meta-analyses of mostly small clinical trials suggest that periodontitis treatment result...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,多中心研究,随机对照试验
doi:10.1016/j.cct.2013.09.010
更新日期:2013-11-01 00:00:00
abstract:INTRODUCTION:Breast cancer survivors face dual challenges: long term sequelae of treatment, and risk of recurrent disease. Obesity and a sedentary lifestyle complicate both challenges. The WISER Survivor trial assessed the effects of exercise and/or weight-loss on lymphedema, biomarkers of breast cancer recurrence, and...
journal_title:Contemporary clinical trials
pub_type: 杂志文章,随机对照试验
doi:10.1016/j.cct.2017.07.017
更新日期:2017-10-01 00:00:00
abstract::Researchers have long sought to find combinations of cancer drugs that might achieve synergy. However, while observed in some preclinical tumor models, synergistic effects are rarely seen in clinical trials. In fact, growing evidence in clinical trial data shows that the treatment effect of most approved combination t...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2020.106126
更新日期:2020-11-01 00:00:00
abstract::A response-adaptive randomization (RAR) design refers to the method in which the probability of treatment assignment changes according to how well the treatments are performing in the trial. Holding the promise of treating more patients with the better treatments, RARs have been successfully implemented in clinical tr...
journal_title:Contemporary clinical trials
pub_type: 杂志文章
doi:10.1016/j.cct.2014.11.006
更新日期:2015-01-01 00:00:00