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  1. Article ; Online: Functional proportional hazards mixture cure model with applications in cancer mortality in NHANES and post ICU recovery.

    Ghosal, Rahul / Matabuena, Marcos / Zhang, Jiajia

    Statistical methods in medical research

    2023  Volume 32, Issue 11, Page(s) 2254–2269

    Abstract: We develop a functional proportional hazards mixture cure model with scalar and functional covariates measured at the baseline. The mixture cure model, useful in studying populations with a cure fraction of a particular event of interest is extended to ... ...

    Abstract We develop a functional proportional hazards mixture cure model with scalar and functional covariates measured at the baseline. The mixture cure model, useful in studying populations with a cure fraction of a particular event of interest is extended to functional data. We employ the expectation-maximization algorithm and develop a semiparametric penalized spline-based approach to estimate the dynamic functional coefficients of the incidence and the latency part. The proposed method is computationally efficient and simultaneously incorporates smoothness in the estimated functional coefficients via roughness penalty. Simulation studies illustrate a satisfactory performance of the proposed method in accurately estimating the model parameters and the baseline survival function. Finally, the clinical potential of the model is demonstrated in two real data examples that incorporate rich high-dimensional biomedical signals as functional covariates measured at the baseline and constitute novel domains to apply cure survival models in contemporary medical situations. In particular, we analyze (i) minute-by-minute physical activity data from the National Health And Nutrition Examination Survey 2003-2006 to study the association between diurnal patterns of physical activity at baseline and all cancer mortality through 2019 while adjusting for other biological factors; (ii) the impact of daily functional measures of disease severity collected in the intensive care unit on post intensive care unit recovery and mortality event. Our findings provide novel epidemiological insights into the association between daily patterns of physical activity and cancer mortality. Software implementation and illustration of the proposed estimation method are provided in R.
    MeSH term(s) Humans ; Models, Statistical ; Nutrition Surveys ; Proportional Hazards Models ; Computer Simulation ; Algorithms ; Neoplasms ; Survival Analysis
    Language English
    Publishing date 2023-10-19
    Publishing country England
    Document type Journal Article
    ZDB-ID 1136948-6
    ISSN 1477-0334 ; 0962-2802
    ISSN (online) 1477-0334
    ISSN 0962-2802
    DOI 10.1177/09622802231206472
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Handgrip strength conditional tolerance regions suggest the need for personalized sarcopenia definition: an analysis of the American NHANES database.

    Matabuena, Marcos / Abdalla, Pedro Pugliesi / Machado, Dalmo Roberto Lopes / Bohn, Lucimere / Mota, Jorge

    Aging clinical and experimental research

    2023  Volume 35, Issue 6, Page(s) 1369–1373

    Abstract: Background: Handgrip strength (HGS) is a well-established clinical biomarker that assesses functional capacity in older populations. In addition, HGS is a diagnostic tool that forecasts aging health conditions, such as sarcopenia.: Aims: This paper ... ...

    Abstract Background: Handgrip strength (HGS) is a well-established clinical biomarker that assesses functional capacity in older populations. In addition, HGS is a diagnostic tool that forecasts aging health conditions, such as sarcopenia.
    Aims: This paper provides HGS statistical tolerance regions and presents the need to establish HGS reference values according to patients' characteristics.
    Methods: For this purpose, we used a conditional tolerance algorithm for HGS, and we observed the tolerances regions in different age strata and sex of non-sarcopenic individuals from the National Health and Nutrition Examination Survey (NHANES, wave 2011-2012).
    Results and discussion: Our results have critical implications for sarcopenia, since conventional and available HGS cut-offs do not consider age range.
    Conclusions: This paper offers new perspectives on the evolution of traditional definitions of sarcopenia according to the principles of precision medicine.
    MeSH term(s) Humans ; United States ; Aged ; Sarcopenia/diagnosis ; Hand Strength ; Nutrition Surveys ; Aging ; Reference Values ; Muscle Strength
    Language English
    Publishing date 2023-04-04
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2104785-6
    ISSN 1720-8319 ; 1594-0667
    ISSN (online) 1720-8319
    ISSN 1594-0667
    DOI 10.1007/s40520-023-02398-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: An Improved Version of the Classical Banister Model to Predict Changes in Physical Condition.

