Cluster Randomized Trials in Comparative Effectiveness Research: Randomizing Hospitals to Test Methods for Prevention of Healthcare-Associated Infections

Direct Gloving vs Hand Hygiene Before Donning Gloves in Adherence to Hospital Infection Control Practices: A Cluster Randomized Clinical Trial

Importance

Current guidelines require hand hygiene before donning nonsterile gloves, but evidence to support this requirement is lacking.

Objective

To evaluate the effectiveness of a direct-gloving policy on adherence to infection prevention practices in a hospital setting.

Design, Setting, and Participants

This mixed-method, multicenter, cluster randomized clinical trial was conducted at 4 academic centers in Baltimore, Maryland, or Iowa City, Iowa, from January 1, 2016, to November 30, 2017. Data analysis was completed April 25, 2019. Participants were 3790 health care personnel (HCP) across 13 hospital units.

Intervention

Hospital units were randomly assigned to direct gloving, with hand hygiene not required before donning gloves (intervention), or to usual care (hand hygiene before donning nonsterile gloves).

Main Outcomes and Measures

The primary outcome was adherence to the expected practice at room entry and exit. A random sample of HCPs' gloved hands were imprinted on agar plates at entry to contact precautions rooms. The intention-to-treat approach was followed, and all analyses were conducted at the level of the participating unit. Primary and secondary outcomes between treatment groups were assessed using generalized estimating equations with an unstructured working correlation matrix to adjust for clustering; multivariate analysis using generalized estimating equations was conducted to adjust for covariates, including baseline adherence.

Results

In total, 13 hospital units participated in the trial, and 3790 HCP were observed. Adherence to expected practice was greater in the 6 units with the direct-gloving intervention than in the 7 usual care units (1297 of 1491 [87%] vs 954 of 2299 [41%]; P < .001) even when controlling for baseline hand hygiene rates, unit type, and universal gloving policies (risk ratio [RR], 1.76; 95% CI, 1.58-1.97). Glove use on entry to contact precautions rooms was also higher in the direct-gloving units (1297 of 1491 [87%] vs 1530 of 2299 [67%]; P = .008. The intervention had no effect on hand hygiene adherence measured at entry to non-contact precautions rooms (951 of 1315 [72%] for usual care vs 1111 of 1688 [66%] for direct gloving; RR, 1.00 [95% CI, 0.91-1.10]) or at room exit (1587 of 1897 [84%] for usual care vs 1525 of 1785 [85%] for direct gloving; RR, 0.98 [95% CI, 0.91-1.07]). The intervention was associated with increased total bacteria colony counts (adjusted incidence RR, 7.13; 95% CI, 3.95-12.85) and greater detection of pathogenic bacteria (adjusted incidence RR, 10.18; 95% CI, 2.13-44.94) on gloves in the emergency department and reduced colony counts in pediatrics units (adjusted incidence RR, 0.34; 95% CI, 0.19-0.63), with no change in either total colony count (RR, 0.87 [95% CI, 0.60 to 1.25] for adult intensive care unit; RR, 0.59 [95% CI, 0.31-1.10] for hemodialysis unit) or presence of pathogenic bacteria (RR, 0.93 [95% CI, 0.40-2.14] for adult intensive care unit; RR, 0.55 [95% CI, 0.15-2.04] for hemodialysis unit) in the other units.

Conclusions and Relevance

Current guidelines require hand hygiene before donning nonsterile gloves, but evidence to support this requirement is lacking. The findings from this cluster randomized clinical trial indicate that a direct-gloving strategy without prior hand hygiene should be considered by health care facilities.

Trial Registration

ClinicalTrials.gov Identifier: NCT03119389.

Bias-corrected and doubly robust inference for the three-level longitudinal cluster-randomized trials with missing continuous outcomes and small number of clusters: Simulation study and application to a study for adults with serious mental illnesses

Longitudinal cluster-randomized designs have been popular tools for comparative effective research in clinical trials. The methodologies for the three-level hierarchical design with longitudinal outcomes need to be better understood under more pragmatic settings; that is, with a small number of clusters, heterogeneous cluster sizes, and missing outcomes. Generalized estimating equations (GEEs) have been frequently used when the distribution of data and the correlation model are unknown. Standard GEEs lead to bias and an inflated type I error rate due to the small number of available clinics and non-completely random missing data in longitudinal outcomes. We evaluate the performance of inverse probability weighted (IPW) estimating equations, with and without augmentation, for two types of missing data in continuous outcomes and individual-level treatment allocation mechanisms combined with two bias-corrected variance estimators. Our intensive simulation results suggest that the proposed augmented IPW method with bias-corrected variance estimation successfully prevents the inflation of false positive findings and improves efficiency when the number of clinics is small, with moderate to severe missing outcomes. Our findings are expected to aid researchers in choosing appropriate analysis methods for three-level longitudinal cluster-randomized designs. The proposed approaches were applied to analyze data from a longitudinal cluster-randomized clinical trial involving adults with serious mental illnesses.

