Aplicación de la regresión polinómica local al análisis discriminante y análisis cluster de series de tiempo

[Resumen]La tesis se centra en el análisis discriminante y análisis cluster de series de tiempo. La preponderancia de este tipo de datos en múltiples áreas de trabajo, como la sismología, economía, física o medicina, entre otras, hacen del análisis discriminante y del análisis clúster de series temporales problemas de gran interés teórico y práctico. SI bien ambas situaciones han sido exhaustivamente estudiadas desde el punto de vista de la teoría multivariante clásica, las características propias de las series temporales hacen que las soluciones desarrolladas para la clasificación de datos estáticos no siempre resulten adecuadas para abordar el proceso de clasificación de procesos estocásticos. En esta tesis se presentan nuevos procedimientos, de corte no paramétrico, para abordar el análisis discriminante y cluster de series temporales en el ámbito espectral. La novedad de estos métodos radica en la utilización de estimadores tipo núcleo, basados en técnicas de regresión polinómica local, para la estimación de la densidad espectral de los procesos sujetos a clasificación. En el contexto del análisis discriminante, se propone un nuevo criterio para la clasificación de series de tiempo, basado en una medida de disparidad definida entre un estimador no paramétrico de la densidad espectral del proceso que se intenta clasificar y la densidad espectral de cada una de las clases de procesos entre las que se discrimina. Para la estimación del espectro se propone utilizar tres estimadores tipo núcleo basados en técnicas de regresión polinómica local. Se demuestra la normalidad asintótica del estadístico discriminante propuesto, y la convergencia a cero de las probabilidades de mala clasificación, tanto en el caso de conocer la densidad teórica de las clases entre las que se discrimina, como en el caso de tener que estimarlas a partir de muestras de entrenamiento

Awake prone decubitus positioning in COVID-19 patients: a systematic review and metaanalysis

Review[Abstract] To date, recommendations for the implementation of awake prone positioning in patients with hypoxia secondary to SARSCoV2 infection have been extrapolated from prior studies on respiratory distress. Thus, we carried out a systematic review and metaanalysis to evaluate the benefits of pronation on the oxygenation, need for endotracheal intubation (ETI), and mortality of this group of patients. We carried out a systematic search in the PubMed and Embase databases between June 2020 and November 2021. A randomeffects metaanalysis was performed to evaluate the impact of pronation on the ETI and mortality rates. A total of 213 articles were identified, 15 of which were finally included in this review. A significant decrease in the mortality rate was observed in the group of pronated patients (relative risk [RR] = 0.69; 95% confidence interval [CI]: 0.480.99; p = 0.044), but no significant effect was observed on the need for ETI (RR = 0.79; 95% CI: 0.631.00; p = 0.051). However, a subgroup analysis of randomized clinical trials (RCTs) did reveal a significant decrease in the need for this intervention (RR = 0.83; 95% CI: 0.710.97). Prone positioning was found to significantly reduce mortality, also diminishing the need for ETI, although this effect was statistically significant only in the subgroup analysis of RCTs. Patients’ response to awake prone positioning could be greater when this procedure is implemented early and in combination with noninvasive mechanical ventilation (NIMV) or highflow nasal cannula (HFNC) therapy

Impact of musculoskeletal pain on health-related quality of life among fishing sector workers

[Abstract] This study aims to determine the impact of musculoskeletal pain (in terms of intensity of the pain, location and functional disability due to back pain) and other factors (socio-demographic, lifestyle and co-morbidity) on the health-related quality of life on a group of shellfish gatherers. This observational transversal study included 929 shellfish gatherers (18–69 years, 98.7 % women) who completed a self-administered questionnaire, including socio-demographic and lifestyle questions, co-morbidity, intensity and location of musculoskeletal pain, and Roland-Morris Disability Questionnaire (RMDQ). Health-related quality of life was assessed using the 36-item Short Form Survey (SF-36). Physical component summary (PCS) and mental component summary (MCS) of the SF-36 were considered as outcome variables. The impact of the different factors on the PCS and MCS scores was evaluated using a stepwise linear regression analysis. Physical health was found to be independently associated to intensity of musculoskeletal pain (regression coefficient, B = −0.96), number of locations with musculoskeletal pain (MSP) (B = −0.77), presence of pain in the hip-knee (B = −2.26), self-reported rheumatic disorders (B = −2.79), lower back pain (B = −1.62) and age (B = −0.06). Mental health was associated with the presence of self-reported depressive syndrome (B = −1043.1) and RMDQ score (B = −42.2). The sample had significantly lower values than the reference population in all of the dimensions of the SF-36. Intensity of the pain, pain in the hip-knee, lower back pain, functional disability due to back pain and number of locations with musculoskeletal pain were found to have a detrimental impact on the physical health of the workers. Depressive syndrome and greater functional disability due to back pain, in turn, predict worse mental health

A model for prediction of in-hospital mortality in patients with subarachnoid hemorrhage

[Abstract] Background: Despite being a rare cause of stroke, spontaneous subarachnoid hemorrhage (SAH) is associated with high mortality rates. The prediction models that are currently being used on SAH patients are heterogeneous, and few address premature mortality. The aim of this study was to develop a mortality risk stratification score for SAH. Methods: A retrospective study was carried out with 536 patients diagnosed with SAH who had been admitted to the intensive care unit (ICU) at the University Hospital Complex of A Coruña (Spain) between 2003 and 2013. A multivariate logistic regression model was developed to predict the likelihood of in-hospital mortality, adjusting it exclusively for variables present on admission. A predictive equation of in-hospital mortality was then computed based on the model's coefficients, along with a points-based risk-scoring system. Its discrimination ability was also tested based on the area under the receiver operating characteristics curve and compared with previously developed scores. Results: The mean age of the patients included in this study was 56.9 ± 14.1 years. Most of these patients (73.9%) had been diagnosed with aneurysmal SAH. Their median length of stay was 7 days in the ICU and 20 days in the general hospital ward, with an overall in-hospital mortality rate of 28.5%. The developed scales included the following admission variables independently associated with in-hospital mortality: coma at onset [odds ratio (OR) = 1.87; p = 0.028], Fisher scale score of 3-4 (OR = 2.27; p = 0.032), Acute Physiology and Chronic Health Evaluation II (APACHE II) score within the first 24 h (OR = 1.10; p < 0.001), and total Sequential Organ Failure Assessment (SOFA) score on day 0 (OR = 1.19; p = 0.004). Our predictive equation demonstrated better discrimination [area under the curve (AUC) = 0.835] (bootstrap-corrected AUC = 0.831) and calibration properties than those of the HAIR scale (AUC = 0.771; p ≤ 0.001) and the Functional Recovery Expected after Subarachnoid Hemorrhage scale (AUC = 0.814; p = 0.154). Conclusions: In addition to the conventional risk factors for in-hospital mortality, in our study, mortality was associated with the presence of coma at onset of the condition, the physiological variables assessed by means of the APACHE II scale within the first 24 h, and the total SOFA score on day 0. A simple prediction model of mortality was developed with novel parameters assessed on admission, which also assessed organ failure and did not require a previous etiological diagnosis

Organ dysfunction as determined by the SOFA score is associated with prognosis in patients with acute traumatic spinal cord injury above T6

Observational study[Abstract] Study design: This is a retrospective, observational study. Objectives: To evaluate organ dysfunction in patients with an acute traumatic spinal cord injury (ATSCI) above T6 using the Sequential Organ Failure Assessment (SOFA) score to determine its association with mortality. Setting: The study was performed at the intensive care unit (ICU) of a tertiary hospital in the northwest of Spain. Methods: The study included 241 patients with an ATSCI above T6 who had been admitted to the ICU between 1998 and 2017. A descriptive analysis of all variables collected was performed to compare the survivors with the non-survivors. In addition, a logistic regression model was used in the multivariate analysis to identify variables that were independently associated with mortality. Results: The results revealed significant differences between the survivors and non-survivors in terms of their age, Charlson Comorbidity Index, Glasgow Coma Scale score on admission, APACHE II score, SOFA score on day 0 and day 4, and delta SOFA 4-0 (ΔSOFA 4-0). The results of this multivariate analysis identified the following variables as independent predictors of intra-ICU mortality: age (OR = 1.05; 95% CI: 1. 01-1.08), SOFA score on day 0 (OR = 1.42; 95% CI: 1.13-1.78), ΔSOFA 4-0 (OR = 1.53; 95% CI: 1.25-1.87), and fluid balance on day 4 (OR = 1.16; 95% CI: 1.00-1.35). Conclusions: The SOFA score is useful for evaluating organ dysfunction in patients with an ATSCI above T6. After adjusting the analysis for conventional variables, organ dysfunction on admission, changes in organ function between day 4 and day 0 (ΔSOFA 4-0), and fluid balance on day 4 were seen to be independently associated with mortality in our study

Calidad de vida relacionada con la salud en trabajadoras del sector pesquero usando el cuestionario SF-36

[Resumen] Objetivo. Determinar la calidad de vida relacionada con la salud (CVRS) mediante el cuestionario SF-36 en trabajadoras del sector pesquero, y compararla con valores normalizados de población de referencia y con valores de otras muestras similares que presentan trastornos musculoesqueléticos. Método. Mediante un estudio transversal se midió la CVRS en 917 mariscadoras a pie seleccionadas a partir de la participación voluntaria en un taller de fisioterapia. Se utilizó un cuestionario autoadministrado que incluía variables sociodemográficas, de estilo de vida, de comorbilidad, de prevalencia de dolor musculoesquelético y de CVRS. Para el SF-36 se calcularon puntuaciones crudas, puntuaciones estandarizadas y puntuaciones z. Resultados. La edad media de las participantes es de 50,6 años (desviación estándar: 8,8). En todas las dimensiones del SF-36 la muestra tuvo valores inferiores que la población general de referencia. Las mayores diferencias se observaron en las personas más jóvenes. Las dimensiones más afectadas, superando la diferencia mínimamente importante, fueron dolor corporal, vitalidad y salud general. Su salud física está más afectada que su salud mental. Conclusiones. Se demuestra que este grupo de trabajadoras tiene peor CVRS que la población general y que otras muestras poblacionales, sobre todo en los componentes físicos.[Abstract] Objective. To determine health-related quality of life (HRQoL) measured with the 36-item Short-Form (SF-36) questionnaire in women workers in the fishing industry, compared with norm-based values in the reference population and other similar samples of persons with musculoskeletal disorders. Method. A cross-sectional study was performed to measure HRQoL in 917 shellfish gatherers. Women taking part in a physiotherapy workshop were invited to participate. We used a self-administered questionnaire, including questions on sociodemographic variables, lifestyle, comorbidity, the prevalence of musculoskeletal disorders, and HRQoL. For the SF-36 raw scores, norm-based scores and z-scores were calculated. Results. The mean age of participants was 50.6 years (standard deviation: 8.8). In all dimensions of the SF-36, values in the sample were lower than in the general reference population. The greatest differences were in younger people. The most affected dimensions were bodily pain, vitality and general health. Physical health was more affected than mental health. Conclusions. HRQoL, especially physical components, was worse in women shellfish gatherers than in the general population and other population samples

Epidemiología y factores de riesgo asociados a displasia broncopulmonar en prematuros menores de 32 semanas de edad gestacional

[Abstract] Objectives. To describe risk factors of bronchopulmonary dysplasia in very preterm infants in the first weeks of life. Material and methods. Retrospective cohort study of preterm infants ≤ 32 weeks of gestational age and birth weight ≤ 1500 g. A multivariate logistic regression analysis was performed to identify independent risk factors for bronchopulmonary dysplasia in the first weeks of life. Results. A total of 202 newborns were included in the study (mean gestational age 29.5 ± 2.1 weeks), 61.4% never received invasive mechanical ventilation. The incidence of bronchopulmonary dysplasia was 28.7%, and 10.4% of the patients were diagnosed with moderate-severe bronchopulmonary dysplasia. Bronchopulmonary dysplasia was independently associated with gestational age (P < 0.001; OR = 0.44 (95% CI = 0.30–0.65)), the need for mechanical ventilation on the first day of life (P = 0.001; OR = 8.13 ((95% CI = 2.41–27.42)), nosocomial sepsis (P < 0.001; OR = 9.51 ((95% CI = 2.99–30.28)) and FiO2 on day 14 (P < 0.001; OR = 1.39 ((95% CI = 1.16–1.66)). Receiving mechanical ventilation at the first day of life (P = 0.008; OR = 5.39 ((95% CI = 1.54–18.89)) and at the third day of life (P = 0.001; OR = 9.99 ((95% CI = 2.47–40.44)) and nosocomial sepsis (P = 0.001; OR = 9.87 ((95% CI = 2.58–37.80)) were independent risk factors for moderate-severe bronchopulmonary dysplasia. Conclusions. Gestational age, mechanical ventilation in the first days of life and nosocomial sepsis are early risk factors for bronchopulmonary dysplasia. The analysis of simple and objective clinical data, allows us to select a group of patients at high risk of bronchopulmonary dysplasia in whom it could be justified to act more aggressively, and shows areas for improvement to prevent its development or reduce its severity.Objetivos. Describir los factores de riesgo de displasia broncopulmonar en las primeras semanas de vida en recién nacidos muy prematuros. Material y métodos. Estudio observacional de cohortes retrospectivo en recién nacidos ≤32 semanas y ≤ 1500 gramos. Se realizó un análisis multivariante de regresión logística para identificar factores de riesgo independientes en las primeras semanas de vida. Resultados. Se incluyeron 202 recién nacidos con una edad gestacional media de 29,5 ± 2,1 semanas. El 61,4% de los pacientes no recibió ventilación mecánica invasiva. El 28,7% fue diagnosticado de displasia broncopulmonar, y el 10,4% de displasia broncopulmonar moderada-grave. La edad gestacional (p < 0,001; OR = 0,44 (95%IC = 0,30–0,65)), la ventilación mecánica en el día 1 (p = 0,001; OR = 8,13 ((95%IC = 2,41–27,42)), la sepsis nosocomial (p < 0,001; OR = 9,51 ((95%IC = 2,99–30,28)) y la FiO2 en el día 14 (p < 0,001; OR = 1,39 ((95%IC = 1,16–1,66)) fueron los factores de riesgo independientes de displasia broncopulmonar. La ventilación mecánica el día 1 (p = 0,008; OR = 5,39 ((95%IC = 1,54–18,89)) y 3 de vida (p = 0,001; OR = 9,99 ((95%IC = 2,47–40,44)) y la sepsis nosocomial (p = 0,001; OR = 9,87 ((95%IC = 2,58–37,80)) se asociaron al desarrollo de displasia broncopulmonar moderada-grave. Conclusiones. La edad gestacional, la ventilación mecánica en los primeros días de vida y la sepsis nosocomial son factores de riesgo precoces de displasia broncopulmonar. El análisis de datos clínicos sencillos y objetivos nos permite seleccionar a un grupo de pacientes con alto riesgo de desarrollar displasia broncopulmonar en el que podría estar justificado actuar de forma más agresiva, y nos muestra áreas de mejora para prevenir su desarrollo o disminuir su gravedad

Identification of predictive factors of the degree of adherence to the Mediterranean diet through machine-learning techniques

[Abstract] Food consumption patterns have undergone changes that in recent years have resulted in serious health problems. Studies based on the evaluation of the nutritional status have determined that the adoption of a food pattern-based primarily on a Mediterranean diet (MD) has a preventive role, as well as the ability to mitigate the negative effects of certain pathologies. A group of more than 500 adults aged over 40 years from our cohort in Northwestern Spain was surveyed. Under our experimental design, 10 experiments were run with four different machine-learning algorithms and the predictive factors most relevant to the adherence of a MD were identified. A feature selection approach was explored and under a null hypothesis test, it was concluded that only 16 measures were of relevance, suggesting the strength of this observational study. Our findings indicate that the following factors have the highest predictive value in terms of the degree of adherence to the MD: basal metabolic rate, mini nutritional assessment questionnaire total score, weight, height, bone density, waist-hip ratio, smoking habits, age, EDI-OD, circumference of the arm, activity metabolism, subscapular skinfold, subscapular circumference in cm, circumference of the waist, circumference of the calf and brachial area.Instituto de Salud Carlos III; PI17/01826Xunta de Galicia; ED431G/01Xunta de Galicia; ED431D 2017/16Xunta de Galicia; ED431D 2017/23Xunta de Galicia; ED431C 2018/4

Colorectal cancer recurrence and its impact on survival after curative surgery: an analysis based on multistate models

[Abstract] Aim: To investigate the usefulness of multistate models (MSM) for determining colorectal cancer (CRC) recurrence rate, to analyse the effect of different factors on tumour recurrence and death, and to assess the impact of recurrence for CRC prognosis. Methods: Observational follow-up study of incident CRC cases disease-free after curative resection in 2006-2013 (n = 994). Recurrence and mortality were analyzed with MSM, as well as covariate effects on transition probabilities. Results: Cumulative incidence of recurrence at 60 months was 13.7%. Five years after surgery, 70.3% of patients were alive and recurrence-free, and 8.4% were alive after recurrence. Recurrence has a negative impact on prognosis, with 5-year CRC-related mortality increasing from 3.8% for those who are recurrence-free 1-year after surgery to 33.6% for those with a recurrence. Advanced stage increases recurrence risk (HR = 1.53) and CRC-related mortality after recurrence (HR = 2.35). CRC-related death was associated with age in recurrence-free patients, and with comorbidity after recurrence. As expected, age≥75 years was a risk factor for non-CRC-related death with (HR = 7.76) or without recurrence (HR = 4.26), while its effect on recurrence risk was not demonstrated. Conclusions: MSM allows detailed analysis of recurrence and mortality in CRC. Recurrence has a negative impact on prognosis. Advanced stage was a determining factor for recurrence and CRC-death after recurrence.info:eu-repo/grantAgreement/ISCIII/Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia/PI18%2F01676/ES/CARACTERIZACIÓN DE GRANDES SUPERIVIENTES EN CANCER COLORRECTAL: APLICACIÓN DE MODELOS DE CURACIÓN PARA LA ESTIMACIÓN DE LA SUPERVIVENCIA A LARGO PLAZOThe cohort in which the study was based was recruited within the framework of a multicenter project who received two other grants from the Ministry of Science and Innovation, Carlos III Institute, Healthcare Research Fund (PI051075 and PS09/0066375)Xunta de Galicia; 08CSA073916P

Sensory processing patterns in developmental coordination disorder, attention deficit hyperactivity disorder and typical development

[Abstract] Background. Sensory processing difficulties (SPD) are present in children with Developmental Coordination Disorder (DCD) and Attention Deficit and Hyperactivity Disorder (ADHD). However, little is known about sensory processing variability in these disorders. Objective. The purpose of this study was to explore SPD among children with DCD, ADHD and co-occurring symptoms in comparison to children with typical development (TD) and to determine how potential social confounders may influence these associations. Methods. The study involved 452 children aged 6–12 years. The Short Sensory Profile-2 was used to assess sensory processing patterns. Multiple linear regressions were utilized to investigate the relationship between DCD, ADHD and co-occurring symptoms and sensory processing patterns, adjusting for social covariates. Results. Children with DCD and ADHD symptoms showed greater variability of atypical sensory processing patterns compared with TD children. Low registration and sensory sensibility issues were more prevalent in the DCD group. ADHD children showed higher rates of low registration, sensory sensibility and sensory seeking, and all children in the co-occurring symptoms group presented sensory sensibility. Conclusion. This study reports significant variability in sensory processing among children with DCD, ADHD and co-occurring symptoms using a population-based sample. These differences can contribute to understand how neurological and social factors correlates across diagnoses.Xunta de Galicia; ED481A-2018/15