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Isotonic Estimation of additive Covariate Effects Under Proportional Hazard models

STATISTICS IN BIOSCIENCES 2024年 1-27页

作者： Chung, Yunro Ivanova, Anastasia Fine, Jason Coll Hlth Solut 550 N 3rd St Phoenix AZ 85004 USA Biodesign Inst Ctr Personalized Diagnost 1001 South McAllister Ave Tempe AZ 10587 USA Univ North Carolina Chapel Hill Dept Biostat 135 Dauer Dr Chapel Hill NC 27599 USA Univ Pittsburgh Dept Stat 230 S Bouquet St Pittsburgh PA 15260 USA

In this paper, we generalize the isotonic proportional hazards model to include multiple continuous covariates with an unspecified baseline hazard function where the effect of the covariate on a failure rate is monotone but otherwise unspecified. In particular, we study the additive isotonic structure of multiple covariates, assuming the monotonic effects of the covariates are separated and linearly added to the semiparametric proportional hazards model. We propose an efficient computation by implementing the pseudo iterative convex minorant algorithm in the cycling algorithm. The algorithm is extended to a model with multiple time-dependent covariates. In simulation studies, our proposed method shows a decrease in bias and variance as the sample size increases. Additionally, we will demonstrate the practical utility of our methodology using data from a cardiovascular study.

关键词： Constrained estimation generalized additive model Nonparametric maximum likelihood estimator Shape-restricted analysis Survival analysis

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Oxygen saturation centiles in healthy preterm neonates in the first 10 min of life: a prospective observational study

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EUROPEAN JOURNAL OF PEDIATRICS 2023年第4期182卷 1637-1645页

作者： Chandra, Purna Sundaram, Venkataseshan Kumar, Praveen Postgrad Inst Med Educ & Res Dept Pediat Div Neonatol Chandigarh 160012 India

Current oxygen saturation targets in delivery room given by Neonatal Resuscitation Program (NRP) are essentially derived from term neonates. This prospective observational study was conducted in a level-III neonatal unit in preterm neonates (< 37 weeks) who did not receive resuscitation or supplemental oxygen to create centile charts for pre-ductal oxygen saturations using robust statistical modelling methods. Pre-ductal oxygen saturations (SPO2) were recorded from birth till 10 min of age using current generation Masimo pulse oximeters. Centile charts were created by generalized additive models. The change in oxygen saturations over time across subjects was modelled as a Bayesian linear regression mixed-effects model after including 'a priori' covariates. Oxygen saturation data was analysed in 180 subjects with mean gestation of 34 +/- 2 weeks. Mean (SD) time to first SPO2 was 167 +/- 77 s. The median time to SPO2 of > 90% was 310 s (IQR: 235-400). Time to > 90% SPO2 was shorter in (a) 34-36 weeks compared to < 34 weeks (290 vs 340;p = 0.03) and (b) vaginally delivered compared to caesarean-section born neonates (300 vs 360;p = 0.2).Conclusions: Oxygen saturations in first 10 min of age in healthy preterm neonates are significantly higher than the targets proposed by the NRP-2020. Larger preterm neonates and those born through vaginal route attained a preductal saturation of > 90% sooner.

关键词： Preterm Neonate Oxygen saturation Delivery room Centile charts generalized additive model

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Heterogeneity in route choice during peak hours: Implications on travel demand management

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TRAVEL BEHAVIOUR AND SOCIETY 2025年 38卷

作者： Deng, Jihao Li, Tianhao Yang, Zhiwei Yuan, Quan Chen, Xiaohong Univ Toronto Dept Civil & Mineral Engn 35 St George St Toronto ON M5S 1A4 Canada Minist Educ Key Lab Rd & Traff Engn 4800 Caoan Rd Shanghai 201804 Peoples R China Hong Kong Univ Sci & Technol Dept Civil & Environm Engn 1 Du Xue Rd Guangzhou 511458 Peoples R China

