Sonia Pérez‐Fernández

Universidad de Oviedo

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Pablo Martínez‐Camblor

Dartmouth College

Susana Díaz‐Coto

Dartmouth Health

Norberto Corral

Universidad de Oviedo

Peter Filzmoser

TU Wien

José Antonio Ros

Hospital Universitario Virgen de la Arrixaca

Diana Ceballos‐Francisco

Universidad de Murcia

Manuel Muro

Instituto Murciano de Investigación Biosanitaria

Wilder T. Doucette

Dartmouth College

Alfredo Minguela

Instituto Murciano de Investigación Biosanitaria

Cristina Ortuño-Hernández

Instituto Murciano de Investigación Biosanitaria

Cooperative Institutions

Universidad de Oviedo

Instituto de Investigación Sanitaria del Principado de Asturias

Central University Hospital of Asturias

Instituto Murciano de Investigación Biosanitaria

Gobierno del Principado de Asturias

Hospital Universitario Virgen de la Arrixaca

Instituto de Salud Carlos III

Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas

Dartmouth College

Universidad de Murcia

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Efficient nonparametric confidence bands for receiver operating-characteristic curves

Statistical Methods in Medical Research (2016)

Pablo Martínez‐Camblor Sonia Pérez‐Fernández Norberto Corral

Receiver operating-characteristic curve is a popular graphical method frequently used in order to study the diagnostic capacity of continuous (bio)markers. In spite of the existence of a huge number of papers devoted to both theoretical and practical aspects of this topic, the construction of confidence bands has had little impact in the specialized literature. As far as the authors know, in the CRAN there are only three R packages providing receiver operating-characteristic curve confidence regions: plotROC, pROC and fbroc. This work tries to fill this gap studying and proposing a new nonparametric method to build confidence bands for both the standard receiver operating-characteristic curve and its generalization for nonmonotone relationships. The behavior of the proposed procedure is studied via Monte Carlo simulations and the methodology is applied on two real-world biomedical problems. In addition, an R function to compute the proposed and some of the previously existing methodologies is provided as online supplementary material.

10.1177/0962280216672490

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Citations (7)

smoothROCtime: an R package for time-dependent ROC curve estimation

Computational Statistics (2020)

Susana Díaz‐Coto Pablo Martínez‐Camblor Sonia Pérez‐Fernández

R package

10.1007/s00180-020-00955-7

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Citations (12)

Impact of general practitioner appointment frequency on disease management in type 2 diabetes mellitus patients

Primary care diabetes (2025)

Miguel García-Villarino Pablo Martínez‐Camblor Ana Victoria García Elsa Villa-Fernández Sonia Pérez‐Fernández

Disease management

10.1016/j.pcd.2025.01.007

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Effect of Type of Dialysis on CMV-Specific CD8+ T Cells in Kidney Transplant Candidates

Frontiers in Immunology (2019)

José Ramón Vidal-Castiñeira Viviana Corte-Iglesias L Sobrino-Díaz Sonia Pérez‐Fernández Santiago Melón

BACKGROUND: Dialysis is the first procedure to partially replace renal function in end-stage renal diseases, despite several adverse side effects, such as infections. The primary aim of this study was to evaluate the levels of immune CMV-specific CD8+ T cells in a representative cohort of pre-transplant patients receiving hemodialysis (HD) or peritoneal dialysis (PD). The secondary aim was to monitor the CMV-specific CD8+ T cells in kidney transplant recipients undergoing different types of dialysis during the first year following their transplant. METHODS: 69 patients were enrolled and examined with respect to the type of dialysis they received. HLA class I dextramers for CMV were used to determine the quantity of CMV-specific CD8+ T cells. The CMV DNA viral load was also determined. Forty-two of the patients enrolled in the study underwent solid organ transplantation and were analyzed during their first year post-transplantation. RESULTS: Patients receiving HD had fewer CMV-specific CD8+ T cells than those in PD (p<0.05). We also observed that patients in PD had more CMV-specific CD8+ T cells during the follow-up period than those in HD (p<0.05), independently of the CMV DNA. Finally, PD patients had a higher frequency of CD8+ Effector-Memory RA T cells (TEMRA) and a lower frequency of central memory T cells (TCM) than did HD patients. CONCLUSIONS: These results indicate the better status of CMV-specific T cell immunity in PD patients. The use of CMV T cell dextramers would be advantageous for monitoring the CD8+ T-specific response, enabling the use of prophylactic treatment to be optimized.

