Publications by authors named "Alt E"

Article Synopsis
  • The text discusses the challenges of using existing informative priors from historical data in statistical analysis, as they often apply blanket discounting that may not fit all participants.
  • It introduces a new method called the latent exchangeability prior (LEAP), which classifies historical data into exchangeable and non-exchangeable groups to better identify relevant subjects.
  • The effectiveness of LEAP is compared to other methods through simulations, and a practical example is given by applying it to enhance a control group in a clinical trial for plaque psoriasis.
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The discussions of our paper provide insights into the practical considerations of the latent exchangeability prior while also highlighting further extensions. In this rejoinder, we briefly summarize the discussions and provide comments.

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Article Synopsis
  • The study focuses on understanding the risk of spontaneous abortion (SAB) and termination using Medicaid healthcare data, requiring accurate algorithms to estimate gestational age (GA).
  • Researchers created a hierarchical algorithm to classify pregnancy outcomes and developed three approaches to estimate GA: using median GA, random distribution, and regression models.
  • The best-performing approach utilized random forest models and achieved 58.0% accuracy for SAB and 66.3% for terminations within 2 weeks of the gold standard, highlighting the feasibility of studying these outcomes despite some misclassification issues.
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Despite the critical roles of nondominant perforators, choke vessels, and direct and indirect linking vessels in flap vascularity, current models of flap perfusion focus on a primary large caliber perforators. The delay phenomenon, microvascularization, neovascularization, and vascular evolution, which depend on smaller caliber vessels, remain unaccounted for. We propose that the "circulasome" consists of the sum of the entire vascular components of a given region, such that the region is supplied by a primary supplying vessel.

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Background: Topical nitrates have demonstrated efficacy in improving flap perfusion. However, evidence for nontopical nitrates in modulation of flap perfusion dynamics has yet to be consolidated. Here, we review evidence regarding the use of intravascular, sublingual, and oral nitrates in modulating flap perfusion.

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Low volumetric retention limits the utility of fat grafting. Although inclusion of stem cells and platelet-rich plasma have been proposed to enhance graft retention, accumulating evidence has failed to show a clear benefit. Here, we propose a strategy to pharmacologically enhance stemness of stem and progenitor cell populations in fat grafts to promote increased volume retention and tissue health.

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There are many Bayesian design methods allowing for the incorporation of historical data for sample size determination (SSD) in situations where the outcome in the historical data is the same as the outcome of a new study. However, there is a dearth of methods supporting the incorporation of data from a previously completed clinical trial that investigated the same or similar treatment as the new trial but had a primary outcome that is different. We propose a simulation-based Bayesian SSD framework using the partial-borrowing scale transformed power prior (straPP).

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Background: Type 2 muscle flaps are characterized by major and minor pedicles, such that the minor pedicle is unreliable, and the major pedicle is a requirement for the success of the flap. The role of the minor pedicle, beyond the decreased caliber and decreased vascular territory in comparison to the major pedicle, is poorly understood. We sought to model the fluid dynamics of a model flap containing a major and minor pedicle to understand differences between the pedicles and the implications on perfusion.

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Postmarket drug safety database like vaccine adverse event reporting system (VAERS) collect thousands of spontaneous reports annually, with each report recording occurrences of any adverse events (AEs) and use of vaccines. We hope to identify signal vaccine-AE pairs, for which certain vaccines are statistically associated with certain adverse events (AE), using such data. Thus, the outcomes of interest are multiple AEs, which are binary outcomes and could be correlated because they might share certain latent factors; and the primary covariates are vaccines.

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Symptomatic, partial-thickness rotator cuff tears (sPTRCT) are problematic. This study tested the hypothesis that management of sPTRCT with injection of fresh, uncultured, unmodified, autologous, adipose-derived regenerative cells (UA-ADRCs) is safe and more effective than injection of corticosteroid even in the long run. To this end, subjects who had completed a former randomized controlled trial were enrolled in the present study.

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We provide commentary on the paper by Willi Maurer, Frank Bretz, and Xiaolei Xun entitled, "Optimal test procedures for multiple hypotheses controlling for the familywise expected loss." The authors provide an excellent discussion of the multiplicity problem in clinical trials and propose a novel approach based on a decision-theoretic framework that incorporates loss functions that can vary across multiple hypotheses in a family. We provide some considerations for the practical use of the authors' proposed methods as well as some alternative methods that may also be of interest in this setting.

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Arrhythmias of the heart are currently treated by implanting electronic pacemakers and defibrillators. Unmodified adipose tissue-derived stem cells (ASCs) have the potential to differentiate into all three germ layers but have not yet been tested for the generation of pacemaker and Purkinje cells. We investigated if-based on overexpression of dominant conduction cell-specific genes in ASCs-biological pacemaker cells could be induced.

