{"title":"Tutorial on Bayesian Functional Regression Using Stan.","authors":"Ziren Jiang, Ciprian Crainiceanu, Erjia Cui","doi":"10.1002/sim.70265","DOIUrl":"10.1002/sim.70265","url":null,"abstract":"<p><p>This manuscript provides step-by-step instructions for implementing Bayesian functional regression models using Stan. Extensive simulations indicate that the inferential performance of the methods is comparable to that of state-of-the-art frequentist approaches. However, Bayesian approaches allow for more flexible modeling and provide an alternative when frequentist methods are not available or may require additional development. Methods and software are illustrated using the accelerometry data from the National Health and Nutrition Examination Survey (NHANES).</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70265"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12433833/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145065477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Using Confidence Distributions in Final and Interim Analyses for Single-Arm Studies or Platform Trials Consisting of Single-Arm Studies.","authors":"Günter Heimann, Peter Jacko, Tom Parke","doi":"10.1002/sim.70251","DOIUrl":"https://doi.org/10.1002/sim.70251","url":null,"abstract":"<p><p>Confidence distributions are a frequentist alternative to the Bayesian posterior distribution. These confidence distributions have received more attention in the recent past because of their simplicity. In rare diseases, oncology, or in pediatric drug development, single-arm trials, or platform trials consisting of a series of single-arm trials are increasingly being used, both to establish proof-of-concept and to provide pivotal evidence for a marketing application. Often, these single-arm trials are designed as two-stage designs, or they include sequential or continuous monitoring approaches. They are analyzed using standard frequentist, Bayesian, or other methods. In this paper, we describe how to define analysis strategies based on confidence distributions for such single-arm trials or for platform trials that consist of a series of single arm trials. We focus on binary endpoints and show how to define the corresponding decision rules for final and interim analyses and how to derive their operating characteristics exactly, for example, without simulation. Our approach uses predictive probabilities rather than conditional probabilities (as with stochastic curtailment) to define the interim decision rules. It can be applied to platform, basket, and umbrella trials that consist of a series of single-arm trials but also to stand-alone single arm trials.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70251"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145030503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Weighted Trigonometric Regression for Suboptimal Designs in Circadian Transcriptome Studies.","authors":"Michael T Gorczyca, Justice D Sefas","doi":"10.1002/sim.70201","DOIUrl":"10.1002/sim.70201","url":null,"abstract":"<p><p>Circadian transcriptome studies often use trigonometric regression to model gene expression over time. Ideally, protocols in these studies would collect tissue samples at evenly distributed and equally spaced time points over a 24-hour period. This sample collection protocol is known as an equispaced design, which is considered the optimal experimental design for trigonometric regression under multiple statistical criteria. However, implementing equispaced designs in studies involving individuals is logistically challenging, and failure to employ an equispaced design could introduce variability in the statistical power of a hypothesis test relative to a model's phase-shift parameter estimates. This article is motivated by the variability in power for hypothesis testing when tissue samples are not collected under an equispaced design, and considers a weighted trigonometric regression as a remedy. Specifically, the weights for this regression are the normalized reciprocals of estimates derived from a kernel density estimator for sample collection time, which inflates the weight of samples collected at underrepresented time points. A search procedure is also introduced to identify the hyperparameter for kernel density estimation that relates to maximizing the smallest eigenvalue of the Hessian of weighted squared loss, which is motivated by the <math> <semantics><mrow><mi>E</mi></mrow> <annotation>$$ E $$</annotation></semantics> </math> -optimality criterion from experimental design literature. Simulation studies consistently demonstrate that this weighted regression mitigates variability in power for hypothesis tests performed with an estimated model. Illustrations with six circadian transcriptome datasets further indicate that this weighted regression consistently yields larger test statistics than its unweighted counterpart for first-order trigonometric regression, or cosinor regression, which is prevalent in circadian transcriptome studies.