The impact of healthcare executive seniority on implementation of innovative methods of diagnosis and prevention

Innovative methods of diagnosis and prevention play a key role in the survival of healthcare systems as well as the wellbeing of patients. Effective healthcare management is a critical factor in implementing hospital innovation. Healthcare executive (HE) personal and job characteristics such as age and seniority have been found to affect innovative decision-making. However, no study has yet investigated age and seniority effects on the propensity to implement innovation in health prevention strategies. This study fills the literature gap by providing evidence for the effect of HE age and seniority on the implementation of innovative methods for diagnosis and prevention. Predicated on 57 in-depth interviews with HEs, we employ mixed methods research, combining qualitative and quantitative analysis. Structural Equation Modeling was used to test the model's goodness-of-fit. Results show that while HE age and number of years in the organization positively affect job tenure, job tenure, in turn, negatively affects willingness to implement innovative methods of diagnosis and prevention in hospitals. This study extends the Upper-Echelon Theory to health workforce management. Practical implications are discussed.

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.

Strategies for facilitating the delivery of cluster randomized trials in hospitals: A study informed by the CFIR-ERIC matching tool

BACKGROUND

Recruitment and engagement of clusters in a cluster randomized controlled trial can sometimes prove challenging. Identification of successful or unsuccessful strategies may be beneficial in guiding future researchers in conducting their cluster randomized controlled trial. This study aimed to identify strategies that could be used to facilitate the delivery of cluster randomized controlled trials in hospitals.

METHODS

The study employed the Consolidated Framework for Implementation Research-Expert Recommendations for Implementing Change matching tool. The barriers and enablers to cluster randomized controlled trial conduct identified in our previously conducted studies served as a means of determinant identification for the conduct of cluster randomized controlled trials. These determinants were mapped to Consolidated Framework for Implementation Research constructs and then matched to Expert Recommendations for Implementing Change compilation strategies using the Consolidated Framework for Implementation Research-Expert Recommendations for Implementing Change matching tool.

RESULTS

The Expert Recommendations for Implementing Change strategies matched to at least one determinant Consolidated Framework for Implementation Research construct were as follows: (1) 'Identify and prepare champions', (2) 'Conduct local needs assessment', (3) 'Conduct educational meetings', (4) 'Inform local opinion leaders', (5) 'Build a coalition', (6) 'Promote adaptability', (7) 'Develop a formal implementation blueprint', (8) 'Involve patients/consumers and family members', (9) 'Obtain and use patients/consumers and family feedback', (10) 'Develop educational materials', (11) 'Promote network weaving', (12) 'Distribute educational materials', (13) 'Access new funding' and (14) 'Develop academic partnerships'.

CONCLUSION

This study was intended as a step in the research agenda aimed at facilitating cluster randomized controlled trial delivery in hospitals and can act as a resource for future researchers when planning their cluster randomized controlled trial, with the expectation that the strategies identified here will be tailored to each context.

How the Cluster-randomized Trial "Works"

Cluster-randomized trials (CRTs) are able to address research questions that randomized controlled trials (RCTs) of individual patients cannot answer. Of great interest for infectious disease physicians and infection control practitioners are research questions relating to the impact of interventions on infectious disease dynamics at the whole-of-population level. However, there are important conceptual differences between CRTs and RCTs relating to design, analysis, and inference. These differences can be illustrated by the adage "peas in a pod." Does the question of interest relate to the "peas" (the individual patients) or the "pods" (the clusters)? Several examples of recent CRTs of community and intensive care unit infection prevention interventions are used to illustrate these key concepts. Examples of differences between the results of RCTs and CRTs on the same topic are given.

Determining the Suitability of Registries for Embedding Clinical Trials in the United States: A Project of the Clinical Trials Transformation Initiative

BACKGROUND

Patient registries are organized systems that use observational methods to collect uniform data on specified outcomes in a population defined by a particular disease, condition, or exposure. Data collected in registries often coincide with data that could support clinical trials. Integrating clinical trials within registries to create registry-embedded clinical trials offers opportunities to reduce duplicative data collection, identify and recruit patients more efficiently, decrease time to database lock, accelerate time to regulatory decision-making, and reduce clinical trial costs. This article describes a project of the Clinical Trials Transformation Initiative (CTTI) intended to help clinical trials researchers determine when a registry could potentially serve as the platform for the conduct of a clinical trial.