Traffic congestion has imposed considerable economic expenses and environmental challenges on metropolitan areas. Consequently, cities have implemented Travel Demand Management (TDM) strategies to mitigate this issue during peak hours. Although studies have investigated how individuals make decisions during commuting in response to TDM incentives, there is limited research on differences in route choices between trips to and from work, making the policies less effective. This study aims to fill this gap by using trajectory data from over 3,000 vehicles and examines the impacts of time-varying features, route characteristics, and built environment factors on route variability. Results indicate that factors such as expressway proportion, travel cost, and road density at the origin and destination locations have similar effects on route variability during morning and evening commuting. However, departure time, travel distance, and the number of traffic lights significantly differ in impacting route variability between the two scenarios. This study provides a foundation for optimizing route choices and alleviating traffic emissions during peak hours through advanced TDM measures. With more detailed and deliberate policies, citizens can enjoy urban mobility within a well-organized road network in a more sustainable and efficient way.

关键词： Trajectory data Route variability generalized additive model XGBoost Travel demand management

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Classification and severity progression measure of COVID-19 patients using pairs of multi-omic factors

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JOURNAL OF APPLIED STATISTICS 2023年第11-12期50卷 2473-2503页

作者： Chen, Teng Polak, Pawel Uryasev, Stanislav SUNY Stony Brook Dept Appl Math & Stat Math TowerRoom B-148 Stony Brook NY 11794 USA

Early detection and effective treatment of severe COVID-19 patients remain two major challenges during the current pandemic. Analysis of molecular changes in blood samples of severe patients is one of the promising approaches to this problem. From thousands of proteomic, metabolomic, lipidomic, and transcriptomic biomarkers selected in other research, we identify several pairs of biomarkers that after additional nonlinear spline transformation are highly effective in classifying and predicting severe COVID-19 cases. The performance of these pairs is evaluated in-sample, in a cross-validation exercise, and in an out-of-sample analysis on two independent datasets. We further improve our classifier by identifying complementary pairs using hierarchical clustering. In a result, we achieve 96-98% AUC on the validation data. Our findings can help medical experts to identify small groups of biomarkers that after nonlinear transformation can be used to construct a cost-effective test for patient screening and prediction of severity progression.

关键词： COVID-19 cluster analysis generalized additive model nonparametric logistic regression spline interpolation

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Shelf break exchange processes influence the availability of the northern shortfin squid, Illex illecebrosus, in the Northwest Atlantic

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FISHERIES OCEANOGRAPHY 2023年第5期32卷 461-478页

作者： Salois, Sarah L. L. Hyde, Kimberly J. W. Silver, Adrienne Lowman, Brooke A. A. Gangopadhyay, Avijit Gawarkiewicz, Glen Mercer, Anna J. M. Manderson, John P. P. Gaichas, Sarah K. K. Hocking, Daniel J. J. Galuardi, Benjamin Jones, Andrew W. W. Kaelin, Jeff DiDomenico, Greg Almeida, Katie Bright, Bill Lapp, Meghan NOAA Northeast Fisheries Sci Ctr 28 Tarzwell Dr Narragansett RI 02882 USA Woods Hole Oceanog Inst Dept Phys Oceanog Woods Hole MA 02543 USA Virginia Marine Resources Commiss 380 Fenwick Rd Ft Monroe VA 23651 USA Univ Massachusetts Dartmouth Sch Marine Sci & Technol 836 South Rodney French Blvd New Bedford MA 02744 USA OpenOcean Res POB 594 Blue Hill ME 04614 USA NOAA Northeast Fisheries Sci Ctr 166 Water St Woods Hole MA 02543 USA NOAA Natl Marine Fisheries Serv Greater Atlantic Reg Fisheries Off 55 Great Republ Dr Gloucester MA 01930 USA Lunds Fisheries Inc 997 Ocean Dr Cape May NJ 08204 USA Town Dock 45 State St Narragansett RI 02882 USA F V Retriever F V Defiance 615 Goshen Rd Cape May Court House NJ 08210 USA Hooked Seafood 615 Goshen Rd Cape May Court House NJ 08210 USA Seafreeze Ltd 100 Davisville Pier North Kingstown RI 02852 USA Seafreeze Shoreside 75 State St Narragansett RI 02882 USA

