Current and future challenges in the design and analysis of cluster randomization trials

A study protocol for a cluster randomized pragmatic trial for comparing strategies for implementing primary HPV testing for routine cervical cancer screening in a large health care system

BACKGROUND

Limited guidance exists regarding implementation strategies that best facilitate cancer screening practice substitution and achieve optimal stakeholder-centered outcomes. Here we describe the protocol for a randomized pragmatic trial comparing two implementation strategies to facilitate substitution of primary HPV screening for Pap and HPV co-testing to perform routine cervical cancer screening of women aged 30-65 years at Kaiser Permanente Southern California (KPSC).

METHODS

Twelve service areas within KPSC will be randomized to a "centrally-administered system-wide implementation + local-tailored implementation" strategy or a "centrally-administered system-wide implementation only" strategy. The centrally-administered strategy comprises clinician and staff educational activities. Sites in the local-tailored arm will then conduct a structured local needs assessment followed by site-specific selection and deployment of implementation interventions. Surveys and interviews will be conducted among women and providers from the primary care and ob/gyn departments prior to the system-wide transition, shortly after the transition, and after the completion of local-tailored interventions. A stakeholder advisory committee will assist with study design, defining stakeholder-centered outcomes, and developing data collection tools.

RESULTS

The primary outcome of interest is uptake of primary HPV screening. Secondary provider-centered outcomes include provider knowledge, delivery of patient education, satisfaction with the practice substitution process, and resistance to primary HPV screening. Secondary patient-centered outcomes include patient knowledge, stigma, and satisfaction with the screening process. Intervention fidelity will also be measured via surveys.

CONCLUSIONS

Findings from this study will help inform future use of a local-tailored implementation strategy for adopting primary HPV screening at large health care systems. Findings may also be applicable to other types of practice substitution.

Diagnostic Strategy for Suspected Pulmonary Embolism in Emergency Departments Based on the 4-Level Pulmonary Embolism Clinical Probability Score: Study Protocol of SPEED&PEPS Trial

Introduction: Several strategies have been devised to safely limit the use of thoracic imaging in patients suspected of pulmonary embolism (PE). However, they are based on different rules for clinical probability (CP) assessment, rendering their combination difficult. The four-level pulmonary embolism probability score (4PEPS) allows the combination of all other strategies using a single CP assessment. Methods and analysis: Pragmatic cluster-randomized trial in 20 EDs. Patients with suspected PE will be included and followed for 90 days (number of patients to be included: 2560, 1280 in each arm). Ten centers will be allocated to the control group where physicians will be free to do as they see fit but they will be given the recommendation to apply a validated strategy. Ten centers will be allocated to the interventional group where the physicians will be given the recommendation to apply the 4PEPS strategy. The primary objective will be to demonstrate that the application of the 4PEPS strategy by the emergency physicians, in comparison to current practices, (i) does not increase the risk of serious events related to diagnostic strategies and (ii) significantly reduces the use of thoracic imaging. Ethics and dissemination: The study will be submitted for approval to an institutional ethics review board for all participating centers. If successful, the SPEED&PEPS trial will have an important impact for patients suspected of PE limiting their irradiation and for public health in substantial savings in terms of the direct cost of diagnostic investigations and the indirect cost of hospitalizations due to waiting times or delayed harmful effects. Funding: This work is funded by a French Public Health grant (PREPS-N 2019). The funding source plays no role in the study design, data collection, analysis, interpretation or the writing of the manuscript. Trial registration: ongoing. Trial status: not started.

Cluster-randomized trials of cancer screening interventions: Has use of appropriate statistical methods increased over time?

BACKGROUND

In a cluster randomized trial, groups of individuals (e.g., clinics, schools) are randomized to conditions. The design and analysis of cluster randomized trials can require more care than individually randomized trials. Past reviews have noted deficiencies in the use of appropriate statistical methods for such trials.

METHODS

We reviewed cluster randomized trials of cancer screening interventions published 1995-2019 to determine whether appropriate statistical methods had been used for sample size calculation and outcome analysis and whether they reported intraclass correlation coefficient (ICC) values. This work expanded a previous review of articles published 1995-2010.

RESULTS

Our search identified 88 articles published 1995-2020 that reported outcomes of cluster randomized trials of breast, cervix, and colorectal cancer screening interventions. There was increased reporting of the trials' sample size calculations over time, with the percentage increasing from 31% in 1995-2004 to 77% in 2014-2019. However, the percentage of calculations failing to account for cluster randomization did not change over time and was 17% of studies in 2014-2019. There was a nonsignificant trend towards increased use of outcome analysis methods that accounted for the cluster randomized design. However, in lower impact journals, use of appropriate analysis methods was only 80% in 2014-2019. Only 33% of studies reported ICC values in 2014-2019.

CONCLUSION

For cluster randomized trials with cancer screening outcomes, there have been improvements in the reporting of sample size calculations but methodological and reporting deficiencies persist. Efforts to disseminate, adopt and report the use of appropriate statistical methodologies are still needed.

The Families First Program to Prevent Child Abuse: Results of a Cluster Randomized Controlled Trial in West Java, Indonesia

The Families First parenting program is a 10-week paraprofessional-administered adaptation of the Positive Discipline in Everyday Parenting program for West Java, Indonesia. It has not been tested in a randomized controlled trial. The objective was to evaluate the effects of Families First on physical and emotional punishment. We conducted a cluster randomized controlled trial and randomly assigned 20 rural and urban villages in West Java, Indonesia, to intervention or waitlist. Caregivers of children aged 0-7 years in intervention villages received Families First. Between 2017 and 2018, measurements were taken before randomization, immediately post-intervention, and 6 months post-intervention. Primary outcome was presence versus absence of caregiver-reported physical or emotional punishment immediately post-intervention. Intention-to-treat regression models accounted for clustering within villages and were run to compare between groups. Participants and study personnel could not be blinded. There were 374 caregivers in the 10 intervention villages and 362 in the 10 waitlist villages included in the trial and in outcome analyses. The intervention did not result in a lower proportion of intervention families using punishment immediately post-intervention (odds ratio [OR] for physical or emotional punishment immediately post intervention = 1.20 (95% CI 0.79-1.82). There were no significant differences for positive and involved parenting, setting limits, and opinion on discipline, but caregivers in the intervention group had significantly lower odds of using positive discipline (OR = 0.65 (95% CI 0.53-0.80). Families First did not prevent punishment in a setting with low levels of reported punishment but should be tested in a setting with higher levels or among people selected for risk or presence.

Statistical power and sample size requirements to detect an intervention by time interaction in four-level longitudinal cluster randomized trials

Cluster/group randomized controlled trials (CRTs) have a long history in the study of health sciences. CRT is a special type of intervention trial in which a complete group is randomly assigned to a study condition (or intervention). It is typically performed when individual randomization is difficult/impossible without substantial risk of contamination across study arms or prohibitive from the cost or group dynamics point of view. In this article, the aim is to design and analyze four-level longitudinal cluster randomized trials. The main interest here is to study the difference between treatment groups over time for such a four-level hierarchical data structure. This work is motivated by a real-life study for education based HIV prevention. Such trials are not only popular for administrative convenience, ethical considerations, subject compliance, but also help to reduce contamination bias. A random intercept mixed effects linear regression including a time by intervention interaction is used for modeling. Closed form expression of the power function to detect the interaction effect is determined. Sample size equations depend on correlation among schools but not on correlations among classes or students while, the power function depends on the product of number of units at different levels. Optimal allocation of units under a fixed cost by minimizing the expected standardized variance is also determined and are shown to be independent of correlations among units in any level. Results of detailed simulation studies find the theoretical power estimates based on the derived formulae close to the empirical estimates.