    Matabuena, Marcos / Rodríguez-López, Rosana

    Bulletin of mathematical biology

    2019  Volume 81, Issue 6, Page(s) 1867–1884

    Abstract: In this paper, we formulate and provide the solutions to two new models to predict changes in physical condition by using the information of the training load of an individual. The first model is based on a functional differential equation, and the ... ...

    Abstract In this paper, we formulate and provide the solutions to two new models to predict changes in physical condition by using the information of the training load of an individual. The first model is based on a functional differential equation, and the second one on an integral differential equation. Both models are an extension to the classical Banister model and allow to overcome its main drawback: the variations in physical condition are influenced by the training loads of the previous days and not only of the same day. Finally, it is illustrated how the first model works with a real example of the training process of a cyclist.
    MeSH term(s) Athletic Performance/physiology ; Bicycling/physiology ; Humans ; Linear Models ; Mathematical Concepts ; Models, Biological ; Physical Conditioning, Human/statistics & numerical data ; Wearable Electronic Devices/statistics & numerical data
    Language English
    Publishing date 2019-03-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 184905-0
    ISSN 1522-9602 ; 0007-4985 ; 0092-8240
    ISSN (online) 1522-9602
    ISSN 0007-4985 ; 0092-8240
    DOI 10.1007/s11538-019-00588-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Gait and Neuromuscular Changes Are Evident in Some Masters Club Level Runners 24-h After Interval Training Run.

    Riazati, Sherveen / Caplan, Nick / Matabuena, Marcos / Hayes, Philip R

    Frontiers in sports and active living

    2022  Volume 4, Page(s) 830278

    Abstract: Purpose: To examine the time course of recovery for gait and neuromuscular function immediately after and 24-h post interval training. In addition, this study compared the impact of different statistical approaches on detecting changes.: Methods: ... ...

    Abstract Purpose: To examine the time course of recovery for gait and neuromuscular function immediately after and 24-h post interval training. In addition, this study compared the impact of different statistical approaches on detecting changes.
    Methods: Twenty (10F, 10M) healthy, recreational club runners performed a high-intensity interval training (HIIT) session consisting of six repetitions of 800 m. A 6-min medium intensity run was performed pre, post, and 24-h post HIIT to assess hip and knee kinematics and coordination variability. Voluntary activation and twitch force of the quadriceps, along with maximum isometric force were examined pre, post, and 24-h post significance HIIT. The time course of changes were examined using two different statistical approaches: traditional null hypothesis significance tests and "real" changes using minimum detectable change.
    Results: Immediately following the run, there were significant (
    Conclusion: High intensity interval training resulted in altered running kinematics along with central and peripheral decrements in neuromuscular function. Most runners had recovered within 24-h, although a minority still exhibited signs of fatigue. The runners that were not able to recover prior to their run at 24-h were identified to be at an increased risk of running-related injury.
    Language English
    Publishing date 2022-06-02
    Publishing country Switzerland
    Document type Journal Article
    ISSN 2624-9367
    ISSN (online) 2624-9367
    DOI 10.3389/fspor.2022.830278
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Kernel machine learning methods to handle missing responses with complex predictors. Application in modelling five-year glucose changes using distributional representations.

    Matabuena, Marcos / Félix, Paulo / García-Meixide, Carlos / Gude, Francisco

    Computer methods and programs in biomedicine

    2022  Volume 221, Page(s) 106905

    Abstract: Background and objectives: Missing data is a ubiquitous problem in longitudinal studies due to the number of patients lost to follow-up. Kernel methods have enriched the machine learning field by successfully managing non-vectorial predictors, such as ... ...

