Research Designs for Intervention Research with Small Samples II: Stepped Wedge and Interrupted Time-Series Designs

Continuous individual feedback to nurses at emergency medical dispatch centres: a stepped-wedge, interrupted time series analysis

BACKGROUND

Clinical feedback is often lacking in prehospital care, and while performance data is increasingly available to clinical and operational leadership, it is seldom made available to care providers themselves. In this study, we investigate the impact of a simple intervention consisting of the provision of monthly feedback reports via email to emergency medical dispatch nurses in three Swedish regions.

METHOD

Individualised reports consisting of 14 measures divided into descriptive (eg, priority-setting and call times), process (eg, dispatch times and documentation completeness) and outcome (eg, over/under triage rate) categories were developed with staff and management input. Report delivery was implemented using a stepped-wedge design, and effects were evaluated using a hierarchical regression-based interrupted time series analysis.

RESULTS

40 dispatchers were included in the study between March 2020 and October 2023, who handled a total of 246 353 incidents. Some impacts on documentation-related process measures were identified, with the odds of complete documentation increasing by 7.5% (95% CI 5.1 to 9.9) and the odds of having a documented contact reason increasing by 3.8% (1.5-5.9). These effects remained robust over the post-intervention period. Weaker impacts on outcome measures were identified which could be explained by a higher priority given to emergency medical dispatches overall.

CONCLUSION

Providing performance data can influence care providers to adjust their behaviour to improve process-related quality metrics under their direct control. The intervention may also have induced nurses to more often upgrade the priority of their patients. Improving outcome metrics may however require more intensive, multifaceted interventions.

Staggered interventions with no control groups

The limitations of the two-way fixed effects for the impact evaluation of interventions that occur at different times for each group have meant that 'staggered interventions' have been highlighted in recent years in the econometric literature and, more recently, in epidemiology. Although many alternative strategies (such as staggered difference-in-differences) have been proposed, the focus has predominantly been on scenarios in which one or more control groups are available. However, control groups are often unavailable, due to limitations in the available data or because all units eventually receive the intervention. In this context, interrupted time series (ITS) designs can constitute an appropriate alternative. The extent to which common model specifications for ITS analyses are limited in the case of staggered interventions remains an underexplored area in the methodological literature. In this work, we aim to demonstrate that standard ITS model specifications typically yield biased results for staggered interventions and we propose alternative model specifications that were inspired by recent developments in the difference-in-differences literature to propose adapted analytical strategies.

Effectiveness of IT-supported patient recruitment: study protocol for an interrupted time series study at ten German university hospitals

BACKGROUND

As part of the German Medical Informatics Initiative, the MIRACUM project establishes data integration centers across ten German university hospitals. The embedded MIRACUM Use Case "Alerting in Care - IT Support for Patient Recruitment", aims to support the recruitment into clinical trials by automatically querying the repositories for patients satisfying eligibility criteria and presenting them as screening candidates. The objective of this study is to investigate whether the developed recruitment tool has a positive effect on study recruitment within a multi-center environment by increasing the number of participants. Its secondary objective is the measurement of organizational burden and user satisfaction of the provided IT solution.

METHODS

The study uses an Interrupted Time Series Design with a duration of 15 months. All trials start in the control phase of randomized length with regular recruitment and change to the intervention phase with additional IT support. The intervention consists of the application of a recruitment-support system which uses patient data collected in general care for screening according to specific criteria. The inclusion and exclusion criteria of all selected trials are translated into a machine-readable format using the OHDSI ATLAS tool. All patient data from the data integration centers is regularly checked against these criteria. The primary outcome is the number of participants recruited per trial and week standardized by the targeted number of participants per week and the expected recruitment duration of the specific trial. Secondary outcomes are usability, usefulness, and efficacy of the recruitment support. Sample size calculation based on simple parallel group assumption can demonstrate an effect size of d=0.57 on a significance level of 5% and a power of 80% with a total number of 100 trials (10 per site). Data describing the included trials and the recruitment process is collected at each site. The primary analysis will be conducted using linear mixed models with the actual recruitment number per week and trial standardized by the expected recruitment number per week and trial as the dependent variable.