The United States Northern Shortfin squid fishery is known for its large fluctuations in catch at annual scales. In the last 5 years, this fishery has experienced increased availability of Illex illecebrosus along the Northeast US continental shelf (NES), resulting in high catch per unit effort (CPUE) and early fishery closures due to quota exceedance. The fishery occurs within the Northwest Atlantic, whose complex dynamics are set up by the interplay between the large-scale Gulf Stream, mesoscale eddies, Shelfbreak Jet, and shelf-slope exchange processes. Our ability to understand and quantify this regional variability is requisite for understanding the availability patterns of Illex, which are largely influenced by oceanographic conditions. In an effort to advance our current understanding of the seasonal and interannual variability in this species' relative abundance on the NES, we used generalized additive models to examine the relationships between the physical environment and hotspots of productivity to changes in CPUE of I. illecebrosus in the Southern stock component, which comprises the US fishery. Specifically, we derived oceanographic indicators by pairing high-resolution remote sensing data and global ocean reanalysis physical data to high-resolution fishery catch data. We identified a suite of environmental covariates that were strongly related to instances of higher catch rates. In particular, bottom temperature, warm core rings, subsurface features, and frontal dynamics together serve as indicators of habitat condition and primary productivity hotspots, providing great utility for understanding the distribution of Illex with the potential for forecasting seasonal and interannual availability.

关键词： environmental covariates generalized additive model Illex illecebrosus northern shortfin squid Northwest Atlantic remote sensing warm core rings

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Short-term forecasting of COVID-19 using support vector regression: An application using Zimbabwean data

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AMERICAN JOURNAL OF INFECTION CONTROL 2023年第10期51卷 1095-1107页

作者： Shoko, Claris Sigauke, Caston Univ Botswana Fac Social Sci Dept Stat Gaborone Botswana Univ Venda Dept Math & Computat Sci Limpopo South Africa Univ Botswana Dept Stat Private Bag UB Gaborone 00705 Botswana

Background: This study aims to show that including pairwise hierarchical interactions of covariates and combining forecasts from individual models improves prediction accuracy. Methods: The least absolute shrinkage and selection operator via hierarchical pairwise interaction is used in selecting variables that are not correlated and with the greatest predictive power in single forecast models (Gradient boosting method [GBM], generalized additive models [GAMs], Support vector regression [SVR]) are used in the analysis. The best model was selected based on the mean absolute error (MAE), the best key performance indicator for skewed data. Forecasts from the 5 models were combined using linear quantile regression averaging (LQRA). Box and Whiskers plots are used to diagnose the overall performance of fitted models. Results: Single forecast models (GBM, GAMs, and SVRs) show that including pairwise interactions improves forecast accuracy. The SVR model with interactions based on the radial basis kernel function is the best from single forecast models with the lowest MAE. Combining point forecasts from all the single forecast models using the LQRA approach further reduces the MAE. However, based on the Box and Whiskers plot, the SVR model with pairwise interactions has the smallest range. Conclusions: Based on the key performance indicators, combining predictions from several individual models improves forecast accuracy. However, overall, the SVM with pairwise hierarchical interactions outperforms all the other models (c) 2023 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

关键词： Hierarchical interactions Least absolute shrinkage Linear quantile regression averaging LASSO generalized additive model Support vector regression

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Long-term declining in carbon monoxide(CO)at a rural site of Beijing during 2006-2018 implies the improved combustion efficiency and effective emission control

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Journal of Environmental Sciences 2022年第5期34卷 432-442页