Evaluating Diuretics in Normal Care (EVIDENCE): protocol of a cluster randomised controlled equivalence trial of prescribing policy to compare the effectiveness of thiazide-type diuretics in hypertension

INTRODUCTION

Healthcare systems must use treatments that are effective and safe. Regulators licensed many currently used older medications before introducing the stringent evidential requirements imposed on modern treatments. Also, there has been little encouragement to carry out within-class, head-to-head comparisons of licensed medicines. For commonly prescribed drugs, even small differences in effectiveness or safety could have significant public health implications. However, conventional clinical trials that randomise individual subjects are costly and unwieldy. Such trials are also often criticised as having low external validity. We describe an approach to rapidly generate externally valid evidence of comparative safety and effectiveness using the example of two widely used diuretics for the management of hypertension.

METHODS AND ANALYSIS

The EVIDENCE (Evaluating Diuretics in Normal Care) study has a prospective, cluster-randomised, open-label, blinded end-point design. By randomising prescribing policy in primary care practices, the study compares the safety and effectiveness of commonly used diuretics in treating hypertension. Participating practices are randomised 1:1 to a policy of prescribing either indapamide or bendroflumethiazide when clinically indicated. Suitable patients who are not already taking the policy diuretic are switched accordingly. All patients taking the study medications are written to explaining the rationale for changing the prescribing policy and notifying them they can opt-out of any switch. The prescribing policies' effectiveness and safety will be compared using rates of major adverse cardiovascular events (hospitalisation with myocardial infarction, heart failure or stroke or cardiovascular death), routinely collected in national healthcare administrative datasets. The study will seek to recruit 250 practices to provide a study population of approximately 50,000 individuals with a mean follow-up time of two years. A primary intention-to-treat time-to-event analysis will be used to estimate the relative effect of the two policies.

ETHICS AND DISSEMINATION

EVIDENCE has been approved by the East of Scotland Research Ethics Service (17/ES/0016, current approved protocol version 5, 26 August 2021). The results will be disseminated widely in peer reviewed journals, guideline committees, National Health Service (NHS) organisations and patient groups.

TRIAL REGISTRATION

ISRCTN 46635087 . Registered on 11 August 2017 (pre-recruitment).

Women's experiences of receiving information about and consenting or declining to participate in a randomized controlled trial involving episiotomy in vacuum-assisted delivery: a qualitative study

Background

Information about and invitation to participate in a clinical trial involving an intervention during childbirth may cause fear or worry in pregnant women. The aim of this study was to describe nulliparous women’s experiences of receiving an invitation to participate in a randomized controlled trial (RCT) of lateral episiotomy versus no episiotomy in vacuum-assisted delivery (EVA trial).

Methods

This qualitative study was nested in the ongoing EVA trial. Data were collected through semistructured telephone interviews with 23 women regarding their experiences of the information and invitation to participate in the EVA trial. Interviews were audio-recorded and transcribed verbatim. A qualitative content analysis was used to analyse the interview contents.

Results

Three main experience categories were identified among the participants. “Timing of trial information and understanding” revealed that women preferred to obtain information about the trial early on during pregnancy. “Reasons to consent to or decline participation in the trial” encompassed a variety of reasons for women to consent, such as goodwill for science or personal benefits, or to decline, such as not wanting to be randomized or fear of increased risk of having a vacuum-assisted delivery. “Thoughts evoked regarding childbirth” were diverse, ranging from not being affected at all to having increased anxiety.

Conclusions

The women’s experience of receiving an invitation to participate in an RCT of episiotomy in vacuum-assisted delivery varied widely, from immediately giving consent without further worries to increased anxiety or declining participation. Early and personal information with time for reflection was considered most satisfactory.

Trial registration

ClinicalTrials.govNCT02643108. Registered on December 28, 2015. The Lateral Episiotomy or Not in Vacuum Assisted Delivery in Non-parous Women (EVA) trial was registered at www.clinicaltrials.gov.

When should matching be used in the design of cluster randomized trials?

For cluster randomized trials (CRTs) with a small number of clusters, the matched-pair (MP) design, where clusters are paired before randomizing one to each trial arm, is often recommended to minimize imbalance on known prognostic factors, add face-validity to the study, and increase efficiency, provided the analysis recognizes the matching. Little evidence exists to guide decisions on when to use matching. We used simulation to compare the efficiency of the MP design with the stratified and simple designs, based on the mean confidence interval width of the estimated intervention effect. Matched and unmatched analyses were used for the MP design; a stratified analysis was used for the stratified design; and analyses without and with post-stratification adjustment for factors that would otherwise have been used for restricted allocation were used for the simple design. Results showed the MP design was generally the most efficient for CRTs with 10 or more pairs when the correlation between cluster-level outcomes within pairs (matching correlation) was moderate to strong (0.3-0.5). There was little gain in efficiency for the MP or stratified designs compared to simple randomization when the matching correlation was weak (0.05-0.1). For trials with four pairs of clusters, the simple and stratified designs were more efficient than the MP design because greater degrees of freedom were available for the analysis, although an unmatched analysis of the MP design recovered precision for weak matching correlations. Practical guidance on choosing between the MP, stratified, and simple designs is provided.

Imputing intracluster correlation coefficients from a posterior predictive distribution is a feasible method of dealing with unit of analysis errors in a meta-analysis of cluster RCTs

BACKGROUND

Incorporating cluster randomized trials (CRTs) into meta-analyses is challenging because appropriate standard errors of study estimates accounting for clustering are not always reported. Systematic reviews of CRTs often use a single constant external estimate of the intraclass correlation coefficient (ICC) to adjust study estimate standard errors and facilitate meta-analyses; an approach that fails to account for possible variation of ICCs among studies and the imprecision with which they are estimated. Using a large systematic review of the effects of diabetes quality improvement interventions, we investigated whether we could better account for ICC variation and uncertainty in meta-analyzed effect estimates by imputing missing ICCs from a posterior predictive distribution constructed from a database of relevant ICCs.

METHODS

We constructed a dataset of ICC estimates from applicable studies. For outcomes with two or more available ICC estimates, we constructed posterior predictive ICC distributions in a Bayesian framework. For a selected continuous outcome, glycosylated hemoglobin (HbA1c), we compared the impact of incorporating a single constant ICC versus imputing ICCs drawn from the posterior predictive distribution when estimating the effect of intervention components on post treatment mean in a case study of diabetes quality improvement trials.

RESULTS

Using internal and external ICC estimates, we were able to construct a database of 59 ICCs for 12 of the 13 review outcomes (range 1-10 per outcome) and estimate the posterior predictive ICC distribution for 11 review outcomes. Synthesized results were not markedly changed by our approach for HbA1c.

CONCLUSION

Building posterior predictive distributions to impute missing ICCs is a feasible approach to facilitate principled meta-analyses of cluster randomized trials using prior data. Further work is needed to establish whether the application of these methods leads to improved review inferences for different reviews based on different factors (e.g., proportion of CRTs and CRTs with missing ICCs, different outcomes, variation and precision of ICCs).

An investigation of the effect of smartphone-based pain management application on pain intensity and the quality-of-life dimensions in adolescents with chronic pain: a cluster randomized parallel-controlled trial

INTRODUCTION

Chronic pain negatively affects adolescents' quality of life. Therefore, it is important to seek for ways to effectively manage pain, which may, in turn, promote quality-of-life dimensions in this population. However, there are many barriers including geographical distance which prevent most adolescents from receiving an effective treatment for chronic pain. The present study aimed to investigate the effect of a smartphone-based pain management application compared with face-to-face pain management program and wait-list control on the pain intensity and quality-of-life dimensions in adolescents with chronic pain.

METHODS

This study used a cluster double-blinded randomized parallel-group design with school as the unit of randomization. Participants included were 192 adolescents with chronic pain. The questionnaires (pain intensity and quality of life measuring physical, emotional, social, and school dimensions) were completed at the baseline, immediately at the end of pain management program and three months after the end of the program.

