Inmaculada Arostegui

• Professor at University of the Basque Country

Logistic regression models are widely applied in daily practice. Hence, it is necessary to ensure they have an adequate predictive performance, which is usually estimated by means of the receiver operating characteristic (ROC) curve and the area under it (area under the curve [AUC]). Traditional estimators of these parameters are thought to be appl...

The relationship between exposure to air pollution and the severity of coronavirus disease 2019 (COVID-19) pneumonia and other outcomes is poorly understood. Beyond age and comorbidity, risk factors for adverse outcomes including death have been poorly studied. The main objective of our study was to examine the relationship between exposure to outd...

Variable selection is an important step to end up with good prediction models. LASSO regression models are one of the most commonly used methods for this purpose, for which cross‐validation is the most widely applied validation technique to choose the tuning parameter . Validation techniques in a complex survey framework are closely related to “rep...

Patient-reported outcomes (PROs) are often used as primary outcomes in clinical research studies. PROs are usually measured in ordinal scales and they tend to have excess variability beyond the binomial distribution, a property called overdispersion. Beta-binomial distribution has been previously proposed in this context in order to fit PROs, and b...

With the COVID-19 pandemic having caused unprecedented numbers of infections and deaths, large research efforts have been undertaken to increase our understanding of the disease and the factors which determine diverse clinical evolutions. Here we focused on a fully data-driven exploration regarding which factors (clinical or otherwise) were most in...

In complex survey data, each sampled observation has assigned a sampling weight, indicating the number of units that it represents in the population. Whether sampling weights should or not be considered in the estimation process of model parameters is a question that still continues to generate much discussion among researchers in different fields....

Background: A reliable anticipation of a difficult airway may notably enhance safety during anaesthesia. In current practice, clinicians use bedside screenings by manual measurements of patients' morphology. Objective: To develop and evaluate algorithms for the automated extraction of orofacial landmarks, which characterize airway morphology. M...

Chronic obstructive pulmonary disease (COPD) is understood as a complex, heterogeneous and multisystem airway obstructive disease. The association of deterioration in health-related quality of life (HRQoL) with mortality and hospitalisation for COPD exacerbation has been explored in general terms. The specific objectives of this study were to deter...

Introducción La contaminación del aire exterior se ha relacionado con mayor gravedad de las infecciones respiratorias. Por tanto, su inclusión en algoritmos predictivos podrían añadir información para pronosticar la gravedad de neumonías SARS-CoV-2. Material y métodos Estudio observacional longitudinal retrospectivo de cohortes, multicéntrico en 4...

Introducción La evidencia científica disponible señala que la contaminación del aire exterior podría agravar la severidad de la COVID-19 y por ende, incrementar las probabilidades de fallecimiento. Material y métodos Estudio observacional longitudinal retrospectivo de cohortes, multicéntrico en 4 hospitales: 2 en Bizkaia (1 urbano, 1 urbano-rural),...

LABURPENA: Lan-ingurunean bizimodu osasungarriak sustatzea funtsezkoa da langileen osasuna eta autonomia ahalik eta hoberen mantentzeko. Gero eta interes handiagoa dago gehiegizko pisuaren, obesitatearen eta ohitura osasungarrien arteko erlazioa aztertzeko, eta bai jarduera fisikoa edo loaren iraupena eta kalitatea, lanaldiarekiko elkarreraginetan...

Objective High participation determines the success of colorectal cancer screening programmes in reducing incidence and mortality. The factors that determine participation must be studied from the perspective of professionals that implement the programme. The aim was to identify factors that facilitate or hinder the participation of the invited peo...

Background: The aim of this study was to identify predictors of mortality in elderly patients undergoing colorectal cancer surgery and to develop a risk score. Methods: This was an observational prospective cohort study. Individuals over 80 years diagnosed with colorectal cancer and treated surgically were recruited in 18 hospitals in the Spanis...

Simulation models are used extensively to evaluate the performance of fisheries management strategies, though they must be validated to ensure that they accurately represent the real system. One of the quantitative methods available to advance in the process of validating simulation models is global sensitivity analysis (GSA). However, its use in f...

