A Bayesian Logistic Regression approach in Asthma Persistence Prediction

Background: A number of models based on clinical parameters have been used for the prediction of asthma persistence in children. The number and significance of factors that are used in a proposed model play a cardinal role in prediction accuracy. Different models may lead to different significant variables. In addition, the accuracy of a model in medicine is really important since an accurate prediction of illness persistence may improve prevention and treatment intervention for the children at risk. Methods: Data from 147 asthmatic children were analyzed by a new method for predicting asthma outcome using Principal Component Analysis (PCA) in combination with a Bayesian logistic regression approach implemented by the Markov Chain Monte Carlo (MCMC). The use of PCA is required due to multicollinearity among the explanatory variables. Results: This method using the most appropriate models seems to predict asthma with an accuracy of 84.076% and 86.3673%, a Sensitivity of 84.96% and 87.25% and a Specificity of 83.22% and 85.52%, respectively. Conclusion: Our approach predicts asthma with high accuracy, gives steadier results in terms of positive and negative patients and provides better information about the influence of each factor (demographic, symptoms etc.) in asthma prediction

The application of bayesian and frequentist regularization and variable selection methods for the prediction of asthma in later childhood

Asthma is a global health problem and among the most common chronic conditions in childhood. Several models were proposed to predict asthma in children, but their reproducibility in external populations was limited and none was developed to predict asthma in adolescence. I conducted a systematic review of asthma predictive models validated in external populations; validation studies showed poorer predictive performances than development studies. I developed predictive models for asthma between 15 and 20 years, using data from the Study Team for Early Life Asthma Research (STELAR) consortium of five UK asthma cohorts. For one of these cohorts, the Ashford study, I developed an questionnaire to collect follow-up information when study subjects were age 20 years. I harmonised 41 variables across the STELAR cohorts, 39 of which were used as candidate predictors to develop predictive models, while the others were used to define asthma at 15–20 years. Asthma at that age was defined as positive responses to ‘current wheezing’ and ‘asthma medications in the last year’.Two of the five STELAR cohorts (development data) were combined to develop predictive models using stepwise regression and frequentist, Bayesian and empirical Bayes regularization models. The remaining cohorts (validation data) were used to assess predictive performance using discrimination and accuracy measures. Analyses were performed in two populations - all children and a subgroup with reported wheezing between two and five years (high-risk population). Sex, eczema, sensitization to house dust mite and doctor’s diagnosis of asthma in early childhood (4-7 years) were identified as asthma predictors at 15-20 years in both populations. Additional predictors in the general population included early wheezing symptoms and parental allergies, while in the high-risk population maternal allergies and pet in the house at one year were important for asthma prediction in adolescence. Sensitivity was higher in the general population, whereas positive predictive value was higher in the high-risk population. Although accuracy was good in both populations, the predictive ability of the models developed was limited.Open Acces

Comparing predictions made by a prediction model, clinical score, and physicians Pediatric asthma exacerbations in the emergency department

Background: Asthma exacerbations are one of the most common medical reasons for children to be brought to the hospital emergency department (ED). Various prediction models have been proposed to support diagnosis of exacerbations and evaluation of their severity. Objectives: First, to evaluate prediction models constructed from data using machine learning techniques and to select the best performing model. Second, to compare predictions from the selected model with predictions from the Pediatric Respiratory Assessment Measure (PRAM) score, and predictions made by ED physicians. Design: A two-phase study conducted in the ED of an academic pediatric hospital. In phase 1 data collected prospectively using paper forms was used to construct and evaluate five prediction models, and the best performing model was selected. In phase 2, data collected prospectively using a mobile system was used to compare the predictions of the selected prediction model with those from PRAM and ED physicians. Measurements: Area under the receiver operating characteristic curve and accuracy in phase 1; accuracy, sensitivity, specificity, positive and negative predictive values in phase 2. Results: In phase 1 prediction models were derived from a data set of 240 patients and evaluated using 10-fold cross validation. A naive Bayes (NB) model demonstrated the best performance and it was selected for phase 2. Evaluation in phase 2 was conducted on data from 82 patients. Predictions made by the NB model were less accurate than the PRAM score and physicians (accuracy of 70.7%, 73.2% and 78.0% respectively), however, according to McNemar’s test it is not possible to conclude that the differences between predictions are statistically significant. Conclusion: Both the PRAM score and the NB model were less accurate than physicians. The NB model can handle incomplete patient data and as such may complement the PRAM score. However, it requires further research to improve its accuracy

The multimorbidity of asthma and rhinitis: from epidemiologic data to molecular traits