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Trial results may not be generalizable to target populations treated in clinical practice with different distributions of baseline characteristics that modify the treatment effect. We used outcome models developed with trial data to predict treatment effects in Medicare populations. We used data from the Randomized Evaluation of Long-Term Anticoagulation Therapy trial (RE-LY), which investigated the effect of dabigatran vs.

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Background: Chronic back pain due to facet joint syndrome is a common and debilitating condition. Advances in regenerative medicine have shown that autologous unmodified adipose tissue-derived regenerative cells (ADRC) provide several beneficial effects. These regenerative cells can differentiate into various tissues and exhibit a strong anti-inflammatory potential.

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We established wastewater surveillance of SARS-CoV-2 in a small, residential, urban college as part of an integrated public health response during the COVID-19 pandemic. Students returned to campus in spring 2021. During the semester, students were required to perform nasal PCR tests twice weekly.

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Background: Inclusion of evidence-based behavior change techniques (e.g., self-monitoring) in mobile health apps has the potential to promote adherence to inflammatory bowel disease treatment.

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There has been increased interest in the design and analysis of studies consisting of multiple response variables of mixed types. For example, in clinical trials, it is desirable to establish efficacy for a treatment effect in primary and secondary outcomes. In this article, we develop Bayesian approaches for hypothesis testing and study planning for data consisting of multiple response variables of mixed types with covariates.

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Background: Severe hypoglycemia is associated with adverse clinical outcomes. We evaluated the risk of severe hypoglycemia in older adults initiating newer glucose-lowering medications overall and across strata of known indicators of high hypoglycemia risk.

Methods: We conducted a comparative-effectiveness cohort study of older adults aged >65 years with type 2 diabetes initiating sodium-glucose cotransporter 2 inhibitors (SGLT2i) versus dipeptidyl peptidase-4 inhibitors (DPP-4i) or SGLT2i versus glucagon-like peptide-1 receptor agonists (GLP-1RA) using Medicare claims (3/2013-12/2018) and Medicare-linked-electronic health records.

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Importance: Sodium-glucose cotransporter 2 inhibitor (SGLT2i) therapy has been associated with cardiovascular benefits and a few adverse events; however, whether the comparative effectiveness and safety profiles vary with differences in baseline hemoglobin A1c (HbA1c) levels is unknown.

Objective: To compare cardiovascular effectiveness and safety of treatment with SGLT2i vs dipeptidyl peptidase 4 inhibitor (DPP-4i) in adults with type 2 diabetes (T2D) (1) overall and (2) at varying baseline HbA1c levels.

Design, Setting, And Participants: A new-user comparative effectiveness and safety research study was conducted among 144 614 commercially insured adults, initiating treatment with SGLT2i or DPP-4i and with a recorded T2D diagnosis at baseline and at least 1 HbA1c laboratory result recorded within 3 months before treatment initiation.

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Uncultured, unmodified, autologous, adipose-derived regenerative cells (UA-ADRCs) are a safe and effective treatment option for various musculoskeletal pathologies. However, it is unknown whether the composition of the final cell suspension systematically varies with the subject's individual age, sex, body mass index and ethnicity. UA-ADRCs were isolated from lipoaspirate from = 232 subjects undergoing elective lipoplasty using the Transpose RT system (InGeneron, Inc.

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Cellular stress, arising from accumulation of unfolded proteins, occurs frequently in rapidly proliferating cancer cells. This cellular stress, in turn, activates the unfolded protein response (UPR), an interconnected set of signal transduction pathways that alleviate the proteostatic stress. The UPR is implicated in cancer cell survival and proliferation through upregulation of pro-tumorigenic pathways that ultimately promote malignant metabolism and neoangiogenesis.

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We develop the scale transformed power prior for settings where historical and current data involve different data types, such as binary and continuous data. This situation arises often in clinical trials, for example, when historical data involve binary responses and the current data involve some other type of continuous or discrete outcome. The power prior, proposed by Ibrahim and Chen, does not address the issue of different data types.

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Background: COVID-19 represents one of the most significant medical problems of our time.

Aims: This study is focused on the question whether patients with inflammatory bowel disease (IBD) who receive immunotherapies are more vulnerable to respiratory tract infections and SARS-CoV-2 infections in comparison to medical staff, as a cohort with an increased infection risk, and to the general population in a COVID-19 hotspot.

Methods: We analysed data regarding respiratory tract infections that were collected in our IBD registry and compared them with corresponding data from medical employees in our associated Isarklinikum hospital and from the healthy general population in Munich, Germany, over the same time frame in April and June 2020.

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Increased vascularization, also known as neoangiogenesis, plays a major role in many cancers, including glioblastoma multiforme (GBM), by contributing to their aggressive growth and metastasis. Although anti-angiogenic therapies provide some clinical improvement, they fail to significantly improve the overall survival of GBM patients. Since various pro-angiogenic mediators drive GBM, we hypothesized that identifying targetable genes that broadly inhibit multiple pro-angiogenic mediators will significantly promote favorable outcomes.

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