Fundamentos: El Gobierno Vasco (España) aprobó en 2008 un programa de detección del cáncer colorrectal de base poblacional en Atención Primaria. Se ha logrado una cobertura del 100% con una tasa de participación media del 68,4%. Los profesionales de medicina y enfermería desempeñan un papel fundamental en su implementación. El objetivo fue describi...

Objective: The Basque Government (Spain) approved a population based Colorectal Cancer Screening Programme in 2008 with its base on Primary Healthcare. Since then, a coverage of 100% of the population and an average participation rate of 68.4% have been achieved. General Practitioners and nurses play a central role on its implementation. The aim o...

The high impact of the lymph node ratio as a prognostic factor is widely established in colorectal cancer, and is being used as a categorized predictor variable in several studies. However, the cut-off points as well as the number of categories considered differ considerably in the literature. Motivated by the need to obtain the best categorization...

Background: Health-related quality of life (HRQoL) should be seen as a tool that provides an overall view of the general clinical condition of a COPD patient. The aims of this study were to identify variables associated with HRQoL and whether they continue to have an influence in the medium term, during follow-up. Methods: Overall, 543 patients...

Background: While the proportion of colon cancer occurring in older patients is expected to increase, these patients may have more complications that may lead to serious consequences. The aim of this study was assess postoperative complications and their short-term consequences in colon cancer surgery according to age. Patients and methods: Pati...

Conducting global sensitivity analysis using variance decomposition methods in complex simulation models with many input factors is usually unaffordable. An alternative is to first apply a screening method to reduce the number of input factors and then apply a variance decomposition method to the reduced model. However, usually selection of input f...

Objective The goal of this study is to identify potential factors that have a significant effect on anxiety and depression of patients with eating disorders (ED) using the beta‐binomial regression (BBR) approach on a broad sample of patients. Method This cross‐sectional study involved 520 ED patients. The effect of sociodemographics, core symptoms...

Objective Our aim was to assess the impact of comorbidities on existing COPD prognosis scores. Patients and methods A total of 543 patients with COPD (FEV1 <80% and FEV1/FVC <70%) were included between January 2003 and January 2004. Patients were stable for at least 6 weeks before inclusion and were followed for 5 years without any intervention by...

Patient‐reported outcomes (PROs) are currently being increasingly used as primary outcome measures in observational and experimental studies since they inform clinicians and researchers about the health‐status of patients and generate data to facilitate improved care. PROs usually appear as discrete and bounded with U, J, or inverse J shapes, and h...

Background Tools to aid in the prognosis assessment of colon cancer patients in terms of risk of mortality are needed. Goals of this study are to develop and validate clinical prediction rules for 1- and 2-year mortality in these patients. Methods This is a prospective cohort study of patients diagnosed with colon cancer who underwent surgery at 2...

Objective: There is limited information on health service use or patient-reported outcomes when comparing the effectiveness of laparoscopic with that of open surgery. The aim was to compare the effectiveness of laparoscopic with that of open surgery up to 2 years after intervention in patients with colon cancer. Methods: Prospective cohort study...

Background: Chronic obstructive pulmonary disease (COPD) is a common chronic disease. Exacerbations of COPD (eCOPD) contribute to the worsening of the disease and the patient's evolution. There are some clinical prediction rules that may help to stratify patients with eCOPD by their risk of poor evolution or adverse events. The translation of thes...

BACKGROUND Chronic obstructive pulmonary disease (COPD) is a common chronic disease. Exacerbations of COPD (eCOPD) contribute to the worsening of the disease and the patient’s evolution. There are some clinical prediction rules that may help to stratify patients with eCOPD by their risk of poor evolution or adverse events. The translation of these...

Objectives: To validate the EAHFE-3D scale, based on the Acute Heart Failure in Emergency Departments registry, in a cohort of patients attended for acute heart failure. Material and methods: Study of a multipurpose cohort of patients with acute heart failure in 3 hospitals in the Basque Country between 2011 and 2013. We extracted age, baseline...