作者： Yingruo Li Zhiqiang Ma Tingting Han Weijun Quan Junxia Wang Huaigang Zhou Di He Fan Dong Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China Key Laboratory of Atmospheric Chemistry China Meteorological AdministrationBeijing 100081China Environmental Meteorology Forecast Center of Beijing-Tianjin-Hebei China Meteorological AdministrationBeijing 100089China College of Environmental Science and Engineering Peking UniversityBeijing 100871China

Carbon monoxide(CO)is primarily the result of incomplete combustion,which has impor-tant impacts on the atmospheric chemical cycle and *** quantitative char-acterization of long-term CO trends is important for both atmospheric modeling and the design and implementation of policies to efficiently control multiple *** to the limitations of high time-resolution and high-quality long-term observational data,studies on long-term trends in the CO concentration in China are quite *** this study,the observational data of the concentration of CO in a rural site of Beijing during 2006-2018 was used to analyze the long-term trend in CO concentration in *** Theil-Sen method and the generalized additive model(GAM)-based method,were used to conduct the trend estimation *** found that the concentration of CO at the Shangdianzi site showed a significant downward trend during 2006-2018,with a decline rate of 22.8±5.1 ppbV per *** declining trend in CO also showed phasic characteristics,with a fast decreasing rate during the period of 2006-2008,stable variations during the period of 2009-2013 and a continuous downward trend after *** declining trend in the CO concentration in the south to west(S-W)sectors where the polluted air masses come from is more rapid than that in the sectors where the clean air masses come *** declining trend in the CO concentration implies the improved combustion efficiency and the successful air pollution control policies in Beijing and the surrounding area.

关键词： Carbon monoxide Long-term trend Theil-Sen method generalized additive model (GAM)-based method Stratified analysis

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Association between dietary vitamin E intake and cognitive decline among old American: National Health and Nutrition Examination Survey

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EUROPEAN GERIATRIC MEDICINE 2023年第5期14卷 1027-1036页

作者： Zhang, Kai Han, Yu Gu, Zhaoxuan Hou, Zhengyan Yu, Xiaoqi Gao, Min Cai, Tianyi Gao, Yafang Xie, Jinyu Gu, Fangming Chen, Jianguo Chen, Bowen Liu, Tianzhou Jilin Univ Second Hosp 218 Ziqiang St Changchun Jilin Peoples R China First Hosp Jilin Univ Dept Ophthalmol 71 Xinmin St Changchun Jilin Peoples R China Jilin Univ Bethune Second Sch Clin Med 828 Xinmin St Changchun Jilin Peoples R China Jilin Univ Bethune First Coll Clin Med 828 Xinmin St Changchun Jilin Peoples R China Jilin Univ Second Hosp Dept Gastrointestinal Nutr & Hernia Surg 218 Ziqiang St Changchun Jilin Peoples R China

AimThis study aimed to investigate changes in vitamin E intake in older adults with low cognitive performance using *** increased dietary intake of vitamin E has been associated with decreased cognitive impairment in individuals over 60 years old. The dose-response curve showed an L-shaped association between dietary vitamin E intake and cognitive decline in US adults, with an inflection point of approximately 9.296 mg/*** findings highlight the importance of including vitamin E-rich foods in the diet, particularly for older adults who may be at a higher risk of cognitive impairment. However, further research is needed to confirm these results and to better understand the mechanisms underlying the relationship between vitamin E and cognitive function. PurposeNumerous studies have reported that vitamin E plays a key role in nervous system development and neurotransmitter production. This study aimed to investigate changes in vitamin E intake in older adults with low cognitive performance using *** this cross-sectional study, we examined a sample of 2255 American adults aged 60 and over between 2011 and 2014. We collected dietary data by averaging two recalls for dietary use to determine vitamin E intake. We assessed cognitive function using five tests and analyzed the association between these variables using a multivariate logistic regression *** total of 2255 participants aged >= 60 years from the National Health and Nutrition Examination Survey (NHANES) for the 2011-2014 cycle were included in the analysis. Vitamin E intake was negatively associated with cognitive function. In the Z test, with each 1 mg/day increase in dietary intake of vitamin E, there was a 6% decrease in the correlation with cognitive impairment (OR = 0.94, 95% CI 0.91-0.97) in the fully fitted model (OR = 0.94, 95% CI 0.91-0.97). These findings remained consistent when analyzing the exposure as a categorical variable. In comparison to Q1, Q4 s

