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  • 1
    In: Frontiers in Medicine, Frontiers Media SA, Vol. 9 ( 2022-12-16)
    Abstract: In recent years, different tools have been developed to facilitate analysis of social determinants of health (SDH) and apply this to health policy. The possibility of generating predictive models of health outcomes which combine a wide range of socioeconomic indicators with health problems is an approach that is receiving increasing attention. Our objectives are twofold: (1) to predict population health outcomes measured as hospital morbidity, taking primary care (PC) morbidity adjusted for SDH as predictors; and (2) to analyze the geographic variability of the impact of SDH-adjusted PC morbidity on hospital morbidity, by combining data sourced from electronic health records and selected operations of the National Statistics Institute ( Instituto Nacional de Estadística/INE ). Methods The following will be conducted: a qualitative study to select socio-health indicators using RAND methodology in accordance with SDH frameworks, based on indicators published by the INE in selected operations; and a quantitative study combining two large databases drawn from different Spain’s Autonomous Regions (ARs) to enable hospital morbidity to be ascertained, i.e., PC electronic health records and the minimum basic data set (MBDS) for hospital discharges. These will be linked to socioeconomic indicators, previously selected by geographic unit. The outcome variable will be hospital morbidity, and the independent variables will be age, sex, PC morbidity, geographic unit, and socioeconomic indicators. Analysis To achieve the first objective, predictive models will be used, with a test-and-training technique, fitting multiple logistic regression models. In the analysis of geographic variability, penalized mixed models will be used, with geographic units considered as random effects and independent predictors as fixed effects. Discussion This study seeks to show the relationship between SDH and population health, and the geographic differences determined by such determinants. The main limitations are posed by the collection of data for healthcare as opposed to research purposes, and the time lag between collection and publication of data, sampling errors and missing data in registries and surveys. The main strength lies in the project’s multidisciplinary nature (family medicine, pediatrics, public health, nursing, psychology, engineering, geography).
    Type of Medium: Online Resource
    ISSN: 2296-858X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2775999-4
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  • 2
    In: Statistical Modelling, SAGE Publications
    Abstract: The estimation of curve derivatives is of interest in many disciplines. It allows the extraction of important characteristics to gain insight about the underlying process. In the context of longitudinal data, the derivative allows the description of biological features of the individuals or finding change regions of interest. Although there are several approaches to estimate subject-specific curves and their derivatives, there are still open problems due to the complicated nature of these time course processes. In this article, we illustrate the use of P-spline models to estimate derivatives in the context of longitudinal data. We also propose a new penalty acting at the population and the subject-specific levels to address under-smoothing and boundary problems in derivative estimation. The practical performance of the proposal is evaluated through simulations, and comparisons with an alternative method are reported. Finally, an application to longitudinal height measurements of 125 football players in a youth professional academy is presented, where the goal is to analyse their growth and maturity patterns over time.
    Type of Medium: Online Resource
    ISSN: 1471-082X , 1477-0342
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2053876-5
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  • 3
    In: Biometrics, Wiley, Vol. 79, No. 3 ( 2023-09), p. 1972-1985
    Abstract: The receptive field (RF) of a visual neuron is the region of the space that elicits neuronal responses. It can be mapped using different techniques that allow inferring its spatial and temporal properties. Raw RF maps (RFmaps) are usually noisy, making it difficult to obtain and study important features of the RF. A possible solution is to smooth them using P‐splines. Yet, raw RFmaps are characterized by sharp transitions in both space and time. Their analysis thus asks for spatiotemporal adaptive P‐spline models, where smoothness can be locally adapted to the data. However, the literature lacks proposals for adaptive P‐splines in more than two dimensions. Furthermore, the extra flexibility afforded by adaptive P‐spline models is obtained at the cost of a high computational burden, especially in a multidimensional setting. To fill these gaps, this work presents a novel anisotropic locally adaptive P‐spline model in two (e.g., space) and three (space and time) dimensions. Estimation is based on the recently proposed SOP (Separation of Overlapping Precision matrices) method, which provides the speed we look for. Besides the spatiotemporal analysis of the neuronal activity data that motivated this work, the practical performance of the proposal is evaluated through simulations, and comparisons with alternative methods are reported.
    Type of Medium: Online Resource
    ISSN: 0006-341X , 1541-0420
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2054197-1
    SSG: 12
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  • 4
    Online Resource
    Online Resource
    Annual Reviews ; 2021
    In:  Annual Review of Statistics and Its Application Vol. 8, No. 1 ( 2021-03-07), p. 41-67
    In: Annual Review of Statistics and Its Application, Annual Reviews, Vol. 8, No. 1 ( 2021-03-07), p. 41-67
    Abstract: In this review, we present an overview of the main aspects related to the statistical evaluation of medical tests for diagnosis and prognosis. Measures of diagnostic performance for binary tests, such as sensitivity, specificity, and predictive values, are introduced, and extensions to the case of continuous-outcome tests are detailed. Special focus is placed on the receiver operating characteristic (ROC) curve and its estimation, with emphasis on the topic of covariate adjustment. The extension to the case of time-dependent ROC curves for evaluating prognostic accuracy is also touched upon. We apply several of the approaches described to a data set derived from a study aimed to evaluate the ability of homeostasis model assessment of insulin resistance (HOMA-IR) levels to identify individuals at high cardio-metabolic risk and how such discriminatory ability might be influenced by age and gender. We also outline software available for the implementation of the methods.