METHODS

Through a review of registry-embedded clinical trials and commentaries, semi-structured interviews with experts, and a multi-stakeholder expert meeting, the project team addressed how to identify and describe essential registry characteristics, practices, and processes required to for conducting embedded clinical trials intended for regulatory submissions in the United States.

RESULTS

Recommendations, suggested practices, and decision trees that facilitate the assessment of whether a registry is suitable for embedding clinical trials were developed, as well as considerations for the design of new registries. Essential registry characteristics include relevancy, robustness, reliability, and assurance of patient protections.

CONCLUSIONS

The project identifies a clear role for registries in creating a sustainable and reusable infrastructure to conduct clinical trials. Adoption of these recommendations will facilitate the ability to perform high-quality and efficient prospective registry-based clinical trials.

The role of medical smartphone apps in clinical decision-support: A literature review

INTRODUCTION

The now ubiquitous smartphone has huge potential to assist clinical decision-making across the globe. However, the rapid pace of digitalisation contrasts starkly with the slower rate of medical research and publication. This review explores the evidence base that exists to validate and evaluate the use of medical decision-support apps. The resultant findings will inform appropriate and pragmatic evaluation strategies for future clinical app developers and provide a scientific and cultural context for research priorities in this field.

METHOD

Medline, Embase and Cochrane databases were searched for clinical trials concerning decision support and smart phones from 2007 (introduction of first smartphone iPhone) until January 2019.

RESULTS

Following exclusions, 48 trials and one Cochrane review were included for final analysis. Whilst diagnostic accuracy studies are plentiful, clinical trials are scarce. App research methodology was further interrogated according to setting and decision-support modality: e.g. camera-based, guideline-based, predictive models. Description of app development pathways and regulation were highly varied. Global health emerged as an early adopter of decision-support apps and this field is leading implementation and evaluation.

CONCLUSION

Clinical decision-support apps have considerable potential to enhance access to care and quality of care, but the medical community must rise to the challenge of modernising its approach if it is truly committed to capitalising on the opportunities of digitalisation.

Unique aspects of clinical trials of invasive therapies for chronic pain

Nearly all who review the literature conclude that the role of invasive procedures to treat chronic pain is poorly characterized because of the lack of “definitive” studies. The overt nature of invasive treatments, along with the risks, technical skills, and costs involved create challenges to study them. However, these challenges do not completely preclude evaluating invasive procedure effectiveness and safety using well-designed methods. This article reviews the challenges of studying outcomes of invasive therapies to treat pain and discuss possible solutions. Although the following discussion can apply to most invasive therapies to treat chronic pain, it is beyond the scope of the article to individually cover every invasive therapy used. Therefore, most of the examples focus on injection therapies to treat spine pain, spinal cord stimulation, and intrathecal drug therapies.

The role of randomized cluster crossover trials for comparative effectiveness testing in anesthesia: design of the Benzodiazepine-Free Cardiac Anesthesia for Reduction in Postoperative Delirium (B-Free) trial

Increasingly, clinicians and researchers recognize that studies of interventions need to evaluate not only their therapeutic efficacy (i.e., the effect on an outcome in ideal, controlled settings) but also their real-world effectiveness in broad, unselected patient groups. Effectiveness trials inform clinical practice by comparing variations in therapeutic approaches that fall within the standard of care. In this article, we discuss the need for studies of comparative effectiveness in anesthesia and the limitations of individual patient randomized-controlled trials in determining comparative effectiveness. We introduce the concept of randomized cluster crossover trials as a means of answering questions of comparative effectiveness in anesthesia, using the design of the Benzodiazepine-Free Cardiac Anesthesia for Reduction in Postoperative Delirium (B-Free) trial (Clinicaltrials.gov identifier NCT03053869).

Guanxinning tablet for patients who switch from dual antiplatelet therapy to aspirin alone after percutaneous coronary intervention: study protocol for a cluster randomized controlled trial

Background

One-year dual antiplatelet therapy (DAPT), generally aspirin in combination with a P2Y12 receptor inhibitor, has been a standard treatment for patients undergoing percutaneous coronary intervention (PCI). Prolonged DAPT has proven itself effective in further reducing cardiovascular events, yet with increased risk of bleeding. Thus, it is of great necessity to find an alternative drug that is as effective but safer and more economic than the P2Y12 inhibitors after termination of one-year DAPT.

