BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf072
Mihai Giurcanu, Theodore Karrison
{"title":"Non-parametric estimators of hazard ratios for comparing two survival curves.","authors":"Mihai Giurcanu, Theodore Karrison","doi":"10.1093/biomtc/ujaf072","DOIUrl":"10.1093/biomtc/ujaf072","url":null,"abstract":"<p><p>We propose non-parametric estimators of the hazard ratio for comparing two survival curves using estimating equations defined in terms of group-specific cumulative hazard functions. We first describe the methods and their asymptotic properties in the case of a constant hazard ratio. We then extend the methods and the asymptotic results when the hazard ratio is time dependent and well approximated by a locally constant function. We propose a method to select the change points in the local hazard ratios. We extend the methods to stratified estimators and propose tests for heterogeneity of constant and time-dependent hazard ratios across strata. In a simulation study, we describe the finite sample properties of the proposed estimators and compare their performance with the Cox partial maximum likelihood estimator (MLE) in terms of efficiency and accuracy of coverage rates. An example is provided to illustrate an application of the proposed methods in practice.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144332419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf069
Nina Deliu, Sofia S Villar
{"title":"On the finite-sample and asymptotic error control of a randomization-probability test for response-adaptive clinical trials.","authors":"Nina Deliu, Sofia S Villar","doi":"10.1093/biomtc/ujaf069","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf069","url":null,"abstract":"<p><p>It is now commonly known that using response-adaptive designs for data collection offers great potential in terms of optimizing expected outcomes, but poses multiple challenges for inferential goals. In many settings, such as phase-II or confirmatory clinical trials, a main barrier to their practical use is the lack of type-I error guarantees and/or power efficiency, especially in finite samples. This work addresses this gap. Specifically, focusing on a novel test statistic defined on the randomization probabilities of the (randomized) adaptive design, we derive its finite-sample and asymptotic guarantees. Further theoretical properties are evaluated for Thompson sampling, a Bayesian response-adaptive design that is commonly used both in clinical applications and beyond (eg, recommendation systems or mobile health). The frequentist error control advantages of the proposed approach-also able to preserve expected outcome optimalities-are illustrated in a real-world phase-II oncology trial and in simulation experiments.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144282250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf080
Eun Jeong Oh, Seungjun Ahn, Tristan Tham, Min Qian
{"title":"Leveraging two-phase data for improved prediction of survival outcomes with application to nasopharyngeal cancer.","authors":"Eun Jeong Oh, Seungjun Ahn, Tristan Tham, Min Qian","doi":"10.1093/biomtc/ujaf080","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf080","url":null,"abstract":"<p><p>Accurate survival predicting models are essential for improving targeted cancer therapies and clinical care among cancer patients. In this article, we investigate and develop a method to improve predictions of survival in cancer by leveraging two-phase data with expert knowledge and prognostic index. Our work is motivated by two-phase data in nasopharyngeal cancer (NPC), where traditional covariates are readily available for all subjects, but the primary viral factor, human papillomavirus (HPV), is substantially missing. To address this challenge, we propose an expert-guided method that incorporates prognostic index based on the observed covariates and clinical importance of key factors. The proposed method makes efficient use of available data, not simply discarding patients with unknown HPV status. We apply the proposed method and evaluate it against other existing approaches through a series of simulation studies and real data example of NPC patients. Under various settings, the proposed method consistently outperforms competing methods in terms of c-index, calibration slope, and integrated Brier score. By efficiently leveraging two-phase data, the model provides a more accurate and reliable predictive ability of survival models.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144494095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf058
Wilson J Wright, Mevin B Hooten
{"title":"Rejoinder to the discussion on \"Continuous-space occupancy models\".","authors":"Wilson J Wright, Mevin B Hooten","doi":"10.1093/biomtc/ujaf058","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf058","url":null,"abstract":"<p><p>The discussions of our paper consider some assumptions of continuous-space occupancy models, alternative approaches, and directions for future research. In this short rejoinder, we expand on some of these ideas and provide additional comments.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143967242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Discussion on \"Continuous-space occupancy models\" by Wilson J. Wright and Mevin B. Hooten.","authors":"Léa Pautrel, Marie-Pierre Etienne, Olivier Gimenez","doi":"10.1093/biomtc/ujaf057","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf057","url":null,"abstract":"","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143964284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf056
Jeffrey W Doser, Krishna Pacifici
{"title":"Discussion on \"Continuous-space occupancy models\" by Wilson J. Wright and Mevin B. Hooten.","authors":"Jeffrey W Doser, Krishna Pacifici","doi":"10.1093/biomtc/ujaf056","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf056","url":null,"abstract":"","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143953086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf034
Danning Li, Lingzhou Xue, Haoyi Yang, Xiufan Yu