RESULTS

Repeated measures ANOVAs with adjustment for clustering effect showed that there were significant main effects of time on ratings of pain intensity (p < 0.01), physical (p < 0.005), emotional (p < 0.008), social (p < 0.001), and school (p < 0.005) dimensions of quality of life. There was also a significant main effect of group on ratings of emotional (p < 0.001), social (p < 0.009), and school (p < 0.002) dimensions. The interaction of group × time for emotional (p < 0.004), social (p < 0.001), and school (p < 0.005) dimensions of quality of life was statistically significant.

DISCUSSION

The findings suggest that smartphone-based pain management program, which is a highly accessible and cost-effective intervention, may provide benefits similar to a face-to-face intervention and shows promise for being effective on emotional, social, and school dimensions of quality of life in adolescents with different types of chronic pain. The study was registered within the Iranian Registry of Clinical Trials (IRCT20180808040744N2).

Cluster randomised trials of prescribing policy: an ethical approach to generating drug safety evidence? A discussion of the ethical application of a new research method

For most chronic medical conditions, multiple medications are available and prescribers often have limited evidence about which therapy is likely to be the most effective and safe for an individual patient. As many patients are exposed every day to medicines that may be less effective than available alternatives, this is of public health importance. Cluster randomised trials of prescribing policy offer an opportunity to rapidly obtain evidence of comparative effectiveness and safety. These trials can pose a low risk to patients and cause minimal disruption to usual care. Despite the potential scientific value of this approach, there remain valid concerns about consent, medication switching and the use of routinely collected data in research. We discuss these concerns with reference to an ongoing pilot study (Evaluating Diuretics in Normal Care (EVIDENCE) - a cluster randomised evaluation of hypertension prescribing policy, ISRCTN 46635087, registered 11 August 2017).

A stochastic second-order generalized estimating equations approach for estimating association parameters

Design and analysis of cluster randomized trials must take into account the intraclass correlation coefficient (ICC), which quantifies the correlation among outcomes from the same cluster. Second-order generalized estimating equations (GEE2) provides a statistically robust way in estimating this quantity and other association parameters. However, GEE2 becomes computationally infeasible as cluster sizes grow. This paper proposes a stochastic variant to fitting GEE2 which alleviates reliance on parameter starting values and provides substantially faster speeds and higher convergence rates than the widely used deterministic Newton-Raphson method. We also propose new estimators for the ICC which account for informative missing outcome data through the use of GEE2, for which we incorporate a "second-order" inverse probability weighting scheme and "second-order" doubly robust (DR) estimating equations that guard against partial model misspecification. Our proposed methods are evaluated through simulations and applied to data from a cluster randomized trial in Bangladesh evaluating the effect of different marketing interventions on the use of hygienic latrines.

Improving the Youth HIV Prevention and Care Cascades: Innovative Designs in the Adolescent Trials Network for HIV/AIDS Interventions

Dramatic decreases in HIV transmission are achievable with currently available biomedical and behavioral interventions, including antiretroviral therapy and pre-exposure prophylaxis. However, such decreases have not yet been realized among adolescents and young adults. The Adolescent Medicine Trials Network (ATN) for HIV/AIDS interventions is dedicated to research addressing the needs of youth at high risk for HIV acquisition as well as youth living with HIV. This article provides an overview of an array of efficient and effective designs across the translational spectrum that are utilized within the ATN. These designs maximize methodological rigor and real-world applicability of findings while minimizing resource use. Implementation science and cost-effectiveness methods are included. Utilizing protocol examples, we demonstrate the feasibility of such designs to balance rigor and relevance to shorten the science-to-practice gap and improve the youth HIV prevention and care continua.

Baseball Pitchers' Perceived Effort Does Not Match Actual Measured Effort During a Structured Long-Toss Throwing Program

BACKGROUND

During rehabilitation throwing programs, baseball players are commonly asked to throw at reduced levels of effort (ie, 50% effort, 75% effort, etc) to moderate stress to healing tissues. It is currently unknown how changes in players' perceived exertion compares with changes in actual exertion during structured long-toss programs.

PURPOSE

To determine whether decreased effort correlates with decreased throwing metrics, whether metrics decrease proportionally with reductions in perceived effort, and to quantify intrathrower variability.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Sixty male high school and collegiate baseball pitchers participated in a structured throwing program. A motusBASEBALL sleeve was worn by all players, which measured elbow varus torque, arm velocity, arm slot, and shoulder rotation. Ball velocity was measured with a radar gun. Each pitcher threw 5 throws a distance of 120 ft with 3 efforts: maximum effort, 75% effort, and 50% effort. Throwing metrics were compared among the 3 levels of effort to see if each 25% decrease resulted in proportional decreases in elbow varus torque and ball velocity. Intrathrower variability was determined for each throwing metric at each degree of effort.

RESULTS

All throwing metrics decreased as players decreased their perceived effort (P < .001). However, these observed decreases were much smaller in magnitude than the decreases in perceived effort. During the 75% effort throws, elbow varus torque was only reduced to 93% of maximum and velocity dropped to 86% of maximum. Similarly, for the 50% effort throws, elbow varus torque remained 87% of max effort torque, while velocity remained 78% of max. Intrathrower reliability was considered excellent for most metrics (intraclass correlation coefficient, >0.75).

CONCLUSION

For every 25% decrease in perceived effort, elbow varus torque only decreased 7% and velocity only decreased 11%. Thus, when players throw at what they perceive to be reduced effort, their actual throwing metrics do not decrease at the same rate as their perceived exertion.

CLINICAL RELEVANCE

Measured effort decreased with decreasing perceived effort, but these were not proportional. This has significant implications for physical therapists, physicians, trainers, coaches, and athletes to understand and monitor elbow stress during the rehabilitation process.

Intervention in time-processing ability, daily time management and autonomy in children with intellectual disabilities aged 10-17 years - A cluster randomised trial

BACKGROUND/AIM

Difficulties with management of time are frequently observed in children and youth with intellectual disabilities (IDs). The aim of this study was to evaluate a new intervention programme 'My Time' to improve time-processing ability (TPA) in children with IDs aged 10-17 years (n = 61).

METHODS

Cluster randomised and waiting-list control group design was used. Data collection included the Kit for assessment of TPA, the Time-Parent scale and a self-rating of autonomy to assess occupational performance in daily life. The method was implemented over an 8-week period. Effect size (ES) was calculated and an analysis of covariance on the individual level and a two-stage process on the cluster level.

RESULTS

The estimated mean improvement in the KaTid-Child score from baseline (t1) to t2 was significantly higher in the intervention group compared to the waiting-list group, ES Cohen's d = 0.64.

CONCLUSION

The results present first evidence of the effectiveness of a new occupational therapy intervention programme ('My Time') to facilitate TPA in children with mild to moderate IDs. Children with IDs aged 10-17 years could improve their TPA at a measurable pace when given intervention. The method could complement interventions using time-assistive devices. Children with IDs should be identified to guide intervention. Further research is necessary to establish whether using the intervention programme can facilitate the development of TPA in younger children.

Protocol for a cluster randomised controlled trial evaluating a parenting with home visitation programme to prevent physical and emotional abuse of children in Indonesia: the Families First Programme

INTRODUCTION

Every year, up to 1 billion children are victims of violence worldwide. Most child abuse takes place in the context of punishment. The Families First Programme, an adaptation of the Positive Discipline in Everyday Parenting Programme to the West Java context, is a parenting support programme anchored on children's rights that gives parents guidance on child development, parenting and positive discipline practices. This trial will evaluate the effectiveness of the Families First Programme compared with a waitlist control group.