Methods

We will conduct a cluster randomized controlled trial in 3600 eligible post-PCI patients from 36 tertiary hospitals (100 patients per hospital) across mainland China. The hospitals served as clusters are randomized in a 2:1 ratio to Guanxinning tablet (GXNT) plus aspirin or aspirin alone for 12 months, with other conventional treatment applied in both groups. After the treatment period, all patients will be followed up for another 12 months. The primary outcome measure is composite cardiovascular events including cardiovascular death, non-fatal myocardial infarction, stent thrombosis, revascularization, ischemic stroke, and re-admission due to unstable angina. Secondary outcome measures are all-cause mortality, each individual component of the primary outcome measure, and stopping or reducing the rate of nitroglycerin administration. Adverse events, including bleeding, will be closely monitored during the whole trial period. In addition, a cost-effectiveness study of GXNT for the study population will be conducted along with this trial.

Discussion

This trial aims to determine whether the addition of GXNT will further improve prognosis without increasing bleeding risk for patients with coronary artery disease who have switched from DAPT to aspirin alone after PCI. Completion of this clinical trial might provide a novel, promising, and safer alternative to P2Y12 inhibitors for prolonged antiplatelet therapy in post-PCI patients.

Trial registration

Chinese Clinical Trial Registry, ChiCTR-IIR-17010688. Registered on 20 February 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-017-2373-x) contains supplementary material, which is available to authorized users.

Anticipated Ethics and Regulatory Challenges in PCORnet: The National Patient-Centered Clinical Research Network

PCORnet, the National Patient-Centered Clinical Research Network, seeks to establish a robust national health data network for patient-centered comparative effectiveness research. This article reports the results of a PCORnet survey designed to identify the ethics and regulatory challenges anticipated in network implementation. A 12-item online survey was developed by leadership of the PCORnet Ethics and Regulatory Task Force; responses were collected from the 29 PCORnet networks. The most pressing ethics issues identified related to informed consent, patient engagement, privacy and confidentiality, and data sharing. High priority regulatory issues included IRB coordination, privacy and confidentiality, informed consent, and data sharing. Over 150 IRBs and five different approaches to managing multisite IRB review were identified within PCORnet. Further empirical and scholarly work, as well as practical and policy guidance, is essential if important initiatives that rely on comparative effectiveness research are to move forward.

Gloves, gowns and masks for reducing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in the hospital setting

BACKGROUND

Meticillin-resistant Staphylococcus aureus (MRSA; also known as methicillin-resistant S aureus) is a common hospital-acquired pathogen that increases morbidity, mortality, and healthcare costs. Its control continues to be an unresolved issue in many hospitals worldwide. The evidence base for the effects of the use of gloves, gowns or masks as control measures for MRSA is unclear.

OBJECTIVES

To assess the effectiveness of wearing gloves, a gown or a mask when contact is anticipated with a hospitalised patient colonised or infected with MRSA, or with the patient's immediate environment.

SEARCH METHODS

We searched the Specialised Registers of three Cochrane Groups (Wounds Group on 5 June 2015; Effective Practice and Organisation of Care (EPOC) Group on 9 July 2013; and Infectious Diseases Group on 5 January 2009); CENTRAL (The Cochrane Library 2015, Issue 6); DARE, HTA, NHS EED, and the Methodology Register (The Cochrane Library 2015, Issue 6); MEDLINE and MEDLINE In-Process & Other Non-Indexed Citations (1946 to June week 1 2015); EMBASE (1974 to 4 June 2015); Web of Science (WOS) Core Collection (from inception to 7 June 2015); CINAHL (1982 to 5 June 2015); British Nursing Index (1985 to 6 July 2010); and ProQuest Dissertations & Theses Database (1639 to 11 June 2015). We also searched three trials registers (on 6 June 2015), references list of articles, and conference proceedings. We finally contacted relevant individuals for additional studies.

SELECTION CRITERIA

Studies assessing the effects on MRSA transmission of the use of gloves, gowns or masks by any person in the hospital setting when contact is anticipated with a hospitalised patient colonised or infected with MRSA, or with the patient's immediate environment. We did not assess adverse effects or economic issues associated with these interventions.We considered any comparator to be eligible. With regard to study design, only randomised controlled trials (clustered or not) and the following non-randomised experimental studies were eligible: quasi-randomised controlled trials (clustered or not), non-randomised controlled trials (clustered or not), controlled before-and-after studies, controlled cohort before-after studies, interrupted time series studies (controlled or not), and repeated measures studies. We did not exclude any study on the basis of language or date of publication.

