Mixed methods evaluation of targeted case finding for cardiovascular disease prevention using a stepped wedged cluster RCT

Considerations Before Selecting a Stepped-Wedge Cluster Randomized Trial Design for a Practice Improvement Study

PURPOSE

Despite the growing popularity of stepped-wedge cluster randomized trials (SW-CRTs) for practice-based research, the design's advantages and challenges are not well documented. The objective of this study was to identify the advantages and challenges of the SW-CRT design for large-scale intervention implementations in primary care settings.

METHODS

The EvidenceNOW: Advancing Heart Health initiative, funded by the Agency for Healthcare Research and Quality, included a large collection of SW-CRTs. We conducted qualitative interviews with 17 key informants from EvidenceNOW grantees to identify the advantages and challenges of using SW-CRT design.

RESULTS

All interviewees reported that SW-CRT can be an effective study design for large-scale intervention implementations. Advantages included (1) incentivized recruitment, (2) staggered resource allocation, and (3) statistical power. Challenges included (1) time-sensitive recruitment, (2) retention, (3) randomization requirements and practice preferences, (4) achieving treatment schedule fidelity, (5) intensive data collection, (6) the Hawthorne effect, and (7) temporal trends.

CONCLUSIONS

The challenges experienced by EvidenceNOW grantees suggest that certain favorable real-world conditions constitute a context that increases the odds of a successful SW-CRT. An existing infrastructure can support the recruitment of many practices. Strong retention plans are needed to continue to engage sites waiting to start the intervention. Finally, study outcomes should be ones already captured in routine practice; otherwise, funders and investigators should assess the feasibility and cost of data collection.VISUAL ABSTRACT.

What should selective cardiometabolic prevention programmes in European primary care look like? A consensus-based design by the SPIMEU group

Background: Selective prevention of cardiometabolic diseases (CMD)—that is, preventive measures specifically targeting the high-risk population—may represent the most effective approach for mitigating rising CMD rates.

Objectives: To develop a universal concept of selective CMD prevention that can guide implementation within European primary care.

Methods: Initially, 32 statements covering different aspects of selective CMD prevention programmes were identified based on a synthesis of evidence from two systematic literature reviews and surveys conducted within the SPIMEU project. The Rand/UCLA appropriateness method (RAM) was used to find consensus on these statements among an international panel consisting of 14 experts. Before the consensus meeting, statements were rated by the experts in a first round. In the next step, during a face-to-face meeting, experts were provided with the results of the first rating and were then invited to discuss and rescore the statements in a second round.

Results: In the outcome of the RAM procedure, 28 of 31 statements were considered appropriate and three were rated uncertain. The panel deleted one statement. Selective CMD prevention was considered an effective approach for preventing CMD and a proactive approach was regarded as more effective compared to case-finding alone. The most efficient method to implement selective CMD prevention systematically in primary care relies on a stepwise approach: initial risk assessment followed by interventions if indicated.

Conclusion: The final set of statements represents the key characteristics of selective CMD prevention and can serve as a guide for implementing selective prevention actions in European primary care.

Digital Recruitment and Acceptance of a Stepwise Model to Prevent Chronic Disease in the Danish Primary Care Sector: Cross-Sectional Study

Background

During recent years, stepwise approaches to health checks have been advanced as an alternative to general health checks. In 2013, we set up the Early Detection and Prevention project (Tidlig Opsporing og Forebyggelse, TOF) to develop a stepwise approach aimed at patients at high or moderate risk of a chronic disease. A novel feature was the use of a personal digital mailbox for recruiting participants. A personal digital mailbox is a secure digital mailbox provided by the Danish public authorities. Apart from being both safe and secure, it is a low-cost, quick, and easy way to reach Danish residents.

Objective

In this study we analyze the association between the rates of acceptance of 2 digital invitations sent to a personal digital mailbox and the sociodemographic determinants, medical treatment, and health care usage in a stepwise primary care model for the prevention of chronic diseases.

Methods

We conducted a cross-sectional analysis of the rates of acceptance of 2 digital invitations sent to randomly selected residents born between 1957 and 1986 and residing in 2 Danish municipalities. The outcome was acceptance of the 2 digital invitations. Statistical associations were determined by Poisson regression. Data-driven chi-square automatic interaction detection method was used to generate a decision tree analysis, predicting acceptance of the digital invitations.

