In a multi-arm trial with predefined subgroups for each intervention to target, it is often desirable to enrich assignment to an intervention by enrolling more biomarker-positive participants to the intervention. We describe how to implement a biased coin design to achieve desired allocation ratios among interventions and between the number of biomarker-positive and biomarker-negative participants assigned to each intervention. We illustrate the proposed method with the randomization algorithm implemented in the Precision Interventions for Severe and/or Exacerbation-prone Asthma (PrecISE) trial.
View Article and Find Full Text PDFA randomized, double-blind, placebo-controlled clinical trial was conducted to investigate the efficacy of infliximab, abatacept, and cenicriviroc in treating patients hospitalized with COVID-19. The patient's clinical status was assessed daily on an 8-point ordinal scale. We evaluated the totality of evidence on the efficacy of the 3 immunomodulators by considering all possible changes in the clinical status of each patient over time.
View Article and Find Full Text PDFAsthma is a heterogeneous disease, with multiple underlying inflammatory pathways and structural airway abnormalities that impact disease persistence and severity. Recent progress has been made in developing targeted asthma therapeutics, especially for subjects with eosinophilic asthma. However, there is an unmet need for new approaches to treat patients with severe and exacerbation-prone asthma, who contribute disproportionately to disease burden.
View Article and Find Full Text PDFAcute respiratory distress syndrome (ARDS) is a heterogeneous clinical syndrome. Understanding of the complex pathways involved in lung injury pathogenesis, resolution, and repair has grown considerably in recent decades. Nevertheless, to date, only therapies targeting ventilation-induced lung injury have consistently proven beneficial, and despite these gains, ARDS morbidity and mortality remain high.
View Article and Find Full Text PDFSevere asthma accounts for almost half the cost associated with asthma. Severe asthma is driven by heterogeneous molecular mechanisms. Conventional clinical trial design often lacks the power and efficiency to target subgroups with specific pathobiological mechanisms.
View Article and Find Full Text PDFThe Precision Interventions for Severe and/or Exacerbation-prone Asthma (PrecISE) study is an adaptive platform trial designed to investigate novel interventions to severe asthma. The study is conducted under a master protocol and utilizes a crossover design with each participant receiving up to five interventions and at least one placebo. Treatment assignments are based on the patients' biomarker profiles and precision health methods are incorporated into the interim and final analyses.
View Article and Find Full Text PDFThe issuance of a report in 2010 by the National Research Council (NRC) of the National Academy of Sciences entitled 'The Prevention and Treatment of Missing Data in Clinical Trials,' commissioned by the US Food and Drug Administration, had an immediate impact on the way that statisticians and clinical researchers in both industry and regulatory agencies think about the missing data problem. We believe that there is currently great potential to improve study quality and interpretability-by reducing the amount of missing data through changes in trial design and conduct and by planning and conducting analyses that better account for the missing information. Here, we describe our view on some of the recommendations in the report and suggest ways in which these recommendations can be incorporated into new or ongoing clinical trials in order to improve their chance of success.
View Article and Find Full Text PDFAnn Epidemiol
November 2014
Purpose: To describe prevalence and relationships to cardiovascular morbidity of depression, anxiety, and medication use among Hispanic/Latinos of different ethnic backgrounds.
Methods: Cross-sectional analysis of 15,864 men and women aged 18 to 74 years in the population-based Hispanic Community Health Study/Study of Latinos. Depressive and anxiety symptoms were assessed with shortened Center for Epidemiological Studies Depression Scale and Spielberger Trait Anxiety Scale.
Objective: We examine differences in prevalence of diabetes and rates of awareness and control among adults from diverse Hispanic/Latino backgrounds in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).
Research Design And Methods: The HCHS/SOL, a prospective, multicenter, population-based study, enrolled from four U.S.
Background: The prevention and control of hypertension is an essential component for reducing the burden of cardiovascular diseases. Here we describe the prevalence of hypertension in diverse Hispanic/Latino background groups and describe the proportion who are aware of their diagnosis, receiving treatment, and having their hypertension under control.
Methods: The Hispanic Community Health Study/Study of Latinos is a longitudinal cohort study of 16,415 Hispanics/Latinos, aged 18-74 years from 4 US communities (Bronx, NY; Chicago, IL; Miami, FL; and San Diego, CA).
The number of statistical challenges facing regulators remains high, as does the importance of statistical thinking in the regulatory decision-making process. Statisticians in the Office of Biostatistics at the US Food and Drug Administration review hundreds of new drug and therapeutic biologic applications each year and advise sponsors on protocols numbering in the thousands. In addition to remaining up to date on the newest statistical methods, statisticians are often called upon for innovative approaches to difficult regulatory problems.