10.3389/fimmu.2019.01680

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Citations (1)

An analysis of the median of a fuzzy random variable based on Zadeh’s extension principle

Advances in intelligent systems research/Advances in Intelligent Systems Research (2015)

Sonia Pérez‐Fernández Beatriz Sinova

The median of a fuzzy random variable has been extended either by applying Zadeh's extension principle or by minimizing its mean distance w.r.t. a fuzzy number when a certain L 1 metric is considered.This paper aims to analyze connections between both approaches along with some properties of the first one, as well as some simulation studies to show that it also behaves better than the Aumanntype mean.

10.2991/ifsa-eusflat-15.2015.125

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Cumulative/dynamic ROC curve estimation

Journal of Statistical Computation and Simulation (2016)

Pablo Martínez‐Camblor Gustavo F. Bayón Sonia Pérez‐Fernández

Receiver operating-characteristic (ROC) curve is a popular graphical method frequently used in order to study the diagnostic capacity of continuous (bio)markers. When the considered outcome is a time-dependent variable, the direct generalization is known as cumulative/dynamic ROC curve. For a fixed point of time, t, one subject is allocated into the positive group if the event happens before t and into the negative group if the event is not happened at t. The presence of censored subject, which can not be directly assigned into a group, is the main handicap of this approach. The proposed cumulative/dynamic ROC curve estimator assigns a probability to belong to the negative (positive) group to the subjects censored previously to t. The performance of the resulting estimator is studied from Monte Carlo simulations. Some real-world applications are reported. Results suggest that the new estimators provide a good approximation to the real cumulative/dynamic ROC curve.

10.1080/00949655.2016.1175442

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Citations (19)

movieROC: Visualizing the Decision Rules Underlying Binary Classification

Sonia Pérez‐Fernández

Visualization of decision rules for binary classification and Receiver Operating Characteristic (ROC) curve estimation under different generalizations: - making the classification subsets flexible to cover those scenarios where both extremes of the marker are associated with a higher risk of being positive, considering two thresholds (gROC curve); - transforming the marker by a function either defined by the user or resulting from a logistic regression model (hROC curve); - considering a linear transformation with some fixed parameters introduced by the user, dynamic parameters or empirically maximizing TPR for each FPR for a bivariate marker. Also a quadratic transformation with particular coefficients or a function fitted by a logistic regression model can be considered (biROC curve); - considering a linear transformation with some fixed parameters introduced by the user, dynamic parameters or a function fitted by a logistic regression model (multiROC curve). The classification regions behind each point of the ROC curve are displayed in both fixed graphics (plot.buildROC(), plot.regions() or plot.funregions() function) or videos (movieROC() function).

Binary decision diagram

10.32614/cran.package.movieroc

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The role of the p-value in the multitesting problem

Journal of Applied Statistics (2019)

Pablo Martínez‐Camblor Sonia Pérez‐Fernández Susana Díaz‐Coto

Modern science frequently involves the analysis of large amount of quantitative information and the simultaneous testing of thousands or even hundreds of thousands null hypotheses. In this context, sometimes, naive deductions derived from the statistical reports substitute the rational thinking. The reproducibility crisis is a direct consequence of the misleading statistical conclusions. In this paper, the authors revisit some of the controversies on the implications derived from the statistical hypothesis testing. They focus on the role of the p-value on the massive multitesting problem and the loss of its standard probabilistic interpretation. The analogy between the hypothesis tests and the usual diagnostic process (both involve a decision-making) is used to point out some limitations in the probabilistic p-value interpretation and to introduce the receiver-operating characteristic, ROC, curve as a useful tool in the large-scale multitesting context. The analysis of the well-known Hedenfalk data illustrates the problem.

Value (mathematics)

p-value

10.1080/02664763.2019.1682128

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Citations (5)

A Diagnostic Test Approach for Multitesting Problems

Studies in systems, decision and control (2018)

Pablo Martínez‐Camblor Sonia Pérez‐Fernández Norberto Corral

10.1007/978-3-319-73848-2_26

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Analyzing the Influence of the Rating Scale for Items in a Questionnaire on Cronbach Coefficient Alpha

Studies in systems, decision and control (2022)

Marı́a Asunción Lubiano Manuel Montenegro Sonia Pérez‐Fernández Marı́a Ángeles Gil

10.1007/978-3-031-04137-2_32

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Citations (5)