Results

A total of 8814 patients received an invitation in their digital mailbox from 47 general practitioners. A total of 40.22% (3545/8814) accepted the first digital invitation, and 30.19 % (2661/8814) accepted both digital invitations. The rates of acceptance of both digital invitations were higher among women, older patients, patients of higher socioeconomic status, and patients not diagnosed with or being treated for diabetes mellitus, chronic obstructive pulmonary disease, or cardiovascular disease.

Conclusions

To our knowledge, this is the first study to report on the rates of acceptance of digital invitations to participate in a stepwise model for prevention of chronic diseases. More studies of digital invitations are needed to determine if the acceptance rates seen in this study should be expected from future studies as well. Similarly, more research is needed to determine whether a multimodal recruitment approach, including digital invitations to personal digital mailboxes will reach hard-to-reach subpopulations more effectively than digital invitations only.

Targeted prevention in primary care aimed at lifestyle-related diseases: a study protocol for a non-randomised pilot study

BACKGROUND

The consequences of lifestyle-related disease represent a major burden for the individual as well as for society at large. Individual preventive health checks to the general population have been suggested as a mean to reduce the burden of lifestyle-related diseases, though with mixed evidence on effectiveness. Several systematic reviews, on the other hand, suggest that health checks targeting people at high risk of chronic lifestyle-related diseases may be more effective. The evidence is however very limited. To effectively target people at high risk of lifestyle-related disease, there is a substantial need to advance and implement evidence-based health strategies and interventions that facilitate the identification and management of people at high risk. This paper reports on a non-randomized pilot study carried out to test the acceptability, feasibility and short-term effects of a healthcare intervention in primary care designed to systematically identify persons at risk of developing lifestyle-related disease or who engage in health-risk behavior, and provide targeted and coherent preventive services to these individuals.

METHODS

The intervention took place over a three-month period from September 2016 to December 2016. Taking a two-pronged approach, the design included both a joint and a targeted intervention. The former was directed at the entire population, while the latter specifically focused on patients at high risk of a lifestyle-related disease and/or who engage in health-risk behavior. The intervention was facilitated by a digital support system. The evaluation of the pilot will comprise both quantitative and qualitative research methods. All outcome measures are based on validated instruments and aim to provide results pertaining to intervention acceptability, feasibility, and short-term effects.

DISCUSSION

This pilot study will provide a solid empirical base from which to plan and implement a full-scale randomized study with the central aim of determining the efficacy of a preventive health intervention.

TRIAL REGISTRATION

Registered at Clinical Trial Gov (Unique Protocol ID: TOFpilot2016 ). Registered 29 April 2016. The study adheres to the SPIRIT guidelines.

NHS Health Check comorbidity and management: an observational matched study in primary care

BACKGROUND

The NHS Health Check programme completed its first 5 years in 2014, identifying those at highest risk of cardiovascular disease and new comorbidities, and offering behavioural change support and treatment.

AIM

To describe the coverage and impact of this programme on cardiovascular risk management and identification of new comorbidities.

DESIGN AND SETTING

Observational 5-year study from April 2009 to March 2014, in 139 of 143 general practices in three clinical commissioning groups (CCGs) in east London.

METHOD

A matched analysis compared comorbidity in NHS Health Check attendees and non-attendees.

RESULTS

A total of 252 259 adults aged 40-74 years were eligible for an NHS Health Check and, of these, 85 122 attended in 5 years. Attendance increased from 7.3% (10 900/149 867) in 2009 to 17.0% (18 459/108 525) in 2013 to 2014, representing increasing coverage from 36.4% to 85.0%. Attendance was higher in the more deprived quintiles and among South Asians. Statins were prescribed to 11.5% of attendees and 8.2% of non-attendees. In a matched analysis, newly-diagnosed comorbidity was more likely in attendees than non-attendees, with odds ratios for new diabetes 1.30 (95% confidence interval [CI] = 1.21 to 1.39), hypertension 1.50 (95% CI = 1.43 to 1.57), and chronic kidney disease 1.83 (95% CI = 1.52 to 2.21).