DISCUSSION

The application of an IT-supported recruitment solution developed in the MIRACUM consortium leads to an increased number of recruited participants in studies at German university hospitals. It supports employees engaged in the recruitment of trial participants and is easy to integrate in their daily work.

POWER Up-Improving pre-exposure prophylaxis (PrEP) uptake among Black cisgender women in the Southern United States: Protocol for a stepped-wedge cluster randomized trial (SW-CRT)

BACKGROUND

HIV disproportionately affects Black/African American cisgender women (hereafter women) in the United States. Despite its proven effectiveness, pre-exposure prophylaxis (PrEP) for HIV prevention remains vastly under-prescribed to women based on their need. Increasing PrEP uptake and persistence among women is crucial to reducing HIV transmission; however, there have been few studies designed specifically for women. This article describes the study protocol used to assess the feasibility, acceptability, and effectiveness of implementation strategies to improve PrEP uptake and persistence among Black women in the Midwest and South.

METHODS

PrEP Optimization among Women to Enhance Retention and Uptake (POWER Up) is an evidence-based, woman-focused set of five implementation science strategies that addresses barriers of PrEP utilization at the provider, patient, and clinic levels. POWER Up includes 1) routine PrEP education for patients, 2) standardized provider training, 3) electronic medical record (EMR) optimization, 4) PrEP navigation, and 5) PrEP clinical champions. These strategies will be adapted to specific clinics for implementation, tested via a stepped-wedge trial, and, if effective, packaged for further dissemination.

DISCUSSION

We will utilize a stepped-wedge cluster randomized trial (SW-CRT) to measure change in PrEP utilization across diverse geographic areas. Preparation for adapting and implementing the bundle of strategies is needed to determine how to tailor them to specific clinics. Implementation challenges will include adapting strategies with the available resources at each site, maintaining stakeholder involvement and staff buy-in, adjusting the study protocol and planned procedures as needed, and ensuring minimal crossover. Additionally, strengths and limitations of each strategy must be examined before, during, and after the adaptation and implementation processes. Finally, the implementation outcomes of the strategies must be evaluated to determine the real-world success of the strategies. This study is an important step toward addressing the inequity in PrEP service delivery and increasing PrEP utilization among Black women in the U.S.

Linking Primary Care Patients to Mental Health Care via Behavioral Health Social Workers: A Stepped-Wedge Study

OBJECTIVE

Demand for systematic linkage of patients to behavioral health care has increased because of the widespread implementation of depression screening. This study assessed the impact of deploying behavioral health social workers (BHSWs) in primary care on behavioral health visits for depression or anxiety.

METHODS

This quasi-experimental, stepped-wedge study included adults with a primary care visit between 2016 and 2019 at Cleveland Clinic, a large integrated health system. BHSWs were deployed in 40 practices between 2017 and 2019. Patients were allocated to a control group (diagnosed before BHSW deployment) and an intervention group (diagnosed after deployment). Data were collected on behavioral health visits (i.e., to therapists and psychiatrists) within 30 days of the diagnosis. Multilevel logistic regression models identified associations between BHSW deployment period and behavioral health visit, adjusted for demographic variables and clustering within each group.

RESULTS

Of 68,659 persons with a diagnosis, 21% had a depression diagnosis, 49% an anxiety diagnosis, and 31% both diagnoses. In the period after BHSW deployment, the proportion of patients with depression who had a behavioral health visit increased by 10 percentage points, of patients with anxiety by 9 percentage points, and of patients with both disorders by 11 percentage points. The adjusted odds of having a behavioral health visit was higher in the postdeployment period for patients with depression (adjusted odds ratio [AOR]=4.35, 95% confidence interval [CI]=3.50-5.41), anxiety (AOR=4.27, 95% CI=3.57-5.11), and both (AOR= 3.26, 95% CI=2.77-3.84).

CONCLUSIONS

Integration of BHSWs in primary care was associated with increased behavioral health visits.