RESUMO: Introdução e Objetivos: A asma afeta a vida de várias centenas de milhões de pessoas de todas as idades, em todo o mundo. Apesar dos avanços nas últimas décadas, a asma e a sua inerente multimorbilidade permanecem um ónus significativo para as pessoas com a doença, para as suas famílias e para a sociedade e economia da saúde. Um número elevado de questões permanece por responder, abrangendo vários aspetos da doença, relacionados com lacunas no conhecimento científico atual, desde a epidemiologia à fisiopatologia e aos cuidados prestados à pessoa com asma. O objetivo principal desta dissertação foi contribuir para a abordagem de algumas destas questões relativas à asma e a sua associação com a rinite. Em particular, os trabalhos originais visavam: (1) estimar a prevalência de asma em Portugal e analisar a sua associação com a rinite em grupos populacionais particularmente vulneráveis e sobre os quais há carência de dados a nível internacional - crianças e idosos; (2) identificar características para um reconhecimento precoce de asma, através de fenótipos clínicos multidimensionais de sibilância recorrente em idade pré-escolar, estabelecidos “sem hipóteses pré-definidas" e relacionados com a persistência de asma na adolescência; (3) analisar a associação entre parâmetros funcionais respiratórios das vias aéreas superiores e inferiores, em conjunto com a avaliação subjetiva do controlo da rinite alérgica e da asma, em crianças em idade escolar; (4) explorar estratégias inovadoras para identificar características metabólicas associadas ao fenótipo de asma e rinite alérgica em crianças, em amostras colhidas de forma não invasiva. Métodos: Esta dissertação baseou-se em três tipos de estudos: 1. Estudos transversais, baseados na população nacional, de cidadãos que viviam em Portugal, tendo sido aplicados questionários por entrevista, usando procedimentos padronizados, para a obtenção de dados epidemiológicos relativos à asma e à rinite. Para o estudo pediátrico, foram analisados os dados de todos os indivíduos com idade inferior a 18 anos que participaram no estudo INAsma (estudo por entrevista telefónica, de base populacional, nacional, para estimar a prevalência de asma em Portugal). O estudo dirigido aos idosos foi desenhado para estimar a prevalência de rinite em adultos com 65 anos ou mais, residentes em Portugal continental, tendo sido os dados colhidos por entrevista direta; 2. Estudo prospetivo de coorte de crianças com idade inferior a 7 anos com sibilância recorrente, avaliadas sistematicamente em pontos de tempo específicos, até 13 anos de seguimento. Foram desenvolvidos modelos de regressão logística multivariável para persistência de asma na adolescência, com base em respostas a questionários e resultados de testes cutâneos por picada. Os fenótipos clínicos foram identificados por análise de agrupamento das variáveis (cluster), selecionadas com base na análise de regressão logística, e comparados a respeito da persistência de asma, uso de tratamentos de controlo e avaliação funcional respiratória em idade escolar e na adolescência; 3. Estudo transversal, caso-controlo, de crianças em idade escolar, com rinite alérgica e asma, e crianças saudáveis (amostra emparelhada para a idade e género), avaliadas no que diz respeito a: - Análise laboratorial funcional respiratória, i.e., avaliações sequenciais do débito inspiratório máximo nasal (PNIF) antes e após a aplicação de vasoconstritor tópico nasal, e espirometria com prova de broncodilatação. O teste de controlo da rinite alérgica e da asma para crianças (CARATkids) foi utilizado para a avaliação subjetiva do controlo destas doenças. As associações entre os parâmetros de avaliação funcional respiratória e de controlo subjetivo foram analisadas usando modelos de regressão linear múltipla. - Análise laboratorial analítica por espectroscopia de ressonância magnética nuclear (NMR) para análise metabolómica não dirigida das amostras de urina e saliva de cada criança. Os dados espectroscópicos e clínicos foram analisados estatisticamente, incluindo abordagens multivariável e univariável. Adicionalmente foram colhidas amostras de condensado de ar exalado (EBC) de voluntários, em conjunto com amostras de ar ambiente da sala de colheitas. As amostras colhidas foram analisadas por NMR, com comparação dos espectros resultantes.Resultados: A prevalência estimada de asma ativa em crianças foi de 8,4% (intervalo de confiança a 95% (95%CI) 6,6%-10,7%). As prevalências estimadas de rinite e de asma diagnosticada por médico em idosos foram 29,8% (95CI% 28,4%-31,3%) e 10,9% (95%CI 9,9%-11,9%), respetivamente. Foi encontrada uma associação forte entre asma e rinite a nível populacional, tanto nas crianças (odds-ratio (OR) 5,2, 95%CI 3,1-8,9), como nos idosos (OR variando de 8,3 95%CI 6,1-11,4 na rinite intermitente ligeira, a 39,9 95%CI 27,5-58,0 na rinite persistente moderada-grave). No estudo de coorte, a presença de atopia e de rinite em idade pré-escolar foram fatores de risco independentes para a persistência de asma na adolescência (OR 11,8 95%CI 4,0-34,6 e OR 10,4 95%CI 3,7-29,1, respetivamente). Foram identificados três fenótipos de sibilância em idade pré-escolar, que foram preditivos para a persistência de asma, uso de medicamentos