CONCLUSION

The NHS Health Check programme provision in these CCGs was equitable, with recent coverage of 85%. Statins were 40% more likely to be prescribed to attendees than non-attendees, providing estimated absolute benefits of public health importance. More new cases of diabetes, hypertension, and chronic kidney disease were identified among attendees than a matched group of non-attendees.

Targeted case finding in the prevention of cardiovascular disease: a stepped wedge cluster randomised controlled trial

BACKGROUND

Individuals at high risk of cardiovascular disease (CVD) are undertreated.

AIM

To evaluate the effectiveness of a programme of targeted, nurse-led case finding for CVD prevention in primary care.

DESIGN AND SETTING

Targeted case finding for CVD prevention was implemented in urban West Midlands general practices between February 2009 and August 2012, and evaluated as a stepped wedge cluster randomised trial.

METHOD

Untreated patients aged 35-74 years and at ≥20% 10-year CVD risk were identified, invited for assessment by a project nurse, and referred to their GP for treatment initiation. The primary outcome was the proportion of high-risk patients prescribed antihypertensives or statins after exposure to the intervention compared with an equivalent period of time prior to exposure. Secondary outcomes included assessment of CVD risk factors.

RESULTS

In 26 sequentially randomised general practices the exposed group consisted of 2926 untreated high-risk patients identified at the start of the intervention, with 2969 patients identified at the start of the unexposed period. The trial was well balanced in terms of age, sex, and cardiovascular risk factors. In the exposed period 19.7% of patients were prescribed antihypertensives or statins, and 10.8% of patients in the unexposed period. After adjustment for clustering and temporal effects the risk difference was 15.5% (95% CI = 3.9 to 27.1, P = 0.009). Assessment of lipid levels increased significantly, at 26.4% (99% CI = 5.3 to 47.5, P = 0.001) CONCLUSION: Targeted case finding programmes can increase the number of high-risk patients started on antihypertensive and statin treatment.

Stepped wedge cluster randomised trials: a review of the statistical methodology used and available

BACKGROUND

Previous reviews have focussed on the rationale for employing the stepped wedge design (SWD), the areas of research to which the design has been applied and the general characteristics of the design. However these did not focus on the statistical methods nor addressed the appropriateness of sample size methods used.This was a review of the literature of the statistical methodology used in stepped wedge cluster randomised trials.

METHODS

Literature Review. The Medline, Embase, PsycINFO, CINAHL and Cochrane databases were searched for methodological guides and RCTs which employed the stepped wedge design.

RESULTS

This review identified 102 trials which employed the stepped wedge design compared to 37 from the most recent review by Beard et al. 2015. Forty six trials were cohort designs and 45 % (n = 46) had fewer than 10 clusters. Of the 42 articles discussing the design methodology 10 covered analysis and seven covered sample size. For cohort stepped wedge designs there was only one paper considering analysis and one considering sample size methods. Most trials employed either a GEE or mixed model approach to analysis (n = 77) but only 22 trials (22 %) estimated sample size in a way which accounted for the stepped wedge design that was subsequently used.

CONCLUSIONS

Many studies which employ the stepped wedge design have few clusters but use methods of analysis which may require more clusters for unbiased and efficient intervention effect estimates. There is the need for research on the minimum number of clusters required for both types of stepped wedge design. Researchers should distinguish in the sample size calculation between cohort and cross sectional stepped wedge designs. Further research is needed on the effect of adjusting for the potential confounding of time on the study power.

Systematic versus opportunistic risk assessment for the primary prevention of cardiovascular disease

BACKGROUND

Screening programmes can potentially identify people at high cardiovascular risk and reduce cardiovascular disease (CVD) morbidity and mortality. However, there is currently not enough evidence showing clear clinical or economic benefits of systematic screening-like programmes over the widely practised opportunistic risk assessment of CVD in primary care settings.