DATA COLLECTION AND ANALYSIS

Two review authors independently decided on eligibility of the studies. Had any study having been included, two review authors would have extracted data (at least for outcome data) and assessed the risk of bias independently. We would have followed the standard methodological procedures suggested by Cochrane and the Cochrane EPOC Group for assessing risk of bias and analysing the data.

MAIN RESULTS

We identified no eligible studies for this review, either completed or ongoing.

AUTHORS' CONCLUSIONS

We found no studies assessing the effects of wearing gloves, gowns or masks for contact with MRSA hospitalised patients, or with their immediate environment, on the transmission of MRSA to patients, hospital staff, patients' caregivers or visitors. This absence of evidence should not be interpreted as evidence of no effect for these interventions. The effects of gloves, gowns and masks in these circumstances have yet to be determined by rigorous experimental studies, such as cluster-randomised trials involving multiple wards or hospitals, or interrupted time series studies.

The Effect of Universal Glove and Gown Use on Adverse Events in Intensive Care Unit Patients

BACKGROUND

No randomized trials have examined the effect of contact precautions or universal glove and gown use on adverse events. We assessed if wearing gloves and gowns during all patient contact in the intensive care unit (ICU) changes adverse event rates.

METHODS

From January 2012 to October 2012, intervention ICUs of the 20-site Benefits of Universal Gloving and Gowning cluster randomized trial required that healthcare workers use gloves and gowns for all patient contact. We randomly sampled 1800 medical records of adult patients not colonized with antibiotic-resistant bacteria and reviewed them for adverse events using the Institute for Healthcare Improvement Global Trigger Tool.

RESULTS

Four hundred forty-seven patients (24.8%) had 1 or more ICU adverse events. Adverse events were not associated with universal glove and gown use (incidence rate ratio [IRR], 0.81; 95% confidence interval [CI], .48-1.36). This did not change with adjustment for ICU type, severity of illness, academic hospital status, and ICU size, (IRR, 0.91; 95% CI, .59-1.42; P = .68). Rates of infectious adverse events also did not differ after adjusting for the same factors (IRR, 0.75; 95% CI, .47-1.21; P = .24).

CONCLUSIONS

In ICUs where healthcare workers donned gloves and gowns for all patient contact, patients were no more likely to experience adverse events than in control ICUs. Concerns of adverse events resulting from universal glove and gown use were not supported. Similar considerations may be appropriate regarding use of contact precautions.

CLINICAL TRIALS REGISTRATION

NCT0131821.

The effect of cluster size variability on statistical power in cluster-randomized trials

The frequency of cluster-randomized trials (CRTs) in peer-reviewed literature has increased exponentially over the past two decades. CRTs are a valuable tool for studying interventions that cannot be effectively implemented or randomized at the individual level. However, some aspects of the design and analysis of data from CRTs are more complex than those for individually randomized controlled trials. One of the key components to designing a successful CRT is calculating the proper sample size (i.e. number of clusters) needed to attain an acceptable level of statistical power. In order to do this, a researcher must make assumptions about the value of several variables, including a fixed mean cluster size. In practice, cluster size can often vary dramatically. Few studies account for the effect of cluster size variation when assessing the statistical power for a given trial. We conducted a simulation study to investigate how the statistical power of CRTs changes with variable cluster sizes. In general, we observed that increases in cluster size variability lead to a decrease in power.

Sample size determination for three-level randomized clinical trials with randomization at the first or second level

Clinical trials in the context of comparative effectiveness research (CER) are often conducted to evaluate health outcomes under real-world conditions and standard health care settings. In such settings, three-level hierarchical study designs are increasingly common. For example, patients may be nested within treating physicians, who in turn are nested within an urgent care center or hospital. While many trials randomize the third-level units (e.g., centers) to intervention, in some cases randomization may occur at lower levels of the hierarchy, such as patients or physicians. In this article, we present and verify explicit closed-form sample size and power formulas for three-level designs assuming randomization is at the first or second level. The formulas are based on maximum likelihood estimates from mixed-effect linear models and verified by simulation studies. Results indicate that even with smaller sample sizes, theoretical power derived with known variances is nearly identical to empirically estimated power for the more realistic setting when variances are unknown. In addition, we show that randomization at the second or first level of the hierarchy provides an increasingly statistically efficient alternative to third-level randomization. Power to detect a treatment effect under second-level randomization approaches that of patient-level randomization when there are few patients within each randomized second-level cluster and, most importantly, when the correlation attributable to second-level variation is a small proportion of the overall correlation between patient outcomes.