METHODS AND ANALYSIS

This is a pragmatic, parallel-group, stratified, cluster-randomised controlled trial. Twenty rural and urban villages in the Cianjur District, Indonesia, involving 720 caregivers of children up to 7 years of age, will be randomised. Villages will receive either a parenting programme consisting of 10 group sessions and four home visits over 3 months and standard community health and social services or just the latter. After completion of the trial period, the programme will be offered to those in the delayed group. Outcome data will be collected before randomisation (baseline), immediately postintervention (3 months postrandomisation) and 6 months later (9 months postrandomisation). The primary outcome will be frequency of physical and emotional punishment as measured by a weighted sum from three self-report items. Primary outcome analysis will use Poisson regression with generalised estimating equations and assess the interaction between intervention and time over baseline and 3 and 9 months postrandomisation assessments. Concurrent process evaluation will be conducted to assess programme satisfaction and facilitators and barriers to the implementation of the programme generalisable to other settings.

ETHICS AND DISSEMINATION

Ethics approval was obtained from McGill University and Universitas Katolik Indonesia Atma Jaya. Results will be published in peer-reviewed journals and presented at scientific conferences and events for decision-makers, including in the participating communities.

TRIAL REGISTRATION NUMBER

NCT03374761.

Ethical issues in pragmatic randomized controlled trials: a review of the recent literature identifies gaps in ethical argumentation

BACKGROUND

Pragmatic randomized controlled trials (RCTs) are designed to evaluate the effectiveness of interventions in real-world clinical conditions. However, these studies raise ethical issues for researchers and regulators. Our objective is to identify a list of key ethical issues in pragmatic RCTs and highlight gaps in the ethics literature.

METHODS

We conducted a scoping review of articles addressing ethical aspects of pragmatic RCTs. After applying the search strategy and eligibility criteria, 36 articles were included and reviewed using content analysis.

RESULTS

Our review identified four major themes: 1) the research-practice distinction; 2) the need for consent; 3) elements that must be disclosed in the consent process; and 4) appropriate oversight by research ethics committees. 1) Most authors reject the need for a research-practice distinction in pragmatic RCTs. They argue that the distinction rests on the presumptions that research participation offers patients less benefit and greater risk than clinical practice, but neither is true in the case of pragmatic RCTs. 2) Most authors further conclude that pragmatic RCTs may proceed without informed consent or with simplified consent procedures when risks are low and consent is infeasible. 3) Authors who endorse the need for consent assert that information need only be disclosed when research participation poses incremental risks compared to clinical practice. Authors disagree as to whether randomization must be disclosed. 4) Finally, all authors view regulatory oversight as burdensome and a practical impediment to the conduct of pragmatic RCTs, and argue that oversight procedures ought to be streamlined when risks to participants are low.

CONCLUSION

The current ethical discussion is framed by the assumption that the function of research oversight is to protect participants from risk. As pragmatic RCTs commonly involve usual care interventions, the risks may be minimal. This leads many to reject the research-practice distinction and question the need for informed consent. But the function of oversight should be understood broadly as protecting the liberty and welfare interest of participants and promoting public trust in research. This understanding, we suggest, will focus discussion on questions about appropriate ethical review for pragmatic RCTs.

Minimum number of clusters and comparison of analysis methods for cross sectional stepped wedge cluster randomised trials with binary outcomes: A simulation study

BACKGROUND

Stepped wedge cluster randomised trials frequently involve a relatively small number of clusters. The most common frameworks used to analyse data from these types of trials are generalised estimating equations and generalised linear mixed models. A topic of much research into these methods has been their application to cluster randomised trial data and, in particular, the number of clusters required to make reasonable inferences about the intervention effect. However, for stepped wedge trials, which have been claimed by many researchers to have a statistical power advantage over the parallel cluster randomised trial, the minimum number of clusters required has not been investigated.

METHODS

We conducted a simulation study where we considered the most commonly used methods suggested in the literature to analyse cross-sectional stepped wedge cluster randomised trial data. We compared the per cent bias, the type I error rate and power of these methods in a stepped wedge trial setting with a binary outcome, where there are few clusters available and when the appropriate adjustment for a time trend is made, which by design may be confounding the intervention effect.

RESULTS

We found that the generalised linear mixed modelling approach is the most consistent when few clusters are available. We also found that none of the common analysis methods for stepped wedge trials were both unbiased and maintained a 5% type I error rate when there were only three clusters.

CONCLUSIONS

Of the commonly used analysis approaches, we recommend the generalised linear mixed model for small stepped wedge trials with binary outcomes. We also suggest that in a stepped wedge design with three steps, at least two clusters be randomised at each step, to ensure that the intervention effect estimator maintains the nominal 5% significance level and is also reasonably unbiased.

Using Getting To Outcomes to facilitate the use of an evidence-based practice in VA homeless programs: a cluster-randomized trial of an implementation support strategy

BACKGROUND

Incorporating evidence-based integrated treatment for dual disorders into typical care settings has been challenging, especially among those serving Veterans who are homeless. This paper presents an evaluation of an effort to incorporate an evidence-based, dual disorder treatment called Maintaining Independence and Sobriety Through Systems Integration, Outreach, and Networking-Veterans Edition (MISSION-Vet) into case management teams serving Veterans who are homeless, using an implementation strategy called Getting To Outcomes (GTO).

METHODS

This Hybrid Type III, cluster-randomized controlled trial assessed the impact of GTO over and above MISSION-Vet Implementation as Usual (IU). Both conditions received standard MISSION-Vet training and manuals. The GTO group received an implementation manual, training, technical assistance, and data feedback. The study occurred in teams at three large VA Medical Centers over 2 years. Within each team, existing sub-teams (case managers and Veterans they serve) were the clusters randomly assigned. The trial assessed MISSION-Vet services delivered and collected via administrative data and implementation barriers and facilitators, via semi-structured interview.

RESULTS

No case managers in the IU group initiated MISSION-Vet while 68% in the GTO group did. Seven percent of Veterans with case managers in the GTO group received at least one MISSION-Vet session. Most case managers appreciated the MISSION-Vet materials and felt the GTO planning meetings supported using MISSION-Vet. Case manager interviews also showed that MISSION-Vet could be confusing; there was little involvement from leadership after their initial agreement to participate; the data feedback system had a number of difficulties; and case managers did not have the resources to implement all aspects of MISSION-Vet.

CONCLUSIONS

This project shows that GTO-like support can help launch new practices but that multiple implementation facilitators are needed for successful execution of a complex evidence-based program like MISSION-Vet.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01430741.

Intraclass correlation values for adolescent health outcomes in secondary schools in 21 European countries

BACKGROUND

Cluster randomised controlled trials (CRCTs) are increasingly used to evaluate the effectiveness of interventions for improving health. A key feature of CRCTs is that individuals in clusters are often more alike than individuals in different clusters, irrespective of treatment. This similarity within clusters needs to be taken into account when planning CRCTs to obtain adequate sample sizes, and when analysing clustered data to obtain correct estimates.

METHODS

Nationally representative data from 15 to 16 year olds were analysed, from 21 of the 35 countries that participated in the 2007 European School Survey Project on Alcohol and Other Drugs. Within country school level intra-class correlation coefficients (ICCs) were calculated for substance use (self-reported alcohol use, regular alcohol use, binge drinking, any smoking, regular smoking, and illicit drug use) and psychosocial health (depressive mood and self-esteem). Unadjusted and adjusted ICCs are presented. ICCs are adjusted for student sex and socioeconomic status.

RESULTS

ICCs ranged from 0.01 to 0.21, with the highest (0.21) reported for regular smoking. Within country school level ICCs varied substantially across health outcomes, and among countries for the same health outcomes. Estimated ICCs were consistently higher for substance use (range 0.01-0.21), than for psychosocial health (range 0.01-0.07). Within country ICCs for health outcomes varied by changes in the measurement of particular health outcomes, for example the ICCs for regular smoking (range 0.06-0.21) were higher than those for having smoked at all in the last month (range 0.03-0.17).

CONCLUSIONS

For school level ICCs to be effectively utilised in informing sample size requirements for CRCTs and adjusting estimates from meta-analyses, the school level ICCs need to be both country and outcome specific.

Comparison of subject-specific and population averaged models for count data from cluster-unit intervention trials

Maximum likelihood estimation techniques for subject-specific (SS) generalized linear mixed models and generalized estimating equations for marginal or population-averaged (PA) models are often used for the analysis of cluster-unit intervention trials. Although both classes of procedures account for the presence of within-cluster correlations, the interpretations of fixed effects including intervention effect parameters differ in SS and PA models. Furthermore, closed-form mathematical expressions relating SS and PA parameters from the two respective approaches are generally lacking. This paper investigates the special case of correlated Poisson responses where, for a log-linear model with normal random effects, exact relationships are available. Equivalent PA model representations of two SS models commonly used in the analysis of nested cross-sectional cluster trials with count data are derived. The mathematical results are illustrated with count data from a large non-randomized cluster trial to reduce underage drinking. Knowledge of relationships among parameters in the respective mean and covariance models is essential to understanding empirical comparisons of the two approaches.

Meta-analyses involving cluster randomization trials: a review of published literature in health care

Throughout the 1980s and 1990s cluster randomization trials have been increasingly used to evaluate effectivenessof health care intervention. Such trials have raised several methodologic challenges in analysis. Meta-analyses involving cluster randomization trials are becoming common in the area of health care intervention. However, as yet there has been no empirical evidence of current practice in the meta-analyses. Thus a review was performed to identify and examine synthesis approaches of meta-analyses involving cluster randomization trials in the published literature. Electronic databases were searched for meta-analyses involving cluster randomization trials from the earliest date available to 2000. Once a meta-analysis was identified, papers on the relevant cluster randomization trials included were also requested. Each of the original papers of cluster randomization trials included was examined for its randomized design and unit, and adjustment for clustering effect in analysis. Each of the selected meta-analyses was then evaluated as to its synthesis concerning clustering effect. In total, 25 eligible meta-analyses were reviewed. Of these, 15 meta-analyses reported simple conventional methods of the fixed-effect model as method of analysis, while six did not incorporate the cluster randomization trial results in the synthesis methods but described the trial results individually. Three meta-analyses attempted to account for the clustering effect in the synthesis methods but approaches were in arbitrary. Fifteen meta-analyses included more than one cluster randomization trial, each of which included cluster randomization trials with a mixture of randomized designs and units, and units of analysis. These mixture situations might increase heterogeneity, but have not been considered in any meta-analysis. Some methods dealing with a binary outcome for some specific situations have been discussed. In conclusion, some difficulties in the quantitative synthesis procedures were found in the meta-analyses involving cluster randomization trials. Recommendations in the applications of approaches to some specific situations in a binary outcome variable have also been provided. There are still, however, several methodologic issues of the meta-analyses involving cluster randomization trials that need to be investigated further.

Twin Birth Study: 2-year neurodevelopmental follow-up of the randomized trial of planned cesarean or planned vaginal delivery for twin pregnancy

BACKGROUND

The Twin Birth Study randomized women with uncomplicated pregnancies, between 32(0/7)-38(6/7) weeks' gestation where the first twin was in cephalic presentation, to a policy of either a planned cesarean or planned vaginal delivery. The primary analysis showed that planned cesarean delivery did not increase or decrease the risk of fetal/neonatal death or serious neonatal morbidity as compared with planned vaginal delivery.

OBJECTIVE

This study presents the secondary outcome of death or neurodevelopmental delay at 2 years of age.

STUDY DESIGN

A total of 4603 children from the initial cohort of 5565 fetuses/infants (83%) contributed to the outcome of death or neurodevelopmental delay. Surviving children were screened using the Ages and Stages Questionnaire with abnormal scores validated by a clinical neurodevelopmental assessment. The effect of planned cesarean vs planned vaginal delivery on death or neurodevelopmental delay was quantified using a logistic model to control for stratification variables and using generalized estimating equations to account for the nonindependence of twin births.

RESULTS

Baseline maternal, pregnancy, and infant characteristics were similar. Mean age at assessment was 26 months. There was no significant difference in the outcome of death or neurodevelopmental delay: 5.99% in the planned cesarean vs 5.83% in the planned vaginal delivery group (odds ratio, 1.04; 95% confidence interval, 0.77-1.41; P = .79).

CONCLUSION

A policy of planned cesarean delivery provides no benefit to children at 2 years of age compared with a policy of planned vaginal delivery in uncomplicated twin pregnancies between 32(0/7)-38(6/7)weeks' gestation where the first twin is in cephalic presentation.

Logistic, ethical, and political dimensions of stepped wedge trials: critical review and case studies

Background

Three arguments are usually invoked in favour of stepped wedge cluster randomised controlled trials: the logistic convenience of implementing an intervention in phases, the ethical benefit of providing the intervention to all clusters, and the potential to enhance the social acceptability of cluster randomised controlled trials. Are these alleged benefits real? We explored the logistic, ethical, and political dimensions of stepped wedge trials using case studies of six recent evaluations.

Methods

We identified completed or ongoing stepped wedge evaluations using two systematic reviews. We then purposively selected six with a focus on public health in high, middle, and low-income settings. We interviewed their authors about the logistic, ethical, and social issues faced by their teams. Two authors reviewed interview transcripts, identified emerging issues through qualitative thematic analysis, reflected upon them in the context of the literature, and invited all participants to co-author the manuscript.

Results

Our analysis raises three main points. First, the phased implementation of interventions can alleviate problems linked to simultaneous roll-out, but also brings new challenges. Issues to consider include the feasibility of organising intervention activities according to a randomised sequence, estimating time lags in implementation and effects, and accommodating policy changes during the trial period. Second, stepped wedge trials, like parallel cluster trials, require equipoise: without it, randomising participants to a control condition, even for a short time, remains problematic. In stepped wedge trials, equipoise is likely to lie in the degree of effect, effectiveness in a specific operational milieu, and the balance of benefit and harm, including the social value of better evaluation. Third, the strongest arguments for a stepped wedge design are logistic and political rather than ethical. The design is advantageous when simultaneous roll-out is impractical and when it increases the acceptability of using counterfactuals.

Conclusions

The logistic convenience of phased implementation is context-dependent, and may be vitiated by the additional requirements of phasing. The potential for stepped wedge trials to enhance the social acceptability of cluster randomised trials is real, but their ethical legitimacy still rests on demonstrating equipoise and its configuration for each research question and setting.

Improving end-of-life care in acute geriatric hospital wards using the Care Programme for the Last Days of Life: study protocol for a phase 3 cluster randomized controlled trial

Background

The Care Programme for the Last Days of Life has been developed to improve the quality of end-of-life care in acute geriatric hospital wards. The programme is based on existing end-of-life care programmes but modeled to the acute geriatric care setting. There is a lack of evidence of the effectiveness of end-of-life care programmes and the effects that may be achieved in patients dying in an acute geriatric hospital setting are unknown. The aim of this paper is to describe the research protocol of a cluster randomized controlled trial to evaluate the effects of the Care Programme for the Last Days of Life.

Methods and design

A cluster randomized controlled trial will be conducted. Ten hospitals with one or more acute geriatric wards will conduct a one-year baseline assessment during which care will be provided as usual. For each patient dying in the ward, a questionnaire will be filled in by a nurse, a physician and a family carer. At the end of the baseline assessment hospitals will be randomized to receive intervention (implementation of the Care Programme) or no intervention. Subsequently, the Care Programme will be implemented in the intervention hospitals over a six-month period. A one-year post-intervention assessment will be performed immediately after the baseline assessment in the control hospitals and after the implementation period in the intervention hospitals. Primary outcomes are symptom frequency and symptom burden of patients in the last 48 hours of life.

Discussion

This will be the first cluster randomized controlled trial to evaluate the effect of the Care Programme for the Last Days of Life for the acute geriatric hospital setting. The results will enable us to evaluate whether implementation of the Care Programme has positive effects on end-of-life care during the last days of life in this patient population and which components of the Care Programme contribute to improving the quality of end-of-life care.

Trial registration

ClinicalTrials.gov Identifier: NCT01890239. Registered June 24th, 2013.

A Telehealth Intervention Using Nintendo Wii Fit Balance Boards and iPads to Improve Walking in Older Adults With Lower Limb Amputation (Wii.n.Walk): Study Protocol for a Randomized Controlled Trial

Background

The number of older adults living with lower limb amputation (LLA) who require rehabilitation for improving their walking capacity and mobility is growing. Existing rehabilitation practices frequently fail to meet this demand. Nintendo Wii Fit may be a valuable tool to enable rehabilitation interventions. Based on pilot studies, we have developed “Wii.n.Walk”, an in-home telehealth Wii Fit intervention targeted to improve walking capacity in older adults with LLA.

Objective

The objective of this study is to determine whether the Wii.n.Walk intervention enhances walking capacity compared to an attention control group.

Methods

This project is a multi-site (Vancouver BC, London ON), parallel, evaluator-blind randomized controlled trial. Participants include community-dwelling older adults over the age of 50 years with unilateral transtibial or transfemoral amputation. Participants will be stratified by site and block randomized in triplets to either the Wii.n.Walk intervention or an attention control group employing the Wii Big Brain cognitive software. This trial will include both supervised and unsupervised phases. During the supervised phase, both groups will receive 40-minute sessions of supervised group training three times per week for a duration of 4 weeks. Participants will complete the first week of the intervention in groups of three at their local rehabilitation center with a trainer. The remaining 3 weeks will take place at participants’ homes using remote supervision by the trainer using Apple iPad technology. At the end of 4 weeks, the supervised period will end and the unsupervised period will begin. Participants will retain the Wii console and be encouraged to continue using the program for an additional 4 weeks’ duration. The primary outcome measure will be the “Two-Minute Walk Test” to measure walking capacity. Outcome measures will be evaluated for all participants at baseline, after the end of both the supervised and unsupervised phases, and after 1-year follow up.

Results

Study staff have been hired and trained at both sites and recruitment is currently underway. No participants have been enrolled yet.

Conclusions

Wii.n.Walk is a promising in-home telehealth intervention that may have useful applications for older adults with LLA who are discharged from rehabilitation or live in remote areas having limited or no access to existing rehabilitation programs.

Trial Registration

Clinicaltrial.gov NCT01942798; http://clinicaltrials.gov/ct2/show/NCT01942798 (Archived by WebCite at http://www.webcitation.org/6V0w8baKP).

A cluster randomized clinical trial comparing functional capacity evaluation and functional interviewing as components of occupational rehabilitation programs

PURPOSE

Functional capacity evaluations (FCE) are used to identify work abilities and are commonly integrated into rehabilitation programs. We studied whether integrating FCE into rehabilitation leads to better outcomes for injured workers.

METHODS

A cluster randomised controlled trial was conducted at a workers' compensation rehabilitation facility (registration ISRCTN61284905). Clinicians were randomised into 2 groups: 1 group used FCE while another conducted semi-structured functional interviews. Outcomes included recommendations following assessment, rehabilitation program outcomes including functional work levels and pain intensity, as well as compensation outcomes at 1, 3, and 6 months after assessment. Analysis included Mann-Whitney U, Chi square and t tests.

RESULTS

Subjects included 225 claimants of whom 105 were tested with FCE. Subjects were predominantly employed (84 %) males (63 %) with sub-acute musculoskeletal conditions (median duration 67 days). Claimants undergoing FCE had ~15 % higher average functional work levels recommended at time of assessment (Mann-Whitney U = 4,391.0, p < 0.001) but differences at other follow-up times were smaller (0-8 %), in favour of functional interviewing, and not statistically significant. Clinically important improvement during rehabilitation in functional work level (0.9/4, SRM = 0.94), pain intensity (2.0/10, SRM = 0.88) and self-reported disability (21.8/100, SRM = 1.45) were only observed in those undergoing the functional interview.

CONCLUSIONS

Performance-based FCE integrated into occupational rehabilitation appears to lead to higher baseline functional work levels compared to a semi-structured functional interview, but not improved RTW rates or functional work levels at follow-up. Functional interviewing has potential for efficiency gains and higher likelihood of clinically important improvement following rehabilitation, however further research is needed.

Implementing comprehensive prevention of mother-to-child transmission and HIV prevention for South African couples: study protocol for a randomized controlled trial

BACKGROUND

In rural South Africa, only two-thirds of HIV-positive pregnant women seeking antenatal care at community health centers took full advantage of 'prevention of mother-to-child transmission' (PMTCT) services in 2010. Studies generally support male involvement to promote PMTCT, but the nature and impact of that involvement is unclear and untested. Additionally, stigma, disclosure and intimate partner violence pose significant barriers to PMTCT uptake and retention in care, suggesting that male involvement may be 'necessary, but not sufficient' to reduce infant HIV incidence. This study expands on a successful United States President's Emergency Plan for AIDS Relief (PEPFAR)-supported PMTCT couples intervention pilot study conducted in the Mpumalanga province, targeting HIV-positive pregnant women and their partners, the primary objective being to determine whether male partner involvement plus a behavioral intervention will significantly reduce infant HIV incidence.

METHODS/DESIGN

The study follows a cluster randomized controlled design enrolling two cohorts of HIV-positive pregnant women recruited from 12 randomly assigned Community Health Centers (CHC) (six experimental, six control). The two cohorts will consist of women attending without their male partners (n = 720) and women attending with their male partners (n = 720 couples), in order to determine whether the influence of male participation itself, or combined with a behavioral PMTCT intervention, can significantly reduce infant HIV infection ante-, peri- and postnatally.

DISCUSSION

It is our intention to significantly increase PMTCT participation from current levels (69%) in the Mpumalanga province to between 90 and 95% through engaging women and couples in a controlled, six session ante- and postnatal risk-reducing and PMTCT promotion intervention addressing barriers to PMTCT (such as stigma, disclosure, intimate partner violence, communication, infant feeding practices and safer conception) that prevent women and men from utilizing treatment opportunities available to them and their infants. Based upon the encouraging preliminary results from our pilot study, successful CHC adoption of the program could have major public health policy implications for containing the epidemic among the most vulnerable populations in rural South Africa: HIV-positive pregnant women and their infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02085356 (registration date: 10 March 2014).

Scientific evidence and research in antimicrobial stewardship

Evaluating the impact of antibiotic stewardship programs is challenging. There is evidence that they are effective in terms of reducing the consumption and cost of antibiotics, although establishing their impact on antimicrobial resistance (beyond restrictive policies in outbreaks caused by specific antimicrobial resistant organisms) and clinical outcomes is more difficult. Proper definitions of exposure and outcome variables, the use of advanced and appropriate statistical analyses and well-designed quasi-experimental studies would more accurately support the conclusions. Cluster randomized trials should be used whenever possible and appropriate, although the limitations of this approach should also be acknowledged. These issues are reviewed in this paper. We conclude that there are good research opportunities in the field of antibiotic stewardship.

Assessing outcomes of a stigma-reduction intervention with venue-based analysis

PURPOSE

A randomized controlled trial with a matched design was conducted during October 2008 and February 2010, aiming at reducing HIV-related stigma in healthcare settings.

METHODS

Forty county hospitals in Fujian and Yunnan provinces of China were matched into pairs and randomized to either an intervention condition or a control condition. Forty-four service providers were randomly selected from each hospital, yielding a sample of 1,760. Intervention outcomes were assessed at baseline, 6 and 12 months based on venue-based pair comparisons. We identified and trained 30 popular opinion leaders in each intervention hospital among service providers to disseminate stigma-reduction messages to their peer providers.

RESULTS

Hospital and participant characteristics were comparable between the intervention and control conditions. Thirteen out of twenty pairs of hospitals showed significant reduction in the stigma outcome measure at the 6-month follow-up assessment. For most hospitals, the intervention effects were maintained at the 12-month follow-up assessment. Among the 13 pair of hospitals, which showed intervention effects at 6 months, eight were in Fujian and five were in Yunnan. The non-significant hospitals at 6 months had more beds than significant hospitals. However, the difference did not reach statistical significance.

CONCLUSIONS

A matched design and venue-based analysis provide more insight in assessing intervention effects for facility-based intervention trials. The identification of venue-based or hospital characteristics that are associated with intervention efficacy provides additional implications for the adaptation and implementation of future interventions.

Sample size considerations in the design of cluster randomized trials of combination HIV prevention

Background Cluster randomized trials have been utilized to evaluate the effectiveness of HIV prevention strategies on reducing incidence. Design of such studies must take into account possible correlation of outcomes within randomized units. Purpose To discuss power and sample size considerations for cluster randomized trials of combination HIV prevention, using an HIV prevention study in Botswana as an illustration. Methods We introduce a new agent-based model to simulate the community-level impact of a combination prevention strategy and investigate how correlation structure within a community affects the coefficient of variation - an essential parameter in designing a cluster randomized trial. Results We construct collections of sexual networks and then propagate HIV on them to simulate the disease epidemic. Increasing level of sexual mixing between intervention and standard-of-care (SOC) communities reduces the difference in cumulative incidence in the two sets of communities. Fifteen clusters per arm and 500 incidence cohort members per community provide 95% power to detect the projected difference in cumulative HIV incidence between SOC and intervention communities (3.93% and 2.34%) at the end of the third study year, using a coefficient of variation 0.25. Although available formulas for calculating sample size for cluster randomized trials can be derived by assuming an exchangeable correlation structure within clusters, we show that deviations from this assumption do not generally affect the validity of such formulas. Limitations We construct sexual networks based on data from Likoma Island, Malawi, and base disease progression on longitudinal estimates from an incidence cohort in Botswana and in Durban as well as a household survey in Mochudi, Botswana. Network data from Botswana and larger sample sizes to estimate rates of disease progression would be useful in assessing the robustness of our model results. Conclusion Epidemic modeling plays a critical role in planning and evaluating interventions for prevention. Simulation studies allow us to take into consideration available information on sexual network characteristics, such as mixing within and between communities as well as coverage levels for different prevention modalities in the combination prevention package.

Detailed statistical analysis plan for the difficult airway management (DIFFICAIR) trial

Background

Preoperative airway assessment in Denmark is based on a non-specific clinical assessment left to the discretion of the responsible anesthesiologist. The DIFFICAIR trial compares the effect of using a systematic and consistent airway assessment versus a non-specific clinical assessment on the frequency of unanticipated difficult airway management.

To prevent outcome bias and selective reporting, we hereby present a detailed statistical analysis plan as an amendment (update) to the previously published protocol for the DIFFICAIR trial.

Method/Design

The DIFFICAIR trial is a stratified, parallel group, cluster (cluster = department) randomized multicenter trial involving 28 departments of anesthesia in Denmark randomized to airway assessment either by the Simplified Airway Risk Index (SARI) or by a usual non-specific assessment. Data from patients’ preoperative airway assessment are registered in the Danish Anesthesia Database. An objective score for intubation grading the severity, that is the severity of the intubations, as well as the frequency of unanticipated difficult intubation, is measured for each group.

Primary outcome measures are the fraction of unanticipated difficult and easy intubations.

The database is programmed so that the registration of the SARI is mandatory for the intervention group but invisible to controls.

Data recruitment was commenced in October 2012 and ended in ultimo December 2013.

Conclusion

We intend to increase the transparency of the data analyses regarding the DIFFICAIR trial by an a priori publication of a statistical analysis plan.

Trial registration

ClinicalTrials.gov: NCT01718561.

A school-based program implemented by community providers previously trained for the prevention of eating and weight-related problems in secondary-school adolescents: the MABIC study protocol

Background

The prevention of eating disorders and disordered eating are increasingly recognized as public health priorities. Challenges in this field included moving from efficacy to effectiveness and developing an integrated approach to the prevention of a broad spectrum of eating and weight-related problems. A previous efficacy trial indicated that a universal disordered eating prevention program, based on the social cognitive model, media literacy educational approach and cognitive dissonance theory, reduced risk factors for disordered eating, but it is unclear whether this program has effects under more real-world conditions. The main aim of this effectiveness trial protocol is to test whether this program has effects when incorporating an integrated approach to prevention and when previously-trained community providers implement the intervention.

Methods/design

The research design involved a multi-center non-randomized controlled trial with baseline, post and 1-year follow-up measures. Six schools from the city of Sabadell (close to Barcelona) participated in the intervention group, and eleven schools from four towns neighboring Sabadell participated in the control group. A total of 174 girls and 180 boys in the intervention group, and 484 girls and 490 boys in the control group were registered in class lists prior to baseline. A total of 18 community providers, secondary-school class tutors, nurses from the Catalan Government’s Health and School Program, and health promotion technicians from Sabadell City Council were trained and delivered the program. Shared risk factors of eating and weight-related problems were assessed as main measures.

Discussion

It will be vital for progress in disordered eating prevention to conduct effectiveness trials, which test whether interventions are effective when delivered by community providers under ecologically valid conditions, as opposed to tightly controlled research trials. The MABIC project will provide new contributions in this transition from efficacy to effectiveness and new data about progress in the integrated approach to prevention. Pending the results, the effectiveness trial meets the effectiveness standards set down by the Society for Prevention Research. This study will provide new evidence to improve and enhance disordered eating prevention programs.

Trial registration

Current Controlled Trials ISRCTN47682626

A randomized trial of planned cesarean or vaginal delivery for twin pregnancy

BACKGROUND

Twin birth is associated with a higher risk of adverse perinatal outcomes than singleton birth. It is unclear whether planned cesarean section results in a lower risk of adverse outcomes than planned vaginal delivery in twin pregnancy.

METHODS

We randomly assigned women between 32 weeks 0 days and 38 weeks 6 days of gestation with twin pregnancy and with the first twin in the cephalic presentation to planned cesarean section or planned vaginal delivery with cesarean only if indicated. Elective delivery was planned between 37 weeks 5 days and 38 weeks 6 days of gestation. The primary outcome was a composite of fetal or neonatal death or serious neonatal morbidity, with the fetus or infant as the unit of analysis for the statistical comparison.

RESULTS

A total of 1398 women (2795 fetuses) were randomly assigned to planned cesarean delivery and 1406 women (2812 fetuses) to planned vaginal delivery. The rate of cesarean delivery was 90.7% in the planned-cesarean-delivery group and 43.8% in the planned-vaginal-delivery group. Women in the planned-cesarean-delivery group delivered earlier than did those in the planned-vaginal-delivery group (mean number of days from randomization to delivery, 12.4 vs. 13.3; P=0.04). There was no significant difference in the composite primary outcome between the planned-cesarean-delivery group and the planned-vaginal-delivery group (2.2% and 1.9%, respectively; odds ratio with planned cesarean delivery, 1.16; 95% confidence interval, 0.77 to 1.74; P=0.49).

CONCLUSIONS

In twin pregnancy between 32 weeks 0 days and 38 weeks 6 days of gestation, with the first twin in the cephalic presentation, planned cesarean delivery did not significantly decrease or increase the risk of fetal or neonatal death or serious neonatal morbidity, as compared with planned vaginal delivery. (Funded by the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00187369; Current Controlled Trials number, ISRCTN74420086.).