OBJECTIVES

The primary objective of this review was to assess the effectiveness, costs and adverse effects of systematic risk assessment compared to opportunistic risk assessment for the primary prevention of CVD.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library, MEDLINE, EMBASE on 30 January 2015, and Web of Science Core Collection and additional databases on the Cochrane Library on 4 December 2014. We also searched two clinical trial registers and checked reference lists of relevant articles. We applied no language restrictions.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) that assessed the effects of systematic risk assessment, defined as a screening-like programme involving a predetermined selection process of people, compared with opportunistic risk assessment which ranged from no risk assessment at all to incentivised case finding of CVD and related risk factors. Participants included healthy adults from the general population, including those who are at risk of CVD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies. One review author extracted data and assessed them for risk of bias and a second checked them. We assessed evidence quality using the GRADE approach and present this in a 'Summary of findings' table.

MAIN RESULTS

Nine completed RCTs met the inclusion criteria, of which four were cluster-randomised. We also identified five ongoing trials. The included studies had a high or unclear risk of bias, and the GRADE ratings of overall quality were low or very low. The length of follow-up varied from one year in four studies, three years in one study, five or six years in two studies, and ten years in two studies. Eight studies recruited participants from the general population, although there were differences in the age ranges targeted. One study recruited family members of cardiac patients (high risk assessment). There were considerable differences between the studies in the interventions received by the intervention and control groups. There was insufficient evidence to stratify by the types of risk assessment approaches.Limited data were available on all-cause mortality (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.92 to 1.02; 3 studies,103,571 participants, I² = 0%; low-quality evidence) and cardiovascular mortality (RR 1.00, 95% CI 0.90 to 1.11; 2 studies, 43,955 participants, I² = 0%), and suggest that screening has no effect on these outcomes. Data were also limited for combined non-fatal endpoints; overall, evidence indicates no difference in total coronary heart disease (RR 1.01, 95% CI 0.95 to 1.07; 4 studies, 5 comparisons, 110,168 participants, I² = 0%; low-quality evidence), non-fatal coronary heart disease (RR 0.98, 95% CI 0.89 to 1.09; 2 studies, 43,955 participants, I² = 39%), total stroke (RR 0.99, 95% CI 0.90 to 1.10; 2 studies, 79,631 participants, I² = 0%, low-quality evidence), and non-fatal stroke (RR 1.17, 95% CI 0.94 to 1.47; 1 study, 20,015 participants).Overall, systematic risk assessment appears to result in lower total cholesterol levels (mean difference (MD) -0.11 mmol/l, 95% CI -0.17 to -0.04, 6 studies, 7 comparisons, 12,591 participants, I² = 57%; very low-quality evidence), lower systolic blood pressure (MD -3.05 mmHg, 95% CI -4.84 to -1.25, 6 studies, 7 comparisons, 12,591 participants, I² = 82%; very low-quality evidence) and lower diastolic blood pressure (MD -1.34 mmHg, 95% CI -1.76 to -0.93, 6 studies, 7 comparisons, 12,591 participants, I² = 0%; low-quality evidence). One study assessed adverse effects and found no difference in psychological distress at five years (1126 participants).

AUTHORS' CONCLUSIONS

The results are limited by the heterogeneity between trials in terms of participants recruited, interventions and duration of follow-up. Limited data suggest that systematic risk assessment for CVD has no statistically significant effects on clinical endpoints. There is limited evidence to suggest that CVD systematic risk assessment may have some favourable effects on cardiovascular risk factors. The completion of the five ongoing trials will add to the evidence base.

Stepped wedge randomised controlled trials: systematic review of studies published between 2010 and 2014

BACKGROUND

In a stepped wedge, cluster randomised trial, clusters receive the intervention at different time points, and the order in which they received it is randomised. Previous systematic reviews of stepped wedge trials have documented a steady rise in their use between 1987 and 2010, which was attributed to the design's perceived logistical and analytical advantages. However, the interventions included in these systematic reviews were often poorly reported and did not adequately describe the analysis and/or methodology used. Since 2010, a number of additional stepped wedge trials have been published. This article aims to update previous systematic reviews, and consider what interventions were tested and the rationale given for using a stepped wedge design.

METHODS

We searched PubMed, PsychINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Web of Science, the Cochrane Library and the Current Controlled Trials Register for articles published between January 2010 and May 2014. We considered stepped wedge randomised controlled trials in all fields of research. We independently extracted data from retrieved articles and reviewed them. Interventions were then coded using the functions specified by the Behaviour Change Wheel, and for behaviour change techniques using a validated taxonomy.

RESULTS

Our review identified 37 stepped wedge trials, reported in 10 articles presenting trial results, one conference abstract, 21 protocol or study design articles and five trial registrations. These were mostly conducted in developed countries (n = 30), and within healthcare organisations (n = 28). A total of 33 of the interventions were educationally based, with the most commonly used behaviour change techniques being 'instruction on how to perform a behaviour' (n = 32) and 'persuasive source' (n = 25). Authors gave a wide range of reasons for the use of the stepped wedge trial design, including ethical considerations, logistical, financial and methodological. The adequacy of reporting varied across studies: many did not provide sufficient detail regarding the methodology or calculation of the required sample size.

CONCLUSIONS

The popularity of stepped wedge trials has increased since 2010, predominantly in high-income countries. However, there is a need for further guidance on their reporting and analysis.

Designing a stepped wedge trial: three main designs, carry-over effects and randomisation approaches

BACKGROUND

There is limited guidance on the design of stepped wedge cluster randomised trials. Current methodological literature focuses mainly on trials with cross-sectional data collection at discrete times, yet many recent stepped wedge trials do not follow this design. In this article, we present a typology to characterise the full range of stepped wedge designs, and offer guidance on several other design aspects.

METHODS

We developed a framework to define and report the key characteristics of a stepped wedge trial, including cluster allocation and individual participation. We also considered the relative strengths and weaknesses of trials according to this framework. We classified recently published stepped wedge trials using this framework and identified illustrative case studies. We identified key design choices and developed guidance for each.

RESULTS

We identified three main stepped wedge designs: those with a closed cohort, an open cohort, and a continuous recruitment short exposure design. In the first two designs, many individuals experience both control and intervention conditions. In the final design, individuals are recruited in continuous time as they become eligible and experience either the control or intervention condition, but not both, and then provide an outcome measurement at follow-up. While most stepped wedge trials use simple randomisation, stratification and restricted randomisation are often feasible and may be useful. Some recent studies collect outcome information from individuals exposed a long time before or after the rollout period, but this contributes little to the primary analysis. Incomplete designs should be considered when the intervention cannot be implemented quickly. Carry-over effects can arise in stepped wedge trials with closed and open cohorts.

CONCLUSIONS

Stepped wedge trial designs should be reported more clearly. Researchers should consider the use of stratified and/or restricted randomisation. Trials should generally not commit resources to collect outcome data from individuals exposed a long time before or after the rollout period. Though substantial carry-over effects are uncommon in stepped wedge trials, researchers should consider their possibility before conducting a trial with closed or open cohorts.

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.

Stepped-wedge cluster randomised controlled trials: a generic framework including parallel and multiple-level designs

Stepped-wedge cluster randomised trials (SW-CRTs) are being used with increasing frequency in health service evaluation. Conventionally, these studies are cross-sectional in design with equally spaced steps, with an equal number of clusters randomised at each step and data collected at each and every step. Here we introduce several variations on this design and consider implications for power.

One modification we consider is the incomplete cross-sectional SW-CRT, where the number of clusters varies at each step or where at some steps, for example, implementation or transition periods, data are not collected. We show that the parallel CRT with staggered but balanced randomisation can be considered a special case of the incomplete SW-CRT. As too can the parallel CRT with baseline measures. And we extend these designs to allow for multiple layers of clustering, for example, wards within a hospital. Building on results for complete designs, power and detectable difference are derived using a Wald test and obtaining the variance–covariance matrix of the treatment effect assuming a generalised linear mixed model. These variations are illustrated by several real examples.

We recommend that whilst the impact of transition periods on power is likely to be small, where they are a feature of the design they should be incorporated. We also show examples in which the power of a SW-CRT increases as the intra-cluster correlation (ICC) increases and demonstrate that the impact of the ICC is likely to be smaller in a SW-CRT compared with a parallel CRT, especially where there are multiple levels of clustering. Finally, through this unified framework, the efficiency of the SW-CRT and the parallel CRT can be compared.