关键词： Vitamin E intake Cognition Association generalized additive model Subgroup analysis

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additive Bayesian Variable Selection under Censoring and Misspecification

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ENERGY AND BUILDINGS 2023年第1期282卷 13-29页

作者： Rossell, David Rubio, Francisco Javier Pompeu Fabra Univ Dept Econ & Business Barcelona Spain UCL Dept Stat Sci London England

We discuss the role of misspecification and censoring on Bayesian model selection in the contexts of right-censored survival and con-cave log-likelihood regression. Misspecification includes wrongly assuming the censoring mechanism to be noninformative. Emphasis is placed on ad-ditive accelerated failure time, Cox proportional hazards and probit models. We offer a theoretical treatment that includes local and nonlocal priors, and a general nonlinear effect decomposition to improve power-sparsity trade-offs. We discuss a fundamental question: what solution can one hope to obtain when (inevitably) models are misspecified, and how to interpret it? Asymptotically, covariates that do not have predictive power for neither the outcome nor (for survival data) censoring times, in the sense of reducing a likelihood-associated loss, are discarded. Misspecification and censoring have an asymptotically negligible effect on false positives, but their impact on power is exponential. We show that it can be advantageous to consider simple models that are computationally practical yet attain good power to de-tect potentially complex effects, including the use of finite-dimensional basis to detect truly nonparametric effects. We also discuss algorithms to capitalize on sufficient statistics and fast likelihood approximations for Gaussian-based survival and binary models.

关键词： additive regression generalized additive model misspecification model selection survival

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Comparison of Three Prediction models for Predicting Chronic Obstructive Pulmonary Disease in China

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INTERNATIONAL JOURNAL OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE 2023年 18卷 2961-2969页

作者： Teng, Yuhan Jian, Yining Chen, Xinyue Li, Yang Han, Bing Wang, Lei Southwest Med Univ Dept Clin Med Luzhou Sichuan Peoples R China China Med Univ Dept Publ Hlth Shenyang Liaoning Peoples R China China Med Univ Hosp 1 Dept Gen Practice 122 N Nanjing St Shenyang 110001 Liaoning Peoples R China Hunnan Zhujia Community Hlth Serv Ctr Dept Gen Practice Shenyang Liaoning Peoples R China

Purpose: To predict the future number of patients with chronic obstructive pulmonary disease (COPD) in China and compare the three prediction ***: A generalized additive model (GAM), autoregressive integrated moving average (ARIMA) model, and curve-fitting method were used to fit and predict the number of patients with COPD in China. Data on the number of patients with COPD in China from 1990 to 2019 were obtained from the Global Burden of Disease (GBD) database. The coefficient of determination (R2), mean absolute error (MAE), mean absolute percentage error (MAPE), root mean squared error (RMSE), relative error of prediction, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC) were used to evaluate and compare the fitting effect, prediction effect, and reliability of the three ***: The GAM, ARIMA, and curve-fitting methods could predict future trends in COPD in China. The performance of the GAM is the best among the three models, whereas the curve fitting method is the worst, and the ARIMA (0,1,2) model is in between. The prediction results of the three models showed that the number of patients with COPD in China is expected to increase from 2020 to ***: GAM and AIRMA models are recommended for predicting the future prevalence of COPD in China. The number of patients with COPD in China is expected to increase in the next few years. The prevention and control of COPD in China still needs to be strengthened. Using appropriate models to predict future trends in COPD will provide support for health policymakers.

关键词： generalized additive model ARIMA model curve fitting method COPD prediction

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