The evolving landscape of healthcare-associated infections: recent advances in prevention and a road map for research

This white paper identifies knowledge gaps and new challenges in healthcare epidemiology research, assesses the progress made toward addressing research priorities, provides the Society for Healthcare Epidemiology of America (SHEA) Research Committee's recommendations for high-priority research topics, and proposes a road map for making progress toward these goals. It updates the 2010 SHEA Research Committee document, "Charting the Course for the Future of Science in Healthcare Epidemiology: Results of a Survey of the Membership of SHEA," which called for a national approach to healthcare-associated infections (HAIs) and a prioritized research agenda. This paper highlights recent studies that have advanced our understanding of HAIs, the establishment of the SHEA Research Network as a collaborative infrastructure to address research questions, prevention initiatives at state and national levels, changes in reporting and payment requirements, and new patterns in antimicrobial resistance.

Targeted versus universal decolonization to prevent ICU infection

BACKGROUND

Both targeted decolonization and universal decolonization of patients in intensive care units (ICUs) are candidate strategies to prevent health care-associated infections, particularly those caused by methicillin-resistant Staphylococcus aureus (MRSA).

METHODS

We conducted a pragmatic, cluster-randomized trial. Hospitals were randomly assigned to one of three strategies, with all adult ICUs in a given hospital assigned to the same strategy. Group 1 implemented MRSA screening and isolation; group 2, targeted decolonization (i.e., screening, isolation, and decolonization of MRSA carriers); and group 3, universal decolonization (i.e., no screening, and decolonization of all patients). Proportional-hazards models were used to assess differences in infection reductions across the study groups, with clustering according to hospital.

RESULTS

A total of 43 hospitals (including 74 ICUs and 74,256 patients during the intervention period) underwent randomization. In the intervention period versus the baseline period, modeled hazard ratios for MRSA clinical isolates were 0.92 for screening and isolation (crude rate, 3.2 vs. 3.4 isolates per 1000 days), 0.75 for targeted decolonization (3.2 vs. 4.3 isolates per 1000 days), and 0.63 for universal decolonization (2.1 vs. 3.4 isolates per 1000 days) (P=0.01 for test of all groups being equal). In the intervention versus baseline periods, hazard ratios for bloodstream infection with any pathogen in the three groups were 0.99 (crude rate, 4.1 vs. 4.2 infections per 1000 days), 0.78 (3.7 vs. 4.8 infections per 1000 days), and 0.56 (3.6 vs. 6.1 infections per 1000 days), respectively (P<0.001 for test of all groups being equal). Universal decolonization resulted in a significantly greater reduction in the rate of all bloodstream infections than either targeted decolonization or screening and isolation. One bloodstream infection was prevented per 54 patients who underwent decolonization. The reductions in rates of MRSA bloodstream infection were similar to those of all bloodstream infections, but the difference was not significant. Adverse events, which occurred in 7 patients, were mild and related to chlorhexidine.

CONCLUSIONS

In routine ICU practice, universal decolonization was more effective than targeted decolonization or screening and isolation in reducing rates of MRSA clinical isolates and bloodstream infection from any pathogen. (Funded by the Agency for Healthcare Research and the Centers for Disease Control and Prevention; REDUCE MRSA ClinicalTrials.gov number, NCT00980980).

Reanimación y prevención de las infecciones nosocomiales

Los servicios de reanimación deben organizar de forma minuciosa la prevención de infecciones en sus enfermos, ya que éstos suelen estar inmunodeprimidos, están sometidos a múltiples procedimientos invasivos realizados por un personal sanitario variado, a menudo en situaciones de urgencia y a cualquier hora del día o de la noche. Las principales infecciones que hay que tratar de prevenir son las neumonías bacterianas adquiridas asociadas a ventilación mecánica (NAVM), las infecciones relacionadas con catéteres intravasculares y las infecciones urinarias asociadas al sondeo vesical. La incidencia de estas infecciones ha disminuido en la mayoría de los servicios que realizan un control cifrado, sobre todo gracias a la implantación de programas de mejora de la calidad. Las técnicas de prevención son múltiples y deben aplicarse simultáneamente. Incluyen medidas globales, como las modalidades de prevención de la transmisión cruzada (higiene de las manos, sobre todo) o de uso de antibióticos, concebidas para reducir la presión de selección de bacterias resistentes a éstos, así como medidas específicas relativas a la colocación y uso de cada uno de los dispositivos invasivos. Numerosas técnicas han demostrado su eficacia en estudios de buen nivel metodológico (higiene de las manos, apósitos para catéteres, etc.), mientras que otras siguen siendo objeto de controversias, por lo que las recomendaciones nacionales e internacionales se actualizan regularmente de acuerdo con los nuevos datos científicos. Estas medidas, implantadas de manera razonada en el marco de programas de mejora de la calidad, permiten obtener tasas muy bajas de infecciones relacionadas con el uso de catéteres vasculares y resultados menos satisfactorios con las NAVM, que justifican la necesidad de proseguir la investigación en este campo.