    Abstract Background and objectives: Missing data is a ubiquitous problem in longitudinal studies due to the number of patients lost to follow-up. Kernel methods have enriched the machine learning field by successfully managing non-vectorial predictors, such as graphs, strings, and probability distributions, and have emerged as a promising tool for the analysis of complex data stemming from modern healthcare. This paper proposes a new set of kernel methods to handle missing data in the response variables. These methods will be applied to predict long-term changes in glycated haemoglobin (A1c), the primary biomarker used to diagnose and monitor the progression of diabetes mellitus, making emphasis on exploring the predictive potential of continuous glucose monitoring (CGM).
    Methods: We propose a new framework of non-linear kernel methods for testing statistical independence, selecting relevant predictors, and quantifying the uncertainty of the resultant predictive models. As a novelty in the clinical analysis, we used a distributional representation of CGM as a predictor and compared its performance with that of traditional diabetes biomarkers.
    Results: The results show that, after the incorporation of CGM information, predictive ability increases from R
    Conclusions: The proposed methods have proven to deal effectively with missing data. They also have the potential to improve the results of predictive tasks by including new complex objects as explanatory variables and modelling arbitrary dependence relations. The application of these methods to a longitudinal study of diabetes showed that the inclusion of a distributional representation of CGM data provides greater sensitivity in predicting five-year A1c changes than classical diabetes biomarkers and traditional CGM metrics.
    MeSH term(s) Biomarkers ; Blood Glucose/metabolism ; Blood Glucose Self-Monitoring/methods ; Diabetes Mellitus ; Diabetes Mellitus, Type 1 ; Glucose ; Glycated Hemoglobin A/metabolism ; Humans ; Longitudinal Studies ; Machine Learning
    Chemical Substances Biomarkers ; Blood Glucose ; Glycated Hemoglobin A ; Glucose (IY9XDZ35W2)
    Language English
    Publishing date 2022-05-25
    Publishing country Ireland
    Document type Journal Article
    ZDB-ID 632564-6
    ISSN 1872-7565 ; 0169-2607
    ISSN (online) 1872-7565
    ISSN 0169-2607
    DOI 10.1016/j.cmpb.2022.106905
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Reproducibility of continuous glucose monitoring results under real-life conditions in an adult population: a functional data analysis.

    Matabuena, Marcos / Pazos-Couselo, Marcos / Alonso-Sampedro, Manuela / Fernández-Merino, Carmen / González-Quintela, Arturo / Gude, Francisco

    Scientific reports

    2023  Volume 13, Issue 1, Page(s) 13987

    Abstract: Continuous glucose monitoring systems (CGM) are a very useful tool to understand the behaviour of glucose in different situations and populations. Despite the widespread use of CGM systems in both clinical practice and research, our understanding of the ... ...

    Abstract Continuous glucose monitoring systems (CGM) are a very useful tool to understand the behaviour of glucose in different situations and populations. Despite the widespread use of CGM systems in both clinical practice and research, our understanding of the reproducibility of CGM data remains limited. The present work examines the reproducibility of the results provided by a CGM system in a random sample of a free-living adult population, from a functional data analysis approach. Functional intraclass correlation coefficients (ICCs) and their 95% confidence intervals (CI) were calculated to assess the reproducibility of CGM results in 581 individuals. 62% were females 581 participants (62% women) mean age 48 years (range 18-87) were included, 12% had previously been diagnosed with diabetes. The inter-day reproducibility of the CGM results was greater for subjects with diabetes (ICC 0.46 [CI 0.39-0.55]) than for normoglycaemic subjects (ICC 0.30 [CI 0.27-0.33]); the value for prediabetic subjects was intermediate (ICC 0.37 [CI 0.31-0.42]). For normoglycaemic subjects, inter-day reproducibility was poorer among the younger (ICC 0.26 [CI 0.21-0.30]) than the older subjects (ICC 0.39 [CI 0.32-0.45]). Inter-day reproducibility was poorest among normoglycaemic subjects, especially younger normoglycaemic subjects, suggesting the need to monitor some patient groups more often than others.
    MeSH term(s) Humans ; Adult ; Female ; Adolescent ; Young Adult ; Middle Aged ; Aged ; Aged, 80 and over ; Male ; Blood Glucose ; Blood Glucose Self-Monitoring ; Reproducibility of Results ; Data Analysis ; Glucose
    Chemical Substances Blood Glucose ; Glucose (IY9XDZ35W2)
    Language English
    Publishing date 2023-08-26
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-023-40949-1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Uncertainty Quantification in Medicine Science: The Next Big Step.