de controlo e parâmetros funcionais respiratórios em idade escolar e na adolescência. A multimorbilidade, em particular a presença de rinite, com ou sem atopia, associou-se a um pior prognóstico. Na avaliação funcional nasal e pulmonar, observaram-se correlações entre os valores de PNIF pré e pós-vasoconstritor e do débito expiratório máximo instantâneo (PEF) e volume expiratório forçado no primeiro segundo (FEV1), pré e pós-broncodilatação, observado independentemente da presença de rinite e asma. O melhor modelo de regressão linear múltipla para o PNIF incluiu as variáveis PEF, idade e género. Em crianças com rinite alérgica e asma, não foi encontrada associação entre o PNIF e a pontuação no questionário CARATkids, exceto no que diz respeito à obstrução nasal auto-reportada. A análise metabolómica não dirigida em amostras de saliva e urina mostrou um subconjunto de áreas do espetro de NMR significativamente diferente nas crianças com rinite alérgica e asma, em comparação com crianças saudáveis. Alguns metabolitos que contribuíram para estas áreas do espetro foram identificados: arginina, taurina, citrato e aspartato (na saliva), e quinolinato, butirato, pantotenato, gluconato, pseudouridina e lisina (na urina). Observou-se uma correlação entre parâmetros espirométricos e a concentração urinária dos metabolitos quinolinato, butirato e pantotenato, enquanto a dos metabolitos quinolinato, gluconato e pseudouridina estava correlacionada com os níveis de óxido nítrico no ar exalado (FeNO). Observou-se uma associação entre a presença de sensibilização alergénica múltipla e as concentrações urinárias de quinolinato e salivares de citrato e aspartato. O perfil metabólico do EBC foi semelhante à composição espectral do ar ambiente. Discussão e Conclusões: Estes estudos epidemiológicos foram os primeiros de base populacional nacional que reportaram a prevalência de sintomas de asma em todas as idades pediátricas, bem como de sintomas de rinite, sua classificação e associação com asma em idosos. Os resultados reforçaram a asma como uma doença comum em crianças e em idosos, frequentemente associada a rinite. Em crianças com sibilância recorrente em idade pré-escolar, a presença de multimorbilidade, particularmente rinite com ou sem atopia associada, tende a prever um pior prognóstico no que respeita à persistência de asma e compromisso da função respiratória em idade escolar e na adolescência. Estes resultados apoiam a necessidade de uma abordagem integrada da rinite e da asma, desde idades precoces. Para a avaliação funcional respiratória global, o PNIF pode constituir uma medida objetiva complementar à avaliação subjetiva do controlo da rinite alérgica e da asma, em crianças em idade escolar. Os resultados sugerem que na interpretação dos valores do PNIF nesta faixa etária, os valores do PEF devem idealmente ser considerados, para além da idade e do género. A análise metabolómica exploratória de amostras de urina e saliva revelou subconjuntos de áreas do espectro de NMR associadas à rinite alérgica e asma em crianças, gerando novas hipóteses que necessitam de análises suplementares. Os resultados obtidos na análise do perfil metabólico do EBC reforçaram a importância do controlo do ar ambiente durante a colheita de amostras e a necessidade de procedimentos analíticos que permitam distinguir a presença de compostos exógenos nas amostras de EBC. Em resumo, os resultados apresentados nesta dissertação adicionam evidência para uma avaliação global integrada da asma em conjunto com a rinite, tanto na prática clínica, como na investigação. Prevemos que a avaliação funcional nasal possa ser generalizada na prática clínica, numa abordagem global funcional das vias aéreas. O conjunto de metabolitos identificados na análise exploratória metabolómica estimula a continuação dos estudos nesta área para validação dos resultados, seguida da identificação das moléculas/vias metabólicas responsáveis pelas diferenças encontradas, o seu papel na fisiopatologia da rinite alérgica e asma e, por fim, como potenciais (novos) alvos terapêuticos.ABSTRACT: Introduction and Aims: Worldwide and across all age groups, asthma affects the lives of several hundred million people. In spite of the advances over the last decades, asthma and its multimorbidity continue to impart a significant onus on individuals with the disease, their families and society and also on health economies. A high number of unmet needs remain to be resolved, related to gaps in current scientific knowledge covering many aspects of asthma, from epidemiology and pathophysiology to patient care. The main objective of this dissertation was to contribute to address some of these existing unmet needs in asthma and its link with rhinitis. In particular, the original work aimed to (1) estimate nationwide asthma prevalence and analyze its association with rhinitis in particularly vulnerable and internationally data-lacking population groups – the children and the elderly; (2) unveil features for an early recognition of asthma, identifying multidimensional “hypothesis-free” early childhood wheezing clinical phenotypes related to asthma persistence in adolescence; (3) analyze the association between nasal and lower airway function, together with the subjective