View Article and Find Full Text PDFSubpopulations and Intermediate Outcomes in COPD Study (SPIROMICS) is a multicentre observational study of chronic obstructive pulmonary disease (COPD) designed to guide future development of therapies for COPD by providing robust criteria for subclassifying COPD participants into groups most likely to benefit from a given therapy during a clinical trial, and identifying biomarkers/phenotypes that can be used as intermediate outcomes to reliably predict clinical benefit during therapeutic trials. The goal is to enrol 3200 participants in four strata. Participants undergo a baseline visit and three annual follow-up examinations, with quarterly telephone calls.
View Article and Find Full Text PDFRationale: Several studies suggest that nasal nitric oxide (nNO) measurement could be a test for primary ciliary dyskinesia (PCD), but the procedure and interpretation have not been standardized.
Objectives: To use a standard protocol for measuring nNO to establish a disease-specific cutoff value at one site, and then validate at six other sites.
Methods: At the lead site, nNO was prospectively measured in individuals later confirmed to have PCD by ciliary ultrastructural defects (n = 143) or DNAH11 mutations (n = 6); and in 78 healthy and 146 disease control subjects, including individuals with asthma (n = 37), cystic fibrosis (n = 77), and chronic obstructive pulmonary disease (n = 32).
In the absence of placebo-controlled trials, determining the non-inferiority (NI) margin for comparing an experimental treatment with an active comparator is based on carefully selected well-controlled historical clinical trials. With this approach, information on the effect of the active comparator from other sources including observational studies and early phase trials is usually ignored because of the need to maintain active comparator effect across trials. This may lead to conservative estimates of the margin that translate into larger sample-size requirements for the design and subsequent frequentist analysis, longer trial durations, and higher drug development costs.
View Article and Find Full Text PDFObjective: To add to the evidence on comparative long-term effects of insulin analog glargine versus human NPH insulin on the risk for cancer.
Research Design And Methods: We identified cohorts of initiators of glargine and human NPH without an insulin prescription during the prior 19 months among patients covered by the Inovalon Medical Outcomes Research for Effectiveness and Economics Registry (MORE2 Registry) between January 2003 and December 2010. Patients were required to have a second prescription of the same insulin within 180 days and to be free of cancer.
We develop a simple statistic for comparing rates of rare adverse events between treatment groups in postmarketing safety studies where the events have uncertain status. In this setting, the statistic is asymptotically equivalent to the logrank statistic, but the limiting distribution has Poisson and binomial components instead of being Gaussian. We develop two new procedures for computing critical values: a Gaussian approximation and a parametric bootstrap.
View Article and Find Full Text PDFWe develop a simple statistic for comparing rates of rare adverse events between treatment groups in postmarketing safety studies where the events have uncertain status. In this setting, the statistic is asymptotically equivalent to the logrank statistic, but the limiting distribution has Poisson and binomial components instead of being Gaussian. We develop two new procedures for computing critical values, a Gaussian approximation and a parametric bootstrap.
View Article and Find Full Text PDFBackground: In response to the Agency for Healthcare Research and Quality statement questioning the usefulness of “screening spirometry,” the National Heart, Lung, and Blood Institute and the COPD Foundation held a consensus conference in June 2008 to establish a procedure to detect cases of COPD in the general population. Conference participants developed a three-stage approach, using a brief questionnaire, peak flow measurement with a pocket spirometer, and diagnostic quality spirometry. The overall objective of this study was to examine the usefulness of a simple questionnaire and peak flow measurement in screening for COPD in a self-selected population.
View Article and Find Full Text PDFObjective: The authors conducted a multisite randomized controlled trial examining the strategy of switching from olanzapine, quetiapine, or risperidone to aripiprazole to ameliorate metabolic risk factors for cardiovascular disease.
Method: Patients with schizophrenia or schizoaffective disorder with a body mass index ≥ 27 and non-high-density lipoprotein (non-HDL) cholesterol ≥ 130 mg/dl who were on a stable treatment dosage of olanzapine, quetiapine, or risperidone were randomly assigned to switch to ari-piprazole (N=109) for 24 weeks or stay on their current medication (N=106). All participants were enrolled in a behaviorally oriented diet and exercise program.
Background: Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and interchange of hospital-associated strains carrying the staphylococcal chromosomal cassette mec-II (SCCmec-II) with those in the community (SCCmec-IV) has increased. This study assesses the impact of MRSA and different MRSA types on clinical outcomes, medication use, and antibiotic sensitivities.
Methods: MRSA isolates from CF patients at our center were typed by SCCmec- and pv(l) status.
Purpose: The Hispanic Community Health Study (HCHS)/Study of Latinos (SOL) is a multicenter, community-based cohort study of Hispanic/Latino adults in the United States. A diverse participant sample is required that is both representative of the target population and likely to remain engaged throughout follow-up. The choice of sample design, its rationale, and benefits and challenges of design decisions are described in this study.
View Article and Find Full Text PDFBackground: The goal of public health research often involves estimating clinical outcomes for a broad target population. The gold standard for the basis of such inference is a nationally representative survey that includes a clinical component. The cost of this gold standard can be prohibitive, and alternative approaches are needed.
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