Introduction Colorectal cancer is one of the most frequently diagnosed malignancies and a common cause of cancer-related mortality. The aim of this study was to develop and validate a clinical predictive model for 1-year mortality among patients with colon cancer who survive for at least 30 days after surgery. Methods Patients diagnosed with colon...

Results of internal validation of the CART analysis by bootstrap resampling (N=2000). Abbreviation: CART, classification and regression trees.

There is a need to assess human and ecosystem health effects of copper oxide nanoparticles (CuO NPs), extensively used in many industrial products. Here, we aimed to determine the cytotoxicity and cellular mechanisms involved in the toxicity of CuO NPs in mussel cells (hemocytes and gill cells) in parallel with exposures to ionic Cu and bulk CuO, a...

The Cox proportional hazards model is themost widely used survival prediction model for analysing time-to-event data. To measure the discrimination ability of a survival model the concordance probability index is widely used. In this work we studied and compared the performance of two different estimators of the concordance probability when a conti...

Recent advances in information technologies are generating a growth in the amount of available biomedical data. In this paper, we studied the impact sample size may have on the categorisation of a continuous predictor variable in a logistic regression setting. Two different approaches to categorise predictor variables were compared.

The extensive use and release to the aquatic environment of silver nanoparticles (NPs) could lead to their incorporation into the food web. Brine shrimp larvae of 24 h showed low sensitivity to the exposure to PVP/PEI-coated Ag NPs (5 nm), with EC50 values at 24 h of 19.63 mg Ag L− 1, but they significantly accumulated silver after 24 h of exposure...

Health-related quality of life has become an increasingly important indicator of health status in clinical trials and epidemiological research. Moreover, the study of the relationship of health-related quality of life with patients and disease characteristics has become one of the primary aims of many health-related quality of life studies. Health-...

Background: Although subtypes of chronic obstructive pulmonary disease are recognized, it is unknown what happens to these subtypes over time. Our objectives were to assess the stability of cluster-based subtypes in patients with stable disease and explore changes in clusters over 1 year. Methods: Multiple correspondence and cluster analysis wer...

Background: Creating an easy-to-use instrument to identify predictors of short-term (30/60-day) mortality after an exacerbation of chronic obstructive pulmonary disease (eCOPD) could help clinicians choose specific measures of medical care to decrease mortality in these patients. The objective of this study was to develop and validate a classifica...

Model validation has become a topic of great interest to many fields such as industry, medicine or even to government. Its main challenge is to provide stable and credible tools so that the decision-maker with the information necessary can make high-consequence judgments. This process requires simulation modelling and consequently, some guidelines...

Prediction models are gaining importance in many areas such as medicine, meteorology, finance, toxicology, etc. In this context, a common distribution for the response variable is the binomial distribution and hence the logistic regression model is a commonly used regression modelling approach. Although it is not recommended from a statistical poin...

When developing prediction models for application in clinical practice, health practitioners usually categorise clinical variables that are continuous in nature. Although categorisation is not regarded as advisable from a statistical point of view, due to loss of information and power, it is a common practice in medical research. Consequently, prov...

In observational studies with two measurements when the measured outcome pertains to a health related quality of life (HRQoL) variable, one motivation of the research may be to determine the potential predictors of the mean change of the outcome of interest. It is very common in such studies for data to be missing, which can bias the results. Diffe...

The aim of this work was to study short-term effects on antioxidant enzyme activities and long-term genotoxic and carcinogenic potential of CuO nanoparticles (NPs) in comparison to bulk CuO and ionic copper in mussels Mytilus galloprovincialis after 21 days exposure to 10 μg Cu L(-1). Then, mussels were kept for up to 122 days in clean water. Cu ac...

Rabbits are susceptible to infection by Mycobacterium avium subspecies paratuberculosis (MAP) in both wildlife and experimental conditions. Under the hypotheses that nutrient balance might influence the establishment of infection, we designed an experiment where MAP intestinal colonization was assessed under three dietary regimens: high fiber, high...

Silver nanoparticles (Ag NPs) are increasingly used in many products and are expected to end up in the aquatic environment. Mussels have been proposed as marine model species to evaluate NP toxicity in vitro. The objective of this work was to assess the mechanisms of toxicity of Ag NPs on mussel hemocytes and gill cells, in comparison to ionic and...

Metal-bearing nanoparticles (NPs) possess unique physico-chemical characteristics that make them useful for an increasing number of industrial products and applications, but could also confer them a higher toxicity due to their higher reactivity compared to bulk forms of the same materials. There is a considerable interest in the use of in vitro te...

There is little evidence that the guideline-recommended oxygen saturation of 92% is the best cut-off point for detecting hypoxemia in COPD exacerbations. To detect and validate pulse oximetry oxygen saturation cut-off values likely to detect hypoxemia in patients with aeCOPD, to explore the correlation between oxygen saturation measured by pulse ox...

Medikuntzan parametro kliniko asko kategorizatzen dira erabaki prozesuak errazteko. Areago arau aurresale klinikoen garapenean ohiko teknika bat da aldagaien kategorizazio hau. Aldagai aurresale bat kategorizatzerakoan kategoria kopurua aldagai aurresale eta erantzulearen arteko erlazioaren menpe dagoenez bi kategoria baino gehiagoren beharra azter...

Metal-bearing nanoparticles (NPs) possess unique physico-chemical characteristics that make them useful for an increasing number of industrial products and applications, but could also confer them a higher toxicity due to their higher reactivity compared to bulk forms of the same materials. There is a considerable interest in the use of in vitro te...

Abstract Increasing the production and applications of TiO2 nanoparticles (NPs) has led to grow concerns about the consequences for the environment. In this study, we investigated the effects of a set of TiO2 NPs on the viability of mussel hemocytes and gill cells using neutral red and thiazolyl tetrazolium bromide assays. For this, we compared the...

CdS quantum dots (QDs) show a great promise for treatment and diagnosis of cancer and for targeted drug delivery, due to their size-tunable fluorescence and ease of functionalization for tissue targeting. In spite of their advantages it is important to determine if CdS QDs can exert toxicity on biological systems. In the present work, cytotoxicity...

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous condition characterized by occasional exacerbations. Identifying clinical subtypes among patients experiencing COPD exacerbations (ECOPD) could help better understand the pathophysiologic mechanisms involved in exacerbations, establish different strategies of treatment, and...

Celebration of The International Year of Statistics was the main reason to organizing the meeting "Statistics in Research vs. Research in Statistics" at the University of the Basque Country UPV/EHU on 2013 October 9th. The goal was to meet statisticians and statistical users from other scientific areas and to discuss about the field. A main confere...

Limited information is available about predictors of short-term outcomes in patients with exacerbations of chronic obstructive pulmonary disease (eCOPD) attending an emergency department (ED). Such information could help stratify these patients and guide medical decision making. The aim of this study was to develop a clinical prediction rule for sh...

To evaluate whether changes in regular physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) affect the rate of hospitalizations for COPD exacerbation (eCOPD). Five hundred forty-three ambulatory clinic patients being treated for COPD were prospectively identified. PA was self-reported by patients, and the level was e...

Objective: To identify factors associated with the development of complications during or after cataract surgery and to determine the effect of complications on improvements in visual acuity and visual function. Design: Longitudinal study. Participants: A total of 4335 patients at 17 hospitals in the Spanish National Health Service undergoing...

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous condition characterized by occasional exacerbations. Identifying clinical subtypes among patients experiencing COPD exacerbations (ECOPD) could help better understand the pathophysiologic mechanisms involved in exacerbations, establish different strategies of treatment, and...

Background In medical practice many, essentially continuous, clinical parameters tend to be categorised by physicians for ease of decision-making. Indeed, categorisation is a common practice both in medical research and in the development of clinical prediction rules, particularly where the ensuing models are to be applied in daily clinical practic...

Purpose: The objective of this study is to analyse the relationship between sociodemographic characteristics of patients undergoing cataract extraction and their outcomes. Methods: The method comprised a prospective cohort study of patients recruited from 17 hospitals of different areas of Spain. Data gathered before surgery included sociodemogr...

The statistical analysis of patient-reported outcomes (PROs) as endpoints has shown to be of great practical relevance. The resulting scores or indexes from the questionnaires used to measure PROs could be treated as continuous or ordinal. The goal of this study is to propose and evaluate a recoding process of the scores, so that they can be treate...

Introduction Our purpose was to assess how pairs of sibling horseshoe bats coexists when their morphology and echolocation are almost identical. We collected data on echolocation, wing morphology, diet, and habitat use of sympatric Rhinolophus mehelyi and R. euryale. We compared our results with literature data collected in allopatry with similar p...

Appendix A. Radio-tracking details of R. mehelyi and R. euryale individuals followed in sympatry; Sex, reproductive status (pregnant females, lactating females), tracking effort (tracking period and active foraging fixes [AFF]), individual foraging home ranges (MCP 100%), and travelled distances (maximum and mean) of radio-tracked R. mehelyi and R....

The climate in Mediterranean ecosystems is characterised by aestival hot temperatures and water shortages which may affect the behaviour of bats living in these environments. We evaluated the influence of habitat type, habitat structure, and water availability on the foraging behaviour of the Mehely’s horseshoe bats (Rhinolophus mehelyi) using clas...

Maedi-Visna (MV) and ovine pulmonary adenocarcinoma (OPA) are two retroviral diseases occurring worldwide that affect adult sheep. Differences in incidence, which may be related to sheep-rearing and housing choices, as well as to genetics, and disease progression have been reported for both diseases. In this work four microsatellites located in imm...

Leaf litter breakdown is a key process, providing matter and energy to communities inhabiting many headwater streams that flow through forests. This detrital pathway is affected by many human landscape transformations; but it is little known about the impact of small headwater reservoirs on leaf litter decay in streams. Alder leaf litter breakdown...

The main purpose of our work was to elucidate factors responsible for the geographical differences in leaf-litter decomposition rates in Spanish oligotrophic headwater streams. Decomposition experiments with alder (Alnus glutinosa) leaf litter were carried out in 22 headwater streams in 4 different climatic regions across the Iberian Peninsula (Cor...

Patients with chronic obstructive pulmonary disease (COPD) often experience exacerbations of the disease that require hospitalization. Current guidelines offer little guidance for identifying patients whose clinical situation is appropriate for admission to the hospital, and properly developed and validated severity scores for COPD exacerbations ar...

Unlabelled: Multidimensional instruments for determining the severity and prognosis of chronic obstructive pulmonary disease (COPD) must be used in daily clinical practice. Objective: To develop and validate a new COPD severity score using variables readily obtained in clinical practice and to compare its predictive capacity with that of other m...

The aim of this study was to develop and validate a new method: a classification and regression tree (CART) based on easily accessible measures to predict mortality in patients with stable chronic obstructive pulmonary disease (COPD). This was a prospective study of two independent prospective cohorts: a derivation cohort with 611 recruited patient...

Rationale: Variability in indications for total hip replacement (THR) and unequal waiting times may limit health care access. Objective: To analyse the relationship between appropriateness and previously developed surgical priority instruments. Method: Multicentre cross-validation study of patients placed on the waiting list for THR. Informati...

The main purpose of our work was to elucidate factors responsible for the geographical differences in leaf-litter decomposition rates in Spanish oligotrophic headwater streams. Decomposition experiments with alder (Alnus glutinosa) leaf litter were carried out in 22 headwater streams in 4 different climatic regions across the Iberian Peninsula (Cor...

Patient-reported outcomes (PRO) are used as primary endpoints in medical research and their statistical analysis is an important methodological issue. Theoretical assumptions of the selected methodology and interpretation of its results are issues to take into account when selecting an appropriate statistical technique to analyse data. We present e...

To develop decision trees based on prospectively collected data for determining the appropriateness of cataract extraction. Prospective observational cohort study. Consecutive patients with a diagnosis of cataract who are on waiting lists to undergo cataract extraction by phacoemulsification. Patients were randomly assigned to 1 of 2 independent co...

Ovine pulmonary adenocarcinoma (OPA) and Maedi-Visna (Maedi) are two chronic respiratory diseases of retroviral origin which occur worldwide. It is known that different host genetic factors influence the outcome of viral infections. To determine if variation in the Mhc-DRB1 gene was associated with progression to these ovine diseases, sheep lungs w...

To study the influence of clinical variables on health-related quality of life (HRQoL) among women with eating disorder (ED) using beta-binomial regression (BBR) to analyze scores on the Short-Form 36 (SF-36) as dependent variable. Female patients diagnosed with ED completed the SF-36 at the beginning of the study and after 2 years of treatment. So...

The prevalence of knee and hip symptoms varies from study to study, or is unknown. The goals of this study were to determine the prevalence of these symptoms, of diagnosed osteoarthritis and the use of prostheses, by age and gender, in a sample of the general older population. We mailed a questionnaire to 11,002 people aged 60 to 90 years who were...

Relatively little is known about the prevalence of knee and hip osteoarthritis in the general population. To estimate the prevalence of knee and hip osteoarthritis and the appropriateness of joint replacement in a general population of older individuals, the validated Knee and Hip OsteoArthritis Screening Questionnaire (KHOA-SQ) was sent to a rando...

To study responsiveness and establish the minimal clinically important differences (MCIDs) and minimal detectable change (MDC) in patients undergoing total knee replacement (TKR) using the Short Form 36 (SF-36) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Prospective observational study in three public hospitals of al...

Health-related quality of life (HRQoL) is an important indicator of health status and the Short Form-36 (SF-36) is a generic instrument to measure it. Multiple linear regression (MLR) is often used to study the relationship of HRQoL with patients' characteristics, though HRQoL outcomes tend to be not normally distributed, skewed and bounded (e.g. b...

To develop a sensitive and specific screening tool for knee and hip osteoarthritis in the general population of elderly people. The Knee and Hip OsteoArthritis Screening Questionnaire (KHOA-SQ) was developed based on previous studies and observed data and sent to 11,002 people aged 60 to 90 years, stratified by age and gender, who were selected by...

A word document containing the variables included in the appropriateness algorithm.

Consensus development techniques were used in the late 1980s to create explicit criteria for the appropriateness of cataract extraction. We developed a new appropriateness of indications tool for cataract following the RAND method. We tested the validity of our panel results. Criteria were developed using a modified Delphi panel judgment process. A...

Methodology based on expert panels has been commonly used to evaluate the appropriateness of interventions. An important issue is the adequate synthesis of the generated information in an applicable way to clinical decision making. This paper shows how statistical procedures help synthesize the results of an expert panel. Three statistical techniqu...

We studied the association between explicit appropriateness criteria for total hip joint replacement (THR) and total knee replacement (TKR) with changes in health-related quality of life of patients undergoing these procedures. Prospective observational study of 1576 consecutive patients with diagnoses of osteoarthritis on waiting lists to undergo...

To study responsiveness and establish the minimal clinically important differences (MCID) and minimal detectable change (MDC) in patients undergoing total hip replacement (THR) using the Short Form 36 (SF-36) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). We conducted a prospective observational study in three publi...

Few studies have assessed the role of sociodemographic characteristics on outcomes after a cholecystectomy. Our goal was to evaluate the influence of age and gender on the health related quality of life (HRQoL) changes after cholecystectomy in this prospective observational study of consecutive patients undergoing cholecystectomy. Patients complete...

The primary goals of this study were to adapt the Short Form-36 (SF-36) questionnaire to the Basque language and to assess the translated questionnaire's psychometric properties. Two pilot studies and a field study were conducted in 1999. The pathologies selected were hypertension, eating disorders, back pain, and HIV infection; blood donors were a...

To evaluate the relationship among appropriateness of the use of cholecystectomy and outcomes. The use of cholecystectomy varies widely across regions and countries. Explicit appropriateness criteria may help identify suitable candidates for this commonly performed procedure. This study evaluates the relationship among appropriateness of the use of...