evaluation of allergic rhinitis and asthma concurrent control in children; (4) explore innovative strategies to uncover “unbiased” differentiating metabolic features of childhood allergic rhinitis and asthma multimorbidity in non-invasively collected samples. Methods: This dissertation was based on three types of studies: 1. Cross-sectional, population-based, nationwide surveys of citizens living in Portugal, applied by interview using standardized procedures, to collect epidemiological data related to asthma and rhinitis and to analyze the association between these two conditions. For the pediatric study, data from all individuals aged below 18 years who participated in the INAsma study (population-based, all-age, nationwide telephone interview study to estimate asthma prevalence in Portugal) was analyzed. The elderly-targeted study was originally designed to estimate rhinitis prevalence in individuals aged 65 years or above living in mainland Portugal and the data was collected by direct face-to-face interview; 2. Prospective cohort study of children aged below 7 years with recurrent wheezing, systematically evaluated at specific time-points, up to 13 years of follow-up. Multivariable logistic regression models for persistent asthma in adolescence were developed based on questionnaires and skin prick tests data. Clinical phenotypes were identified by cluster analysis of variables selected with the logistic regression analysis, and compared for predicting asthma prevalence, use of control treatments and lung function in childhood and adolescence; 3. Cross-sectional, case-control study of school-aged children with allergic rhinitis and asthma multimorbidity and healthy children (matched for age and gender), evaluated with respect to: a. Respiratory functional laboratorial assessments, i.e., sequential assessments of peak nasal inspiratory flow (PNIF) before and after nasal decongestion and spirometry with bronchodilation test. The Control of Allergic Rhinitis and Asthma Test for children (CARATkids) was used for these diseases concurrent subjective control evaluation. Associations between objective and subjective scores were investigated by multiple linear regression models. b. Analytical laboratorial study using untargeted metabolomics analysis by nuclear magnetic resonance (NMR) spectroscopy of urine and saliva samples collected from each child. Spectroscopic and clinical data were subjected to statistical analysis including multivariable and univariable approaches. Additionally, exhaled breath condensate (EBC) samples were collected from volunteers, together with room air samples, which were analyzed by NMR spectroscopy. The resulting spectra were compared.Results: The estimated prevalence of current asthma in children was 8.4% (95% confidence interval (CI) 6.6%-10.7%). The prevalence of rhinitis and of physician-diagnosed asthma in the elderly were estimated to be 29.8% (95%CI 28.4%-31.3%) and 10.9% (95%CI 9.9%-11.9%), respectively. A strong association between asthma and rhinitis at the population-level was found both in children (odds-ratio (OR) 5.2, 95%CI 3.1-8.9) and in the elderly (OR varying from 8.3, 95%CI 6.1-11.4 in mild intermittent rhinitis to 39.9, 95%CI 27.5-58.0 in moderate-severe persistent rhinitis). In the cohort study, atopy and rhinitis at preschool-age were independent risk factors for asthma persistence in adolescence (OR 11.8, 95%CI 4.0-34.6, and OR 10.4, 95%CI 3.7-29.1, respectively). Three distinct early childhood wheezing phenotypes were identified, which were predictive of asthma persistence, use of control treatments and lung function in school-age and adolescence. Multimorbidity, particularly rhinitis, with or without associated atopy, tended to predict a worse prognosis. In the nasal and lung function study, baseline and decongested PNIF correlated with baseline and post-bronchodilation peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1) in school-aged children, observed independently of rhinitis and asthma diagnosis. The best linear regression model for PNIF included the variables PEF, age and gender. In children with allergic rhinitis and asthma, no association was found between PNIF and CARATkids scores, except for nasal obstruction self-report. Untargeted metabolomics analysis of saliva and urine samples revealed a subset of the spectral areas significantly different in the children with allergic rhinitis and asthma, compared to healthy controls. Some metabolites contributing to these variables were identified: arginine, taurine, citrate and aspartate (in saliva), and quinolinate, butyrate, pantothenate, gluconate, pseudouridine and lysine (in urine). Urinary quinolinate, butyrate and pantothenate concentrations correlated with spirometric parameters, while quinolinate, gluconate and pseudouridine concentrations correlated with exhaled nitric oxide (FeNO) levels. Urinary quinolinate and salivary citrate and aspartate were associated with multiple allergenic sensitization. The EBC metabolic profile was found to be highly comparable to the ambient air spectral composition. Discussion and Conclusions: These were the first population-based nationwide epidemiologic studies reporting asthma symptoms prevalence among all pediatric ages, and rