Variations in stepped-wedge cluster randomized trial design: Insights from the Patient-Centered Care Transitions in Heart Failure trial

Adherence to key recommendations for design and analysis of stepped-wedge cluster randomized trials: A review of trials published 2016-2022

BACKGROUND/AIMS

The stepped-wedge cluster randomized trial (SW-CRT), in which clusters are randomized to a time at which they will transition to the intervention condition - rather than a trial arm - is a relatively new design. SW-CRTs have additional design and analytical considerations compared to conventional parallel arm trials. To inform future methodological development, including guidance for trialists and the selection of parameters for statistical simulation studies, we conducted a review of recently published SW-CRTs. Specific objectives were to describe (1) the types of designs used in practice, (2) adherence to key requirements for statistical analysis, and (3) practices around covariate adjustment. We also examined changes in adherence over time and by journal impact factor.

METHODS

We used electronic searches to identify primary reports of SW-CRTs published 2016-2022. Two reviewers extracted information from each trial report and its protocol, if available, and resolved disagreements through discussion.

RESULTS

We identified 160 eligible trials, randomizing a median (Q1-Q3) of 11 (8-18) clusters to 5 (4-7) sequences. The majority (122, 76%) were cross-sectional (almost all with continuous recruitment), 23 (14%) were closed cohorts and 15 (9%) open cohorts. Many trials had complex design features such as multiple or multivariate primary outcomes (50, 31%) or time-dependent repeated measures (27, 22%). The most common type of primary outcome was binary (51%); continuous outcomes were less common (26%). The most frequently used method of analysis was a generalized linear mixed model (112, 70%); generalized estimating equations were used less frequently (12, 8%). Among 142 trials with fewer than 40 clusters, only 9 (6%) reported using methods appropriate for a small number of clusters. Statistical analyses clearly adjusted for time effects in 119 (74%), for within-cluster correlations in 132 (83%), and for distinct between-period correlations in 13 (8%). Covariates were included in the primary analysis of the primary outcome in 82 (51%) and were most often individual-level covariates; however, clear and complete pre-specification of covariates was uncommon. Adherence to some key methodological requirements (adjusting for time effects, accounting for within-period correlation) was higher among trials published in higher versus lower impact factor journals. Substantial improvements over time were not observed although a slight improvement was observed in the proportion accounting for a distinct between-period correlation.

CONCLUSIONS

Future methods development should prioritize methods for SW-CRTs with binary or time-to-event outcomes, small numbers of clusters, continuous recruitment designs, multivariate outcomes, or time-dependent repeated measures. Trialists, journal editors, and peer reviewers should be aware that SW-CRTs have additional methodological requirements over parallel arm designs including the need to account for period effects as well as complex intracluster correlations.

The staircase cluster randomised trial design: A pragmatic alternative to the stepped wedge

This article introduces the 'staircase' design, derived from the zigzag pattern of steps along the diagonal of a stepped wedge design schematic where clusters switch from control to intervention conditions. Unlike a complete stepped wedge design where all participating clusters must collect and provide data for the entire trial duration, clusters in a staircase design are only required to be involved and collect data for a limited number of pre- and post-switch periods. This could alleviate some of the burden on participating clusters, encouraging involvement in the trial and reducing the likelihood of attrition. Staircase designs are already being implemented, although in the absence of a dedicated methodology, approaches to sample size and power calculations have been inconsistent. We provide expressions for the variance of the treatment effect estimator when a linear mixed model for an outcome is assumed for the analysis of staircase designs in order to enable appropriate sample size and power calculations. These include explicit variance expressions for basic staircase designs with one pre- and one post-switch measurement period. We show how the variance of the treatment effect estimator is related to key design parameters and demonstrate power calculations for examples based on a real trial.

Bridging Treatment Implementation Gaps in Patients With Heart Failure: JACC Focus Seminar 2/3

Heart failure (HF) is a leading cause of death and disability in older adults. Despite decades of high-quality evidence to support their use, guideline-directed medical therapies (GDMTs) that reduce death and disease burden in HF have been suboptimally implemented. Approaches to closing care gaps have focused largely on strategies proven to be ineffective, whilst effective interventions shown to improve GDMT uptake have not been instituted. This review synthesizes implementation interventions that increase the uptake of GDMT, discusses barriers and facilitators of implementation, summarizes conceptual frameworks in implementation science that could improve knowledge uptake, and offers suggestions for trial design that could better facilitate end-of-trial implementation. We propose an evidence-to-care conceptual model that could foster the simultaneous generation of evidence and long-term implementation. By adopting principles of implementation science, policymakers, researchers, and clinicians can help reduce the burden of HF on patients and health care systems worldwide.

The impact of iterative removal of low-information cluster-period cells from a stepped wedge design

BACKGROUND

Standard stepped wedge trials, where clusters switch from the control to the intervention condition in a staggered manner, can be costly and burdensome. Recent work has shown that the amount of information contributed by each cluster in each period differs, with some cluster-periods contributing a relatively small amount of information. We investigate the patterns of the information content of cluster-period cells upon iterative removal of low-information cells, assuming a model for continuous outcomes with constant cluster-period size, categorical time period effects, and exchangeable and discrete-time decay intracluster correlation structures.

METHODS

We sequentially remove pairs of "centrosymmetric" cluster-period cells from an initially complete stepped wedge design which contribute the least amount of information to the estimation of the treatment effect. At each iteration, we update the information content of the remaining cells, determine the pair of cells with the lowest information content, and repeat this process until the treatment effect cannot be estimated.

RESULTS

We demonstrate that as more cells are removed, more information is concentrated in the cells near the time of the treatment switch, and in "hot-spots" in the corners of the design. For the exchangeable correlation structure, removing the cells from these hot-spots leads to a marked reduction in study precision and power, however the impact of this is lessened for the discrete-time decay structure.

CONCLUSIONS

Removing cluster-period cells distant from the time of the treatment switch may not lead to large reductions in precision or power, implying that certain incomplete designs may be almost as powerful as complete designs.

The batched stepped wedge design: A design robust to delays in cluster recruitment

Stepped wedge designs are an increasingly popular variant of longitudinal cluster randomized trial designs, and roll out interventions across clusters in a randomized, but step-wise fashion. In the standard stepped wedge design, assumptions regarding the effect of time on outcomes may require that all clusters start and end trial participation at the same time. This would require ethics approvals and data collection procedures to be in place in all clusters before a stepped wedge trial can start in any cluster. Hence, although stepped wedge designs are useful for testing the impacts of many cluster-based interventions on outcomes, there can be lengthy delays before a trial can commence. In this article, we introduce "batched" stepped wedge designs. Batched stepped wedge designs allow clusters to commence the study in batches, instead of all at once, allowing for staggered cluster recruitment. Like the stepped wedge, the batched stepped wedge rolls out the intervention to all clusters in a randomized and step-wise fashion: a series of self-contained stepped wedge designs. Provided that separate period effects are included for each batch, software for standard stepped wedge sample size calculations can be used. With this time parameterization, in many situations including when linear models are assumed, sample size calculations reduce to the setting of a single stepped wedge design with multiple clusters per sequence. In these situations, sample size calculations will not depend on the delays between the commencement of batches. Hence, the power of batched stepped wedge designs is robust to unexpected delays between batches.

Research on Brand Illustration Innovative Design Modeling Based on Industry 4.0

With China's attention to the requirements of brand illustration innovative design, under the background of Industry 4.0, the advantages of applying 3D modeling method in the field of traditional illustration design are becoming more and more prominent. Based on this, this paper studies the modeling method of brand illustration innovative design based on Industry 4.0 and constructs a 3D analysis model of illustration design based on cattle cooperative hybrid algorithm. This paper innovates the innovative design method of brand illustration under the background of Industry 4.0 from the three aspects of illustration structure, illustration style, and illustration creation method, uses the cattle cooperative hybrid algorithm to quantify its innovation, and realizes the intelligent evaluation of its innovation and the quantitative representation of modeling method based on the illustration database. The experimental results show that the illustration innovative design analysis model based on cattle collaborative hybrid algorithm can effectively combine the industrial 4.0 background, realize the modeling innovation at the three-dimensional level, and significantly improve its innovative design efficiency and modeling success rate.

Testing implementation facilitation for uptake of an evidence-based psychosocial intervention in VA homeless programs: A hybrid type III trial

Background

Healthcare systems face difficulty implementing evidence-based practices, particularly multicomponent interventions. Additional challenges occur in settings serving vulnerable populations such as homeless Veterans, given the population’s acuity, multiple service needs, and organizational barriers. Implementation Facilitation (IF) is a strategy to support the uptake of evidence-based practices. This study’s aim was to simultaneously examine IF on the uptake of Maintaining Independence and Sobriety Through Systems Integration, Outreach and Networking-Veterans Edition (MISSION-Vet), an evidence-based multicomponent treatment engagement intervention for homeless Veterans with co-occurring mental health and substance abuse, and clinical outcomes among Veterans receiving MISSION-Vet.

Methods

This multi-site hybrid III modified stepped-wedge trial involved seven programs at two Veterans Affairs Medical Centers comparing Implementation as Usual (IU; training and educational materials) to IF (IU + internal and external facilitation).

Results

A total of 110 facilitation events averaging 27 minutes were conducted, of which 85% were virtual. Staff (case managers and peer specialists; n = 108) were trained in MISSION-Vet and completed organizational readiness assessments (n = 77). Although both sites reported being willing to innovate and a desire to improve outcomes, implementation climate significantly differed. Following IU, no staff at either site conducted MISSION-Vet. Following IF, there was a significant MISSION-Vet implementation difference between sites (53% vs. 14%, p = .002). Among the 93 Veterans that received any MISSION-Vet services, they received an average of six sessions. Significant positive associations were found between number of MISSION-Vet sessions and outpatient treatment engagement measured by the number of outpatient visits attended.

Conclusions

While staff were interested in improving patient outcomes, MISSION-Vet was not implemented with IU. IF supported MISSION-Vet uptake and increased outpatient service utilization, but MISSION-Vet still proved difficult to implement particularly in the larger healthcare system. Future studies might tailor implementation strategies to organizational readiness.

Trial registration

ClinicalTrials.gov, NCT02942979.

Effect of patient-centered transitional care services on patient-reported outcomes in heart failure: sex-specific analysis of the PACT-HF randomized controlled trial

AIMS

We assessed the effect of transitional care on patient-reported outcomes (PROs) in women and men hospitalized for heart failure.

METHODS AND RESULTS

In this sex-specific analysis of a stepped wedge cluster randomized trial in Canada, the effect of a patient-centered transitional care model was tested on pre-specified PROs of discharge preparedness (B-PREPARED score, range 0-22), quality of transition [Care Transitions Measure-3 (CTM-3) score, range 0-100], and health-related quality of life (HRQOL) (EQ-5D-5L, range 0-1). Among 986 patients (47.4% women), B-PREPARED at 6 weeks was greater with the intervention than usual care [mean difference (MD) 4.01 (95% confidence interval-CI 2.90-5.12); P < 0.001], with no sex differences (P sex-interaction = 0.24). CTM-3 at 6 weeks was greater with the intervention than usual care [MD 10.52 (95% CI 6.00-15.04); P < 0.001], with no sex differences (P sex-interaction = 0.69). EQ-5D-5L was greater with intervention than usual care at discharge [MD 0.17 (95% CI 0.12-0.22); P < 0.001], 6 weeks [MD 0.06 (95% CI 0.01-0.12); P = 0.02], and 6 months [MD 0.05 (95% CI -0.01 to 0.12); P = 0.09], although the 6-month difference was not statistically significant. At discharge, women reported lower EQ-5D-5L but experienced significantly greater treatment benefit than men (P sex-interaction = 0.02). Treatment effect on EQ-5D-5L was numerically greater in women than men at 6 weeks and 6 months, but there were no significant sex differences (P sex-interaction 0.18 and 0.19, respectively).

CONCLUSION

A patient-centered transitional care model improved discharge preparedness, transition quality, and HRQOL in the weeks following heart failure hospitalization, with effects largely consistent in women and men. However, women reported lower HRQOL and experienced greater treatment benefit in this endpoint than men at hospital discharge.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT02112227.

Selective prevention of cardiovascular disease using integrated lifestyle intervention in primary care: protocol of the Healthy Heart stepped-wedge trial

INTRODUCTION

Lifestyle interventions are shown to be effective in improving cardiovascular disease (CVD) risk factors. It has been suggested that general practitioners can play an essential role in CVD prevention. However, studies into lifestyle interventions for primary care patients at high cardiovascular risk are scarce and structural implementation of lifestyle interventions can be challenging. Therefore, this study aims to (1) evaluate (cost-)effectiveness of implementation of an integrated group-based lifestyle programme in primary care practices; (2) identify effective intervention elements and (3) identify implementation determinants of an integrated group-based lifestyle intervention for patients with high cardiovascular risk.

METHODS AND ANALYSIS

The Healthy Heart study is a non-randomised cluster stepped-wedge trial. Primary care practices will first offer standard care during a control period of 2-6 months, after which practices will switch (step) to the intervention, offering participants a choice between a group-based lifestyle programme or standard care. Participants enrolled during the control period (standard care) will be compared with participants enrolled during the intervention period (combined standard care and group-based lifestyle intervention). We aim to include 1600 primary care patients with high cardiovascular risk from 55 primary care practices in the area of The Hague, the Netherlands. A mixed-methods process evaluation will be used to simultaneously assess effectiveness and implementation outcomes. The primary outcome measure will be achievement of individual lifestyle goals after 6 months. Secondary outcomes include lifestyle change of five lifestyle components (smoking, alcohol consumption, diet, weight and physical activity) and improvement of quality of life and self-efficacy. Outcomes are assessed using validated questionnaires at baseline and 3, 6, 12 and 24 months of follow-up. Routine care data will be used to compare blood pressure and cholesterol levels. Cost-effectiveness of the lifestyle intervention will be evaluated. Implementation outcomes will be assessed using the RE-AIM model, to assesses five dimensions of implementation at different levels of organisation: reach, efficacy, adoption, implementation and maintenance. Determinants of adoption and implementation will be assessed using focus groups consisting of professionals and patients.

ETHICS AND DISSEMINATION

This study is approved by the Ethics Committee of the Leiden University Medical Center (P17.079). Results will be shared with the primary care group, healthcare providers and patients, and will be disseminated through journal publications and conference presentations.

TRIAL REGISTRATION NUMBER

NL60795.058.17. Status: pre-results.

Reducing Hospital Transfers from Aged Care Facilities: A Large-Scale Stepped Wedge Evaluation

BACKGROUND/OBJECTIVES

Older people living in residential aged care facilities (RACFs) experience acute deterioration requiring assessment and decision making. We evaluated the impact of a large-scale regional Aged Care Emergency (ACE) program in reducing hospital admissions and emergency department (ED) transfers.

DESIGN

A stepped wedge nonrandomized cluster trial with 11 steps, implemented from May 2013 to August 2016.

SETTING

A large regional and rural area of northern and western New South Wales, Australia.

PARTICIPANTS

Nine hospital EDs and 81 RACFs participated in the evaluation.

INTERVENTION

The ACE program is an integrated nurse-led intervention underpinned by a community of practice designed to improve the capability of RACFs managing acutely unwell residents. It includes telephone support, evidence-based algorithms, defining goals of care for ED transfer, case management in the ED, and an education program.

MEASUREMENTS

ED transfers and subsequent hospital admissions were collected from administrative data including 13 months baseline and 9 months follow-up.

RESULTS

A total of 18,837 eligible ED visits were analyzed. After accounting for clustering by RACFs and adjusting for time of the year as well as RACF characteristics, a statistically significant reduction in hospital admissions (adjusted incident rate ratio = .79; 95% confidence interval [CI] = .68-.92); P = .0025) was seen (i.e., residents were 21% less likely to be admitted to the hospital). This was also observed in ED visit rates (adjusted incidence rate ratio = .80; 95% CI = .69-.92; P = .0023) (i.e., residents were 20% less likely to be transferred to the ED). Seven-day ED re-presentation fell from 5.7% to 4.9%, and 30-day hospital readmissions fell from 12% to 10%.

CONCLUSION

The stepped wedge design allowed rigorous evaluation of a real-world large-scale intervention. These results confirm that the ACE program can be scaled up to a large geographic area and can reduce ED visits and hospitalization of older people with complex healthcare needs living in RACFs.