    Hammouri, Ziad Akram Ali / Mier, Pablo Rodríguez / Félix, Paulo / Mansournia, Mohammad Ali / Huelin, Fernando / Casals, Martí / Matabuena, Marcos

    Archivos de bronconeumologia

    2023  Volume 59, Issue 11, Page(s) 760–761

    MeSH term(s) Humans ; Uncertainty ; Precision Medicine
    Language Spanish
    Publishing date 2023-07-22
    Publishing country Spain
    Document type Case Reports
    ZDB-ID 733126-5
    ISSN 1579-2129 ; 0300-2896
    ISSN (online) 1579-2129
    ISSN 0300-2896
    DOI 10.1016/j.arbres.2023.07.018
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Author Correction: Reassessment of fluctuating dental asymmetry in Down syndrome.

    Matabuena Rodríguez, Marcos / Diz Dios, Pedro / Cadarso-Suárez, Carmen / Diniz-Freitas, Márcio / Outumuro Rial, Mercedes / Abeleira Pazos, Maria Teresa / Limeres Posse, Jacobo

    Scientific reports

    2024  Volume 14, Issue 1, Page(s) 1377

    Language English
    Publishing date 2024-01-16
    Publishing country England
    Document type Published Erratum
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-024-51672-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Book ; Online: Neural interval-censored Cox regression with feature selection

    Meixide, Carlos García / Matabuena, Marcos / Kosorok, Michael R.

    2022  

    Abstract: The classical Cox model emerged in 1972 promoting breakthroughs in how patient prognosis is quantified using time-to-event analysis in biomedicine. One of the most useful characteristics of the model for practitioners is the interpretability of the ... ...

    Abstract The classical Cox model emerged in 1972 promoting breakthroughs in how patient prognosis is quantified using time-to-event analysis in biomedicine. One of the most useful characteristics of the model for practitioners is the interpretability of the variables in the analysis. However, this comes at the price of introducing strong assumptions concerning the functional form of the regression model. To break this gap, this paper aims to exploit the explainability advantages of the classical Cox model in the setting of interval-censoring using a new Lasso neural network that simultaneously selects the most relevant variables while quantifying non-linear relations between predictors and survival times. The gain of the new method is illustrated empirically in an extensive simulation study with examples that involve linear and non-linear ground dependencies. We also demonstrate the performance of our strategy in the analysis of physiological, clinical and accelerometer data from the NHANES 2003-2006 waves to predict the effect of physical activity on the survival of patients. Our method outperforms the prior results in the literature that use the traditional Cox model.
    Keywords Statistics - Machine Learning ; Computer Science - Machine Learning ; Statistics - Methodology
    Subject code 310
    Publishing date 2022-06-14
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Glucodensities: A new representation of glucose profiles using distributional data analysis.

    Matabuena, Marcos / Petersen, Alexander / Vidal, Juan C / Gude, Francisco

    Statistical methods in medical research

    2021  Volume 30, Issue 6, Page(s) 1445–1464

    Abstract: ... through an application in diabetes with continuous-time glucose monitoring (CGM) data. In this domain, we show marked ...

    Abstract Biosensor data have the potential to improve disease control and detection. However, the analysis of these data under free-living conditions is not feasible with current statistical techniques. To address this challenge, we introduce a new functional representation of biosensor data, termed the glucodensity, together with a data analysis framework based on distances between them. The new data analysis procedure is illustrated through an application in diabetes with continuous-time glucose monitoring (CGM) data. In this domain, we show marked improvement with respect to state-of-the-art analysis methods. In particular, our findings demonstrate that (i) the glucodensity possesses an extraordinary clinical sensitivity to capture the typical biomarkers used in the standard clinical practice in diabetes; (ii) previous biomarkers cannot accurately predict glucodensity, so that the latter is a richer source of information and; (iii) the glucodensity is a natural generalization of the time in range metric, this being the gold standard in the handling of CGM data. Furthermore, the new method overcomes many of the drawbacks of time in range metrics and provides more in-depth insight into assessing glucose metabolism.
    MeSH term(s) Blood Glucose ; Blood Glucose Self-Monitoring ; Data Analysis ; Diabetes Mellitus ; Diabetes Mellitus, Type 1 ; Glucose ; Humans
    Chemical Substances Blood Glucose ; Glucose (IY9XDZ35W2)
    Language English
    Publishing date 2021-03-24
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1136948-6
    ISSN 1477-0334 ; 0962-2802
    ISSN (online) 1477-0334
    ISSN 0962-2802
    DOI 10.1177/0962280221998064
    Database MEDical Literature Analysis and Retrieval System OnLINE

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