    Type of Medium: Online Resource
    ISSN: 2326-8298 , 2326-831X
    URL: Issue
    Language: English
    Publisher: Annual Reviews
    Publication Date: 2021
    detail.hit.zdb_id: 2750272-7
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  • 5
    Online Resource
    Online Resource
    The R Foundation ; 2021
    In:  The R Journal Vol. 13, No. 1 ( 2021), p. 525-
    In: The R Journal, The R Foundation, Vol. 13, No. 1 ( 2021), p. 525-
    Type of Medium: Online Resource
    ISSN: 2073-4859
    Language: English
    Publisher: The R Foundation
    Publication Date: 2021
    detail.hit.zdb_id: 2642918-4
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  • 6
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 2020
    In:  Journal of the Royal Statistical Society Series C: Applied Statistics Vol. 69, No. 2 ( 2020-04-01), p. 459-481
    In: Journal of the Royal Statistical Society Series C: Applied Statistics, Oxford University Press (OUP), Vol. 69, No. 2 ( 2020-04-01), p. 459-481
    Abstract: Growth curve studies are typically conducted to evaluate differences between group or treatment-specific curves. Most analyses focus solely on the growth curves, but it has been argued that the derivative of growth curves can highlight differences between groups that may be masked when considering the raw curves only. Motivated by the desire to estimate derivative curves hierarchically, we introduce a new sequence of quotient differences (empirical derivatives) which, among other things, are well behaved near the boundaries compared with other sequences in the literature. Using the sequence of quotient differences, we develop a Bayesian method to estimate curve derivatives in a multilevel setting (a common scenario in growth studies) and show how the method can be used to estimate individual and group derivative curves and to make comparisons. We apply the new methodology to data collected from a study conducted to explore the effect that radiation-based therapies have on growth in female children diagnosed with acute lymphoblastic leukaemia.
    Type of Medium: Online Resource
    ISSN: 0035-9254 , 1467-9876
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2020
    detail.hit.zdb_id: 204797-4
    detail.hit.zdb_id: 1482300-7
    detail.hit.zdb_id: 1476894-X
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  • 7
    In: Field Crops Research, Elsevier BV, Vol. 274 ( 2021-12), p. 108314-
    Type of Medium: Online Resource
    ISSN: 0378-4290
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 2012484-3
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  • 8
    Online Resource
    Online Resource
    Institute of Mathematical Statistics ; 2022
    In:  Statistical Science Vol. 37, No. 4 ( 2022-11-1)
    In: Statistical Science, Institute of Mathematical Statistics, Vol. 37, No. 4 ( 2022-11-1)
    Type of Medium: Online Resource
    ISSN: 0883-4237
    Language: Unknown
    Publisher: Institute of Mathematical Statistics
    Publication Date: 2022
    detail.hit.zdb_id: 2009740-2
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  • 9
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2023
    In:  BMC Medical Informatics and Decision Making Vol. 23, No. 1 ( 2023-08-05)
    In: BMC Medical Informatics and Decision Making, Springer Science and Business Media LLC, Vol. 23, No. 1 ( 2023-08-05)
    Abstract: The progressive ageing in developed countries entails an increase in multimorbidity. Population-wide predictive models for adverse health outcomes are crucial to address these growing healthcare needs. The main objective of this study is to develop and validate a population-based prognostic model to predict the probability of unplanned hospitalization in the Basque Country, through comparing the performance of a logistic regression model and three families of machine learning models. Methods Using age, sex, diagnoses and drug prescriptions previously transformed by the Johns Hopkins Adjusted Clinical Groups (ACG) System, we predict the probability of unplanned hospitalization in the Basque Country (2.2 million inhabitants) using several techniques. When dealing with non-deterministic algorithms, comparing a single model per technique is not enough to choose the best approach. Thus, we conduct 40 experiments per family of models - Random Forest, Gradient Boosting Decision Trees and Multilayer Perceptrons - and compare them to Logistic Regression. Models’ performance are compared both population-wide and for the 20,000 patients with the highest predicted probabilities, as a hypothetical high-risk group to intervene on. Results The best-performing technique is Multilayer Perceptron, followed by Gradient Boosting Decision Trees, Logistic Regression and Random Forest. Multilayer Perceptrons also have the lowest variability, around an order of magnitude less than Random Forests. Median area under the ROC curve, average precision and positive predictive value range from 0.789 to 0.802, 0.237 to 0.257 and 0.485 to 0.511, respectively. For Brier Score the median values are 0.048 for all techniques. There is some overlap between the algorithms. For instance, Gradient Boosting Decision Trees perform better than Logistic Regression more than 75% of the time, but not always. Conclusions All models have good global performance. The only family that is consistently superior to Logistic Regression is Multilayer Perceptron, showing a very reliable performance with the lowest variability.
    Type of Medium: Online Resource
    ISSN: 1472-6947
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2046490-3
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  • 10
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2022-02-24)
    Abstract: High throughput phenotyping (HTP) platforms and devices are increasingly used for the characterization of growth and developmental processes for large sets of plant genotypes. Such HTP data require challenging statistical analyses in which longitudinal genetic signals need to be estimated against a background of spatio-temporal noise processes. We propose a two-stage approach for the analysis of such longitudinal HTP data. In a first stage, we correct for design features and spatial trends per time point. In a second stage, we focus on the longitudinal modelling of the spatially corrected data, thereby taking advantage of shared longitudinal features between genotypes and plants within genotypes. We propose a flexible hierarchical three-level P-spline growth curve model, with plants/plots nested in genotypes, and genotypes nested in populations. For selection of genotypes in a plant breeding context, we show how to extract new phenotypes, like growth rates, from the estimated genotypic growth curves and their first-order derivatives. We illustrate our approach on HTP data from the PhenoArch greenhouse platform at INRAE Montpellier and the outdoor Field Phenotyping platform at ETH Zürich.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2615211-3
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