Rianimazione e prevenzione delle infezioni nosocomiali

I servizi di rianimazione devono organizzare la prevenzione delle infezioni nei loro pazienti in modo minuzioso, in quanto i pazienti sono spesso immunodepressi e subiscono gesti invasivi molteplici, realizzati da personale differente, spesso in situazioni di urgenza e a qualsiasi ora del giorno o della notte. Le principali infezioni che bisogna tentare di prevenire sono le polmoniti batteriche acquisite sotto ventilazione meccanica (PAVM), le infezioni su cateteri intravascolari e le infezioni urinarie su catetere vescicale. L’incidenza di queste infezioni è diminuita nella maggior parte dei servizi che ne effettuano un monitoraggio su base numerica, in particolare nel quadro di programmi di miglioramento della qualità. Le tecniche di prevenzione sono molteplici e devono essere applicate simultaneamente. Esse riguardano delle misure globali, come le modalità di prevenzione della trasmissione crociata (igiene delle mani, in particolare) o di utilizzo degli antibiotici nella prospettiva di ridurre la pressione di selezione di batteri resistenti agli antibiotici, così come delle misure specifiche relative al posizionamento e all’utilizzo di ciascuno dei dispositivi invasivi. Numerose tecniche si sono dimostrate efficaci in studi di buon livello metodologico (igiene delle mani, medicazioni dei cateteri, ecc.) mentre altre sono ancora oggetto di controversie, portando a raccomandazioni nazionali e internazionali regolarmente aggiornate in funzione dei nuovi dati scientifici. Queste misure, implementate in modo ragionato nel quadro di programmi di miglioramento della qualità, consentono di ottenere dei tassi molto bassi per quanto riguarda le infezioni dei cateteri vascolari e dei risultati meno buoni per le PAVM, illustrando la necessità di proseguire la ricerca in questo settore.

From hot hands to declining effects: the risks of small numbers

About 25 years ago, a group of researchers demonstrated that there is no such thing as the "hot hand" in professional basketball. When a player hits 5 or 7 shots in a row (or misses 10 in a row), what's at work is random variation, nothing more. However, random causes do not stop players, coaches, fans, and media from talking about and acting on "hot hands," telling stories and making choices that ultimately are based on randomness. The same phenomenon is true in medicine. Some clinical trials with small numbers of events yielded positive findings, which in turn led clinicians, academics, and government officials to talk, telling stories and sometimes making choices that were later shown to be based on randomness. I provide some cardiovascular examples, such as the use of angiotensin receptor blockers for chronic heart failure, nesiritide for acute heart failure, and cytochrome P-450 (CYP) 2C19 genotyping for the acute coronary syndromes. I also review the more general "decline effect," by which drugs appear to yield a lower effect size over time. The decline effect is due at least in part to over interpretation of small studies, which are more likely to be noticed because of publication bias. As funders of research, we at the National Heart, Lung, and Blood Institute seek to support projects that will yield robust, credible evidence that will affect practice and policy in the right way. We must be alert to the risks of small numbers.

The role for pragmatic randomized controlled trials (pRCTs) in comparative effectiveness research

There is a growing appreciation that our current approach to clinical research leaves important gaps in evidence from the perspective of patients, clinicians, and payers wishing to make evidence-based clinical and health policy decisions. This has been a major driver in the rapid increase in interest in comparative effectiveness research (CER), which aims to compare the benefits, risks, and sometimes costs of alternative health-care interventions in 'the real world'. While a broad range of experimental and nonexperimental methods will be used in conducting CER studies, many important questions are likely to require experimental approaches - that is, randomized controlled trials (RCTs). Concerns about the generalizability, feasibility, and cost of RCTs have been frequently articulated in CER method discussions. Pragmatic RCTs (or 'pRCTs') are intended to maintain the internal validity of RCTs while being designed and implemented in ways that would better address the demand for evidence about real-world risks and benefits for informing clinical and health policy decisions. While the level of interest and activity in conducting pRCTs is increasing, many challenges remain for their routine use. This article discusses those challenges and offers some potential ways forward.