{"title":"Power-enhanced two-sample mean tests for high-dimensional microbiome compositional data.","authors":"Danning Li, Lingzhou Xue, Haoyi Yang, Xiufan Yu","doi":"10.1093/biomtc/ujaf034","DOIUrl":"10.1093/biomtc/ujaf034","url":null,"abstract":"<p><p>Testing differences in mean vectors is a fundamental task in the analysis of high-dimensional microbiome compositional data. Existing methods may suffer from low power if the underlying signal pattern is in a situation that does not favor the deployed test. In this work, we develop 2-sample power-enhanced mean tests for high-dimensional compositional data based on the combination of $P$-values, which integrates strengths from 2 popular types of tests: the maximum-type test and the quadratic-type test. We provide rigorous theoretical guarantees on the proposed tests, showing accurate Type-I error rate control and enhanced testing power. Our method boosts the testing power toward a broader alternative space, which yields robust performance across a wide range of signal pattern settings. Our methodology and theory also contribute to the literature on power enhancement and Gaussian approximation for high-dimensional hypothesis testing. We demonstrate the performance of our method on both simulated data and real-world microbiome data, showing that our proposed approach improves the testing power substantially compared to existing methods.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11962435/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf061
Ante Bing, Donna Spiegelman, Daniel Nevo, Judith J Lok
{"title":"Learn-As-you-GO (LAGO) trials: optimizing treatments and preventing trial failure through ongoing learning.","authors":"Ante Bing, Donna Spiegelman, Daniel Nevo, Judith J Lok","doi":"10.1093/biomtc/ujaf061","DOIUrl":"10.1093/biomtc/ujaf061","url":null,"abstract":"<p><p>It is well known that changing the intervention package while a trial is ongoing does not lead to valid inference using standard statistical methods. However, it is often necessary to adapt, tailor, or tweak a complex intervention package in public health implementation trials, especially when the intervention package does not have the desired effect. This article presents conditions under which the resulting analyses remain valid even when the intervention package is adapted while a trial is ongoing. Our results on such Learn-As-you-GO (LAGO) trials extend the theory of LAGO for binary outcomes following a logistic regression model to LAGO for continuous outcomes under flexible conditional mean models. Because the mathematical methods for binary outcomes do not apply to continuous outcomes, the theory presented in this paper is entirely new. We derive point and interval estimators of the intervention effects and ensure the validity of hypothesis tests for an overall intervention effect. We develop a confidence set for the optimal intervention package, which achieves a pre-specified mean outcome while minimizing cost, and confidence bands for the mean outcome under all intervention package compositions. This work will be useful for the design and analysis of large-scale intervention trials where the intervention package is adapted, tailored, or tweaked while the trial is ongoing.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12099308/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf060
Daiqing Wu, Molei Liu
{"title":"Robust and efficient semi-supervised learning for Ising model.","authors":"Daiqing Wu, Molei Liu","doi":"10.1093/biomtc/ujaf060","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf060","url":null,"abstract":"<p><p>In biomedical studies, it is often desirable to characterize the interactive mode of multiple disease outcomes beyond their marginal risk. Ising model is one of the most popular choices serving this purpose. Nevertheless, learning efficiency of Ising models can be impeded by the scarcity of accurate disease labels, which is a prominent problem in contemporary studies driven by electronic health records (EHRs). Semi-supervised learning (SSL) leverages the large unlabeled sample with auxiliary EHR features to assist the learning with labeled data only and is a potential solution to this issue. In this paper, we develop a novel SSL method for efficient inference of Ising model. Our method first models the outcomes against the auxiliary features, then uses it to project the score function of the supervised estimator onto the EHR features, and incorporates the unlabeled sample to augment the supervised estimator for variance reduction without introducing bias. For the key step of conditional modeling, we propose strategies that can effectively leverage the auxiliary EHR information while maintaining moderate model complexity. In addition, we introduce approaches including intrinsic efficient updates and ensemble, to overcome the potential misspecification of the conditional model that may cause efficiency loss. Our method is justified by asymptotic theory and shown to outperform existing SSL methods through simulation studies. We also illustrate its utility in a real example about several key phenotypes related to frequent intensive care unit (ICU) admission on MIMIC-III data set.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BiometricsPub Date : 2025-04-02DOI: 10.1093/biomtc/ujaf044
Seonghun Cho, Jae Kwang Kim, Yumou Qiu
{"title":"Multiple bias calibration for valid statistical inference under nonignorable nonresponse.","authors":"Seonghun Cho, Jae Kwang Kim, Yumou Qiu","doi":"10.1093/biomtc/ujaf044","DOIUrl":"https://doi.org/10.1093/biomtc/ujaf044","url":null,"abstract":"<p><p>Valid statistical inference is notoriously challenging when the sample is subject to nonresponse bias. We approach this difficult problem by employing multiple candidate models for the propensity score (PS) function combined with empirical likelihood. By incorporating multiple working PS models into the internal bias calibration constraint in the empirical likelihood, the selection bias can be safely eliminated as long as the working PS models contain the true model and their expectations are equal to the true missing rate. The bias calibration constraint for the multiple PS models is called the multiple bias calibration. The study delves into the asymptotic properties of the proposed method and provides a comparative analysis through limited simulation studies against existing methods. To illustrate practical implementation, we present a real data analysis on body fat percentage using the National Health and Nutrition Examination Survey dataset.</p>","PeriodicalId":8930,"journal":{"name":"Biometrics","volume":"81 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143969406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}