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70201"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145065523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Double Negative Control Inference With Some Invalid Negative Control Exposures for Continuous Outcome.","authors":"Qingqing Yang, Jinzhu Jia","doi":"10.1002/sim.70276","DOIUrl":"https://doi.org/10.1002/sim.70276","url":null,"abstract":"<p><p>Negative controls have been increasingly used for causal inference when unmeasured confounding exist. Valid negative control exposures (NCEs) could not causally affect outcome, and valid negative control outcomes (NCOs) are not to be causally affected by exposure. In most observational studies, it is easy to find a valid NCO but NCEs are harder to verify due to the current limited knowledge. Invalid NCEs associated with outcome result in biased estimate of causal effects. However, previous work considering invalid negative controls is very limited. In this paper, we develop a double negative control framework for continuous outcomes in the presence of some invalid NCEs. First, we prove that it is possible to identify causal effects with a known pre-defined valid NCO and a pre-defined set of NCEs without knowing exactly their validity. Furthermore, as long as more than 50% of NCEs are valid, the average causal effect could be consistently estimated. Then we design an <math> <semantics> <mrow><msub><mi>ℓ</mi> <mn>1</mn></msub> </mrow> <annotation>$$ {mathrm{ell}}_1 $$</annotation></semantics> </math> procedure to select valid NCEs. Finally, we give two kinds of double negative control estimators (sisvNCE and naiveNCE-Median) with a guarantee of theoretical estimation performance. Simulation results show that the performance of our method is robust when the number of invalid NCEs does not exceed a certain threshold. Application results indicate that our method has a promising role in public health.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70276"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Futility Analyses for the MCP-Mod Methodology Based on Longitudinal Models.","authors":"Björn Bornkamp, Jie Zhou, Dong Xi, Weihua Cao","doi":"10.1002/sim.70274","DOIUrl":"https://doi.org/10.1002/sim.70274","url":null,"abstract":"<p><p>This article discusses futility analyses for the MCP-Mod methodology. Formulas are derived for calculating predictive and conditional power for MCP-Mod, which also cover the case when longitudinal models are used allowing to utilize incomplete data from patients at interim. A simulation study is conducted to evaluate the repeated sampling properties of the proposed decision rules and to assess the benefit of using a longitudinal versus a completer only model for decision making at interim. The results suggest that the proposed methods perform adequately and a longitudinal analysis outperforms a completer only analysis, particularly when the recruitment speed is higher and the correlation over time is larger. The proposed methodology is illustrated using real data from a dose-finding study for severe uncontrolled asthma.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70274"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145125934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lukas A Widmer, Sebastian Weber, Yunnan Xu, Hans-Jochen Weber
{"title":"Towards Efficient Time-to-Event Dose-Escalation Guidance of Multi-Cycle Cancer Therapies.","authors":"Lukas A Widmer, Sebastian Weber, Yunnan Xu, Hans-Jochen Weber","doi":"10.1002/sim.70229","DOIUrl":"10.1002/sim.70229","url":null,"abstract":"<p><p>Treatment of cancer has rapidly evolved over time in quite dramatic ways, for example, from chemotherapies, targeted therapies to immunotherapies and chimeric antigen receptor T-cells. Nonetheless, the basic design of early phase I trials in oncology still follows predominantly a dose-escalation design. These trials monitor safety over the first treatment cycle to escalate the dose of the investigated drug. However, over time, studying additional factors such as drug combinations and/or variation in the timing of dosing became important as well. Existing designs were continuously enhanced and expanded to account for increased trial complexity. With toxicities occurring at later stages beyond the first cycle and the need to treat patients over multiple cycles, the focus on the first treatment cycle only is becoming a limitation in nowadays multi-cycle treatment therapies. Here, we introduce a multi-cycle time-to-event model (TITE-CLRM: Time-Interval-To-Event Complementary-Loglog Regression Model), allowing guidance of dose-escalation trials studying multi-cycle therapies. The challenge lies in balancing the need to monitor the safety of longer treatment periods with the need to continuously enroll patients safely. The proposed multi-cycle time-to-event model is formulated as an extension to established concepts like the escalation with overdose control principle. The model is motivated by a current drug development project and evaluated in a simulation study.