Empirical power and sample size calculations for cluster-randomized and cluster-randomized crossover studies

In recent years, the number of studies using a cluster-randomized design has grown dramatically. In addition, the cluster-randomized crossover design has been touted as a methodological advance that can increase efficiency of cluster-randomized studies in certain situations. While the cluster-randomized crossover trial has become a popular tool, standards of design, analysis, reporting and implementation have not been established for this emergent design. We address one particular aspect of cluster-randomized and cluster-randomized crossover trial design: estimating statistical power. We present a general framework for estimating power via simulation in cluster-randomized studies with or without one or more crossover periods. We have implemented this framework in the clusterPower software package for R, freely available online from the Comprehensive R Archive Network. Our simulation framework is easy to implement and users may customize the methods used for data analysis. We give four examples of using the software in practice. The clusterPower package could play an important role in the design of future cluster-randomized and cluster-randomized crossover studies. This work is the first to establish a universal method for calculating power for both cluster-randomized and cluster-randomized clinical trials. More research is needed to develop standardized and recommended methodology for cluster-randomized crossover studies.

The role of comparative effectiveness research in transfusion medicine clinical trials: proceedings of a National Heart, Lung, and Blood Institute workshop

Comparative effectiveness research (CER) is the study of existing treatments or ways to deliver health care to determine what intervention works best under specific circumstances. CER evaluates evidence from existing studies or generates new evidence, in different populations and under specific conditions in which the treatments are actually used. CER does not embrace one research design over another but compares treatments and variations in practice using methods that are most likely to yield widely generalizable results that are directly relevant to clinical practice. Treatments used in transfusion medicine (TM) are among the most widely used in clinical practice, but are among the least well studied. High-quality evidence is lacking for most transfusion practices, with research efforts hampered by regulatory restrictions and ethical barriers. To begin addressing these issues, the National Heart, Lung, and Blood Institute convened a workshop in June 2011 to address the potential role of CER in the generation of high-quality evidence for TM decision making. Workshop goals were to: 1) evaluate the current landscape of clinical research, 2) review the potential application of CER methods to clinical research, 3) assess potential barriers to the use of CER methodology, 4) determine whether pilot or vanguard studies can be used to facilitate planning of future CER research, and 5) consider the need for and delivery of training in CER methods for researchers.

The dilemma of assessment bias in infection control research

Infection control studies often rely on infection endpoints to determine whether interventions are effective. However, many infection outcomes, including those defined by standardized surveillance criteria, involve some subjective judgment for determination. Studies that use unblinded ascertainment of subjective infection endpoints are at risk of assessment bias. Unfortunately, infection control studies have not routinely accounted for assessment bias. To ensure validity, infection control studies should incorporate study design elements to control assessment bias, such as blinded assessment or use of objective outcome measures.

Staphylococcal decolonisation: an effective strategy for prevention of infection?

Staphylococcus aureus decolonisation--treatment to eradicate staphylococcal carriage--is often considered as a measure to prevent S aureus infection. The most common approach to decolonisation has been intranasal application of mupirocin either alone or in combination with antiseptic soaps or systemic antimicrobial agents. Some data support the use of decolonisation in surgical patients colonised with S aureus, particularly in those undergoing cardiothoracic procedures. Although this intervention has been associated with low rates of postoperative S aureus infection, whether overall rates of infection are also decreased is unclear. Patients undergoing chronic haemodialysis or peritoneal dialysis might benefit from decolonisation, although repeated courses of treatment are needed, and the effects are modest. Eradication of meticillin-resistant S aureus (MRSA) carriage has generally been difficult, and the role of decolonisation as an MRSA infection control measure is uncertain. The efficacy of decolonisation of patients with community-associated MRSA has not been established, and the routine use of decolonisation of non-surgical patients is not supported by data.

The methods of comparative effectiveness research

This review describes methods used in comparative effectiveness research (CER). The aim of CER is to improve decisions that affect medical care at the levels of both policy and the individual. The key elements of CER are (a) head-to-head comparisons of active treatments, (b) study populations typical of day-to-day clinical practice, and (c) a focus on evidence to inform care tailored to the characteristics of individual patients. These requirements will stress the principal methods of CER: observational research, randomized trials, and decision analysis. Observational studies are especially vulnerable because they use data that directly reflect the decisions made in usual practice. CER will challenge researchers and policy makers to think deeply about how to extract more actionable information from the vast enterprise of the daily practice of medicine. Fortunately, the methods are largely applicable to research in the public health system, which should therefore benefit from the intense interest in CER.