Sample size determination for clustered count data

We consider the problem of sample size determination for count data. Such data arise naturally in the context of multicenter (or cluster) randomized clinical trials, where patients are nested within research centers. We consider cluster-specific and population-averaged estimators (maximum likelihood based on generalized mixed-effect regression and generalized estimating equations, respectively) for subject-level and cluster-level randomized designs, respectively. We provide simple expressions for calculating the number of clusters when comparing event rates of two groups in cross-sectional studies. The expressions we derive have closed-form solutions and are based on either between-cluster variation or intercluster correlation for cross-sectional studies. We provide both theoretical and numerical comparisons of our methods with other existing methods. We specifically show that the performance of the proposed method is better for subject-level randomized designs, whereas the comparative performance depends on the rate ratio for the cluster-level randomized designs. We also provide a versatile method for longitudinal studies. Three real data examples illustrate the results.

Prescribing ANtiDepressants Appropriately (PANDA): a cluster randomized controlled trial in primary care

BACKGROUND

Inappropriate use of antidepressants (AD), defined as either continuation in the absence of a proper indication or continuation despite the lack of therapeutic efficacy, applies to approximately half of all long term AD users.

METHODS/DESIGN

We have designed a cluster randomized controlled clinical trial to assess the (cost-) effectiveness of an antidepressant cessation advice in the absence of a proper indication for maintenance treatment with antidepressants in primary care.We will select all patients using antidepressants for over 9 months from 45 general practices. Patients will be diagnosed using the Composite International Diagnostic Interview (CIDI) version 3.0, extended with questions about the psychiatric history and previous treatment strategies. General practices will be randomized to either the intervention or the control group. In case of overtreatment, defined as the absence of a proper indication according to current guidelines, a cessation advice is given to the general practitioner. In the control groups no specific information is given. The primary outcome measure will be the proportion of patients that successfully discontinue their antidepressants at one-year follow-up. Secondary outcomes are dimensional measures of psychopathology and costs.

DISCUSSION

This study protocol provides a detailed overview of the design of the trial. Study results will be of importance for refining current guidelines. If the intervention is effective it can be used in managed care programs.

TRIAL REGISTRATION

NTR2032.

Antimicrobial agent exposure and the emergence and spread of resistant microorganisms: issues associated with study design

Antibiotics are essential agents that have greatly reduced human mortality due to infectious diseases. Their use, and sometimes overuse, have increased over the past several decades in humans, veterinary medicine and agriculture. However, the emergence of resistant pathogens is becoming an increasing problem that could result in the re-emergence of infectious diseases. Antibiotic prescription in human medicine plays a key role in this phenomenon. Under selection pressure, resistance can emerge in the commensal flora of treated individuals and disseminate to others. However, even if the effects of antimicrobial use on resistance is intuitively accepted, scientific rationales are required to convince physicians, legislators and public opinion to adopt appropriate behaviours and policies. With this review, we aim to provide an overview of different epidemiological study designs that are used to study the relationship between antibiotic use and the emergence and spread of resistance, as well as highlight their main strengths and weaknesses.

Prescribing Data in General Practice Demonstration (PDGPD) project--a cluster randomised controlled trial of a quality improvement intervention to achieve better prescribing for chronic heart failure and hypertension

BACKGROUND

Research literature consistently documents that scientifically based therapeutic recommendations are not always followed in the hospital or in the primary care setting. Currently, there is evidence that some general practitioners in Australia are not prescribing appropriately for patients diagnosed with 1) hypertension (HT) and 2) chronic heart failure (CHF). The objectives of this study were to improve general practitioner's drug treatment management of these patients through feedback on their own prescribing and small group discussions with peers and a trained group facilitator. The impact evaluation includes quantitative assessment of prescribing changes at 6, 9, 12 and 18 months after the intervention.

METHODS

A pragmatic multi site cluster RCT began recruiting practices in October 2009 to evaluate the effects of a multi-faceted quality improvement (QI) intervention on prescribing practice among Australian general practitioners (GP) in relation to patients with CHF and HT. General practices were recruited nationally through General Practice Networks across Australia. Participating practices were randomly allocated to one of three groups: two groups received the QI intervention (the prescribing indicator feedback reports and small group discussion) with each group undertaking the clinical topics (CHF and HT) in reverse order to the other. The third group was waitlisted to receive the intervention 6 months later and acted as a "control" for the other two groups.De-identified data on practice, doctor and patient characteristics and their treatment for CHF and HT are extracted at six-monthly intervals before and after the intervention. Post-test comparisons will be conducted between the intervention and control arms using intention to treat analysis and models that account for clustering of practices in a Network and clustering of patients within practices and GPs.

DISCUSSION

This paper describes the study protocol for a project that will contribute to the development of acceptable and sustainable methods to promote QI activities within routine general practice, enhance prescribing practices and improve patient outcomes in the context of CHF and HT.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR), Trial # 320870.

A new dependence parameter approach to improve the design of cluster randomized trials with binary outcomes

BACKGROUND AND PURPOSE

Power and sample size calculations for cluster randomized trials require prediction of the degree of correlation that will be realized among outcomes of participants in the same cluster. This correlation is typically quantified as the intraclass correlation coefficient (ICC), defined as the Pearson correlation between two members of the same cluster or proportion of the total variance attributable to variance between clusters. It is widely known but perhaps not fully appreciated that for binary outcomes, the ICC is a function of outcome prevalence. Hence, the ICC and the outcome prevalence are intrinsically related, making the ICC poorly generalizable across study conditions and between studies with different outcome prevalences.

METHODS

We use a simple parametrization of the ICC that aims to isolate that part of the ICC that measures dependence among responses within a cluster from the outcome prevalence. We incorporate this parametrization into sample size calculations for cluster randomized trials and compare our method to the traditional approach using the ICC.

RESULTS

Our dependence parameter, R, may be less influenced by outcome prevalence and has an intuitive meaning that facilitates interpretation. Estimates of R from previous studies can be obtained using simple statistics. Comparison of methods showed that the traditional ICC approach to sample size determination tends to overpower studies under many scenarios, calling for more clusters than truly required.

LIMITATIONS

The methods are developed for equal-sized clusters, whereas cluster size may vary in practice.

CONCLUSIONS

The dependence parameter R is an alternative measure of dependence among binary outcomes in cluster randomized trials that has a number of advantages over the ICC.

Reconciling research and implementation in micro health insurance experiments in India: study protocol for a randomized controlled trial

BACKGROUND

Microinsurance or Community-Based Health Insurance is a promising healthcare financing mechanism, which is increasingly applied to aid rural poor persons in low-income countries. Robust empirical evidence on the causal relations between Community-Based Health Insurance and healthcare utilisation, financial protection and other areas is scarce and necessary. This paper contains a discussion of the research design of three Cluster Randomised Controlled Trials in India to measure the impact of Community-Based Health Insurance on several outcomes.

METHODS/DESIGN

Each trial sets up a Community-Based Health Insurance scheme among a group of micro-finance affiliate families. Villages are grouped into clusters which are congruous with pre-existing social groupings. These clusters are randomly assigned to one of three waves of implementation, ensuring the entire population is offered Community-Based Health Insurance by the end of the experiment. Each wave of treatment is preceded by a round of mixed methods evaluation, with quantitative, qualitative and spatial evidence on impact collected. Improving upon practices in published Cluster Randomised Controlled Trial literature, we detail how research design decisions have ensured that both the households offered insurance and the implementers of the Community-Based Health Insurance scheme operate in an environment replicating a non-experimental implementation.

DISCUSSION

When a Cluster Randomised Controlled Trial involves randomizing within a community, generating adequate and valid conclusions requires that the research design must be made congruous with social structures within the target population, to ensure that such trials are conducted in an implementing environment which is a suitable analogue to that of a non-experimental implementing environment.