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70229"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145070318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bayesian Adaptive Enrichment Design for Continuous Biomarkers.","authors":"Yue Tu, Yusha Liu, Wendy J Mack, Lindsay A Renfro","doi":"10.1002/sim.70262","DOIUrl":"10.1002/sim.70262","url":null,"abstract":"<p><p>With the advent of precision medicine and targeted therapies in cancer, new challenges in the statistical design of clinical trials have naturally emerged. Most randomized clinical trial designs incorporating predictive biomarkers (those associated with treatment efficacy) assume biomarkers are dichotomous, or dichotomize naturally continuous biomarkers upfront, or find cut points mid-way through the trial to classify patients as biomarker-positive or biomarker-negative. However, these practices ignore or discard information about continuous and possible nonlinear or non-monotone prognostic or predictive effects. In this article, we propose a novel adaptive enrichment trial design to handle continuous biomarkers with any effect shape, including Bayesian marker-adaptive randomization. We demonstrate that this design can correctly make marker-specific trial decisions with high efficiency, resulting in improved performance and patient-centered decisions compared to adaptive cut-point selection approaches without adaptive randomization that further ignore or oversimplify true underlying marker relationships.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70262"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145065496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Fierenz, Mouna Akacha, Norbert Benda, Mahnaz Badpa, Patrick M M Bossuyt, Nandini Dendukuri, Britta Rackow, Antonia Zapf
{"title":"The Estimand Framework in Diagnostic Accuracy Studies.","authors":"Alexander Fierenz, Mouna Akacha, Norbert Benda, Mahnaz Badpa, Patrick M M Bossuyt, Nandini Dendukuri, Britta Rackow, Antonia Zapf","doi":"10.1002/sim.70248","DOIUrl":"10.1002/sim.70248","url":null,"abstract":"<p><p>Diagnostic accuracy studies evaluate how well a diagnostic test can detect or rule out a medical condition. Different events can interfere with the conduct of the test, affecting the test result. Before starting a diagnostic test accuracy study, the clinical question of interest should be precisely defined. Based on that, strategies can be chosen for dealing with the interfering event. We introduce six different strategies for how such events could be handled. We introduce the estimand concept for diagnostic accuracy studies, which consists of the attributes population, target condition, index test, accuracy measure, and the strategies for handling interfering events. The estimand determines which effect is estimated based on the study objective. To bridge the gap between the clinical study objective and the method for the estimation, we illustrate the necessary steps using a fictitious computed tomography scan study. The defined estimand improves the structure of the planning phase, enhances the interdisciplinary exchange, and supports the interpretation based on the study objective.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70248"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12442747/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145076026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fan Li, Jiaqi Tong, Xi Fang, Chao Cheng, Brennan C Kahan, Bingkai Wang
{"title":"Model-Robust Standardization in Cluster-Randomized Trials.","authors":"Fan Li, Jiaqi Tong, Xi Fang, Chao Cheng, Brennan C Kahan, Bingkai Wang","doi":"10.1002/sim.70270","DOIUrl":"https://doi.org/10.1002/sim.70270","url":null,"abstract":"<p><p>In cluster-randomized trials, generalized linear mixed models and generalized estimating equations have conventionally been the default analytic methods for estimating the average treatment effect as routine practice. However, recent studies have demonstrated that their treatment effect coefficient estimators may correspond to ambiguous estimands when the models are misspecified or when there exist informative cluster sizes. In this article, we present a unified approach that standardizes output from a given regression model to ensure estimand-aligned inference for the treatment effect parameters in cluster-randomized trials. We introduce estimators for both the cluster-average and the individual-average treatment effects (marginal estimands) that are always consistent regardless of whether the specified working regression models align with the unknown data generating process. We further explore the use of a deletion-based jackknife variance estimator for inference. The development of our approach also motivates a natural test for informative cluster size. Extensive simulation experiments are designed to demonstrate the advantage of the proposed estimators under a variety of scenarios. The proposed model-robust standardization methods are implemented in the MRStdCRT R package.</p>","PeriodicalId":21879,"journal":{"name":"Statistics in Medicine","volume":"44 20-22","pages":"e70270"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145087326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}