Brief modular approach to target perceived burdensomeness in clinic-referred youth

INTRODUCTION

Existing CBT protocols for internalizing disorders target thoughts and behaviors related to anxiety and/or depression, but do not explicitly target other identified risk factors for suicide ideation, including perceived burdensomeness toward others. The aims of the current study were to (1) develop a novel, brief module (the "Give program") targeting perceived burdensomeness toward others that can be embedded within existing CBT protocols for youth internalizing disorders, (2) evaluate the acceptability and feasibility of the module with an eye toward intervention refinement, and (3) examine reductions in perceived burdensomeness.

METHODS

Participants were 18 clinic-referred youths with anxiety or depressive disorders who endorsed burdensomeness. We used a quasi-experimental interrupted time-series design to evaluate changes in burdensomeness scores following the administration of the module.

RESULTS

The module was clinically feasible and well-accepted. Youth burdensomeness scores increased in the first half of the CBT protocol and decreased immediately following the administration of the Give program module. Burdensomeness scores were significantly associated with suicide ideation.

CONCLUSION

The current study is the first to develop and evaluate a module targeting burdensomeness in at-risk youth in an outpatient setting, demonstrating that burdensomeness can be efficiently and effectively targeted within existing evidence-based treatment protocols for internalizing disorders in youth.

The Impact of Eye-gaze Controlled Computer on Communication and Functional Independence in Children and Young People with Complex Needs - A Multicenter Intervention Study

INTRODUCTION

Children and young people with complex needs (severe motor impairments and without speech) have few opportunities to use alternative devices for communication. Eye-gaze controlled computers (EGCCs) might provide individuals with complex needs increased opportunities for communication and participation in society.

OBJECTIVE

To investigate the impact of EGCCs on communication, functional independence and participation in activities in children and young people with complex needs.

METHODS

A multicenter intervention study during seven months, measuring outcomes with or without EGCC at four time points, was conducted in Sweden, Dubai, and in USA. Seventeen participants (aged 3-26 years, diagnosis e.g. cerebral palsy, Rett syndrome) were provided with EGCC and services from an Assistive Technology center to implement EGCC in school and/or at home.

RESULTS

Participants significantly increased their expressive communication skills and functional independence with EGCC compared to baseline. All but one (16 of 17) increased their activity repertoire and computer use with EGCC. With EGCC, participation in computer activities averaged 4.1 performed activities (e.g. communication, play), with a duration of 70 minutes/day and a frequency of 76% of days.

DISCUSSION

The study strengthened the research evidence that EGCC can be an effective intervention in daily life for children and young people with complex needs. Communication and independence, common goals of intervention, were shown to be relevant EGCC outcomes.

Patient and Family Engagement in Catheter-Associated Urinary Tract Infection (CAUTI) Prevention: A Systematic Review

BACKGROUND

Catheter-associated urinary tract infections (CAUTIs) are detrimental to health and are largely preventable with adherence to CAUTI prevention guidelines. Patient and family engagement in CAUTI prevention is often encouraged in these guidelines; however, little is known about how this engagement is operationalized in practice. A systematic review was conducted to synthesize the content, format, and outcomes of interventions that engage patients and/or families in CAUTI prevention.

METHODS

Two reviewers independently screened records from four databases up to March 2021 and searched reference lists of final articles. Included articles were primary research, tested an intervention, involved indwelling urinary catheters, and described at least one patient and/or family engagement method. Articles were appraised for quality using the Downs and Black checklist.

RESULTS

After 720 records were screened, 12 were included. Study quality ranged from good to poor, scoring lowest in internal validity. The most common formats of patient/family engagement were flyers/handouts (83.3%) and verbal education (58.3%). Common content areas were urinary catheter care and maintenance strategies. Most study outcomes (83.3%) measured CAUTI rates, and half measured patient/family-related outcomes. Improvements were seen in at least one outcome across all studies, but less than half (41.7%) showed statistically significant results.

CONCLUSION

The researchers found that most interventions lacked sufficient detail on the content, delivery, and/or outcome measurement of patient/family engagement, which limits transferability. More high-quality, generalizable trials are warranted in this area. Future research should focus on integrating publicly available resources into practice that can be tested for comprehension and revised based on feedback from target audiences.

Cluster-randomized trial comparing organizationally tailored versus standard approach for integrating an evidence-based cancer control intervention into African American churches

The field of implementation science has devoted increasing attention to optimizing the fit of evidence-based interventions to the organizational settings in which they are delivered. Institutionalization of health promotion into routine organizational operations is one way to achieve this. However, less is known about how to maximize fit and achieve institutionalization, particularly in settings outside of the healthcare system. This paper reports on findings from a parallel cluster-randomized trial that compared an organizationally tailored with a standard (core components only) approach for institutionalizing ("integrating") an evidence-based cancer control intervention into African American churches. Churches randomized to the organizationally tailored condition identified three or more implementation strategies from a menu of 20, with an implementation time frame for each. The primary study outcome was assessed through the Faith-Based Organization Health Integration Inventory, a measure of institutionalization of health promotion activities in church settings, completed by pastors at baseline and 12-month follow-up. Seventeen churches were randomized and 14 were analyzed as 3 did not implement the study protocol. Though the percent increase in total integration score was greater in the tailored condition (N = 9; 18%) than in the standard condition (N = 5; 12%), linear mixed-effect models did not detect a statistically significant group × time interaction. Despite the challenges of integrating health promotion activities outside of healthcare organizations, the current approach shows promise for fostering sustainable health promotion in community settings and merits further study.

Effects of terrorist attacks on access to maternal healthcare services: a national longitudinal study in Burkina Faso

INTRODUCTION

Most of the literature on terrorist attacks' health impacts has focused on direct victims rather than on distal consequences in the overall population. There is limited knowledge on how terrorist attacks can be detrimental to access to healthcare services. The objective of this study is to assess the impact of terrorist attacks on the utilisation of maternal healthcare services by examining the case of Burkina Faso.

METHODS

This longitudinal quasi-experimental study uses multiple interrupted time series analysis. Utilisation of healthcare services data was extracted from the National Health Information System in Burkina Faso. Data span the period of January 2013-December 2018 and include all public primary healthcare centres and district hospitals. Terrorist attack data were extracted from the Armed Conflict Location and Event Data project. Negative binomial regression models were fitted with fixed effects to isolate the immediate and long-term effects of terrorist attacks on three outcomes (antenatal care visits, of facility deliveries and of cesarean sections).

RESULTS

During the next month of an attack, the incidence of assisted deliveries in healthcare facilities is significantly reduced by 3.8% (95% CI 1.3 to 6.3). Multiple attacks have immediate effects more pronounced than single attacks. Longitudinal analysis show that the incremental number of terrorist attacks is associated with a decrease of the three outcomes. For every additional attack in a commune, the incidence of cesarean sections is reduced by 7.7% (95% CI 4.7 to 10.7) while, for assisted deliveries, it is reduced by 2.5% (95% CI 1.9 to 3.1) and, for antenatal care visits, by 1.8% (95% CI 1.2 to 2.5).

CONCLUSION

Terrorist attacks constitute a new barrier to access of maternal healthcare in Burkina Faso. The exponential increase in terrorist activities in West Africa is expected to have negative effects on maternal health in the entire region.

Essential Ingredients and Innovations in the Design and Analysis of Group-Randomized Trials

This article reviews the essential ingredients and innovations in the design and analysis of group-randomized trials. The methods literature for these trials has grown steadily since they were introduced to the biomedical research community in the late 1970s, and we summarize those developments. We review, in addition to the group-randomized trial, methods for two closely related designs, the individually randomized group treatment trial and the stepped-wedge group-randomized trial. After describing the essential ingredients for these designs, we review the most important developments in the evolution of their methods using a new bibliometric tool developed at the National Institutes of Health. We then discuss the questions to be considered when selecting from among these designs or selecting the traditional randomized controlled trial. We close with a review of current methods for the analysis of data from these designs, a case study to illustrate each design, and a brief summary.

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.

Immersive Nature-Experiences as Health Promotion Interventions for Healthy, Vulnerable, and Sick Populations? A Systematic Review and Appraisal of Controlled Studies

In this systematic review, we summarized and evaluated the evidence for effects of, and associations between, immersive nature-experience on mental, physical, and social health promotion outcomes. Immersive nature-experience was operationalized as non-competitive activities, both sedentary and active, occurring in natural environments removed from everyday environments. We defined health according to the World Health Organization's holistic and positive definition of health and included steady-state, intermediate, and health promotion outcomes. An electronic search was performed for Danish, English, German, Norwegian, and Swedish articles published between January 2004 and May 2017. Manual approaches, e.g., bibliographies from experts, supplemented the literature search. Data were extracted from 461 publications that met the inclusion criteria. To assess the status and quality of the evidence for health promotion effects of immersive nature-experience, we focused on the subset of studies based on controlled designs (n = 133). Outcome level quality of the evidence was assessed narratively. Interventions most often involved adventure-based activities, short-termed walking, and seated relaxation in natural environments. We found positive effects on a range of health promotion outcomes grouped under psychological wellbeing (n = 97; ≈55% positive; ≈13% mixed; ≈29% non-significant; 2% negative); psychosocial function (n = 67; ≈61% positive; ≈9% mixed; ≈30% non-significant); psychophysiological stress response (n = 50; ≈58% positive; ≈18% mixed; ≈24% non-significant), and cognitive performance (n = 36; ≈58% positive; ≈6% mixed; ≈33% non-significant; 3% negative); and social skills and relationships (n = 34; ≈70% positive; ≈7% mixed; ≈22% non-significant). Findings related to outcomes categorized under physical health, e.g., risk of cardiovascular disease, were less consistent (n = 51; ≈37% positive; ≈28% mixed; ≈35% non-significant). Across the types of interventions and outcomes, the quality of the evidence was deemed low and occasionally moderate. In the review, we identify, discuss, and present possible solutions to four core methodological challenges associated with investigating immersive nature-experience and health outcomes: (1) intervention and program complexity; (2) feasibility and desirability of randomization; (3) blinding of participants and researchers; and (4) transferability and generalizability. The results of the review have been published as a popular-scientific report and a scientific research overview, both in Danish language.

Mixed effects approach to the analysis of the stepped wedge cluster randomised trial-Investigating the confounding effect of time through simulation

BACKGROUND

A stepped wedge cluster randomised trial (SWCRT) is a multicentred study which allows an intervention to be rolled out at sites in a random order. Once the intervention is initiated at a site, all participants within that site remain exposed to the intervention for the remainder of the study. The time since the start of the study ("calendar time") may affect outcome measures through underlying time trends or periodicity. The time since the intervention was introduced to a site ("exposure time") may also affect outcomes cumulatively for successful interventions, possibly in addition to a step change when the intervention began.

METHODS

Motivated by a SWCRT of self-monitoring for bipolar disorder, we conducted a simulation study to compare model formulations to analyse data from a SWCRT under 36 different scenarios in which time was related to the outcome (improvement in mood score). The aim was to find a model specification that would produce reliable estimates of intervention effects under different scenarios. Nine different formulations of a linear mixed effects model were fitted to these datasets. These models varied in the specification of calendar and exposure times.

RESULTS

Modelling the effects of the intervention was best accomplished by including terms for both calendar time and exposure time. Treating time as categorical (a separate parameter for each measurement time-step) achieved the best coverage probabilities and low bias, but at a cost of wider confidence intervals compared to simpler models for those scenarios which were sufficiently modelled by fewer parameters. Treating time as continuous and including a quadratic time term performed similarly well, with slightly larger variations in coverage probability, but narrower confidence intervals and in some cases lower bias. The impact of misspecifying the covariance structure was comparatively small.

CONCLUSIONS

We recommend that unless there is a priori information to indicate the form of the relationship between time and outcomes, data from SWCRTs should be analysed with a linear mixed effects model that includes separate categorical terms for calendar time and exposure time. Prespecified sensitivity analyses should consider the different formulations of these time effects in the model, to assess their impact on estimates of intervention effects.

Alternatives to Randomized Control Trial Designs for Community-Based Prevention Evaluation

Multiple factors may complicate evaluation of preventive interventions, particularly in situations where the randomized controlled trial (RCT) is impractical, culturally unacceptable, or ethically questionable, as can occur with community-based efforts focused on inner-city neighborhoods or rural American Indian/Alaska Native communities. This paper is based in the premise that all research designs, including RCTs, are constrained by the extent to which they can refute the counterfactual and by which they can meet the challenge of proving the absence of effects due to the intervention-that is, showing what is prevented. Yet, these requirements also provide benchmarks for valuing alternatives to RCTs, those that have shown abilities to estimate preventive effects and refute the counterfactual with limited bias acting in congruence with community values about implementation. In this paper, we describe a number of research designs with attending examples, including regression discontinuity, interrupted time series designs, and roll-out randomization designs. We also set forth procedures and practices that can enhance their utility. Alternative designs, when combined with such design strengths, can provide valid evaluations of community-based interventions as viable alternatives to the RCT.

Selecting and Improving Quasi-Experimental Designs in Effectiveness and Implementation Research

Interventional researchers face many design challenges when assessing intervention implementation in real-world settings. Intervention implementation requires holding fast on internal validity needs while incorporating external validity considerations (such as uptake by diverse subpopulations, acceptability, cost, and sustainability). Quasi-experimental designs (QEDs) are increasingly employed to achieve a balance between internal and external validity. Although these designs are often referred to and summarized in terms of logistical benefits, there is still uncertainty about (a) selecting from among various QEDs and (b) developing strategies to strengthen the internal and external validity of QEDs. We focus here on commonly used QEDs (prepost designs with nonequivalent control groups, interrupted time series, and stepped-wedge designs) and discuss several variants that maximize internal and external validity at the design, execution and implementation, and analysis stages.

Navigare necesse est! Research to understand our body and soul, to heal the patients, to find ourselves

The image of a researcher is a distinguished, enthusiastic doctor in a fresh, washed and ironed white lab coat working in a clinic or research-centre. The research is well-financed, supported by different scientific and/or economic firms, and the aim is to understand the human body and its physiologic processes in atomic level for getting the best, mostly very expensive, and sometimes uneasy medical treatment for the patient. Nowadays on top of the most modern sciences there is the specialist, who lives in an ivory tower and knows almost everything about diseases and sciences. Try to get off to this land!

Multi-Level Cultural Intervention for the Prevention of Suicide and Alcohol Use Risk with Alaska Native Youth: a Nonrandomized Comparison of Treatment Intensity

Suicide and alcohol use disorders are primary determinants of health disparity among Alaska Native people in contrast to the US general population. Qungasvik, a Yup'ik word for toolbox, is a strengths-based, multi-level, community/cultural intervention for rural Yup'ik youth ages 12-18. The intervention uses "culture as intervention" to promote reasons for life and sobriety in young people using local expertise, high levels of community direction, and community based staff. The intervention is grounded in local practices and adaptive to local cultural differences distinctive to rural Yup'ik communities. The current study compares the effectiveness of high-intensity intervention in one community (treatment), operationalized as a high number of intervention activities, or modules, implemented and attended by youth, contrasted to a lower intensity intervention in a second community (comparison) that implemented fewer modules. A Yup'ik Indigenous theory of change developed through previous qualitative and quantitative work guides intervention. In the model, direct intervention effects on proximal or intermediate variables constituting protective factors at the individual, family, community, and peer influences levels lead to later change on the ultimate prevention outcome variables of Reasons for Life protective from suicide risk and Reflective Processes about alcohol use consequences protective from alcohol risk. Mixed effects regression models contrasted treatment and comparison arms, and identified significant intervention effects on Reasons for Life (d = 0.27, p < .05) but not Reflective Processes.

Effect of interrupting free healthcare for children: Drawing lessons at the critical moment of national scale-up in Burkina Faso

With solid evidence that free healthcare increases the utilization of health services, Burkina Faso recently exempted all children under five and pregnant women from direct payment at health facilities. However, there is little insight into the capacity to maintain the gains attributable to free healthcare under routine conditions of implementation at the national scale. In particular, the repercussions of its interruption are unknown. The objective is to assess the effects of a sequence of natural interventions including the introduction, interruption and reintroduction of free healthcare on health-seeking practices and utilization of healthcare facilities by children under five. This is an embedded mixed methods study conducted in Kaya district, Burkina Faso. The quantitative component is based on a reversal longitudinal design. Pooled interrupted time-series analysis was performed to assess changes in the monthly number of visits from January 2005 to March 2015. Qualitative data were collected through in-depth interviews with health personnel and mothers to better understand the quantitative results. The results show that visits to health centres dropped immediately and significantly when free healthcare was interrupted (-146, CI_95% [-255; -37]). They increased again when free healthcare was reintroduced (+89, CI_95% [-11; 187]). Both urban and rural centres were affected. Self-medication and visits to traditional healers were reported more frequently during the withdrawal of free healthcare, and tensions between the population and health personnel increased. Implementation problems other than insufficient funding limited the coverage or intensity of free healthcare. While removing user fees could potentially improve mothers and children's health in Burkina Faso, this study shows that demand for healthcare remains highly sensitive to price changes. Gains in utilization attributable to free healthcare may vanish rapidly if user fees are reintroduced. It is essential to support an effective and sustainable implementation of this ambitious initiative.

Recommendations for Cancer Epidemiologic Research in Understudied Populations and Implications for Future Needs

Medically underserved populations in the United States continue to experience higher cancer burdens of incidence, mortality, and other cancer-related outcomes. It is imperative to understand how health inequities experienced by diverse population groups may contribute to our increasing unequal cancer burdens and disparate outcomes. The National Cancer Institute convened a diverse group of scientists to discuss research challenges and opportunities for cancer epidemiology in medically underserved and understudied populations. This report summarizes salient issues and discusses five recommendations from the group, including the next steps required to better examine and address cancer burden in the United States among our rapidly increasing diverse and understudied populations. Cancer Epidemiol Biomarkers Prev; 25(4); 573-80. ©2016 AACR SEE ALL ARTICLES IN THIS CEBP FOCUS SECTION, "MULTILEVEL APPROACHES TO ADDRESSING CANCER HEALTH DISPARITIES".

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.

Reversible improvement in severe freezing of gait from Parkinson's disease with unilateral interleaved subthalamic brain stimulation

Freezing of gait causes considerable morbidity in patients with Parkinson's disease and is often refractory to conventional treatments. In this double-blind, randomized evaluation, unilateral interleaved deep brain stimulation in the subthalamic nucleus/substantia nigra pars reticulata region significantly improved freezing of gait in a patient with advanced Parkinson's disease.

Maybe Small Is Too Small a Term: Introduction to Advancing Small Sample Prevention Science

Prevention research addressing health disparities often involves work with small population groups experiencing such disparities. The goals of this special section are to (1) address the question of what constitutes a small sample; (2) identify some of the key research design and analytic issues that arise in prevention research with small samples; (3) develop applied, problem-oriented, and methodologically innovative solutions to these design and analytic issues; and (4) evaluate the potential role of these innovative solutions in describing phenomena, testing theory, and evaluating interventions in prevention research. Through these efforts, we hope to promote broader application of these methodological innovations. We also seek whenever possible, to explore their implications in more general problems that appear in research with small samples but concern all areas of prevention research. This special section includes two sections. The first section aims to provide input for researchers at the design phase, while the second focuses on analysis. Each article describes an innovative solution to one or more challenges posed by the analysis of small samples, with special emphasis on testing for intervention effects in prevention research. A concluding article summarizes some of their broader implications, along with conclusions regarding future directions in research with small samples in prevention science. Finally, a commentary provides the perspective of the federal agencies that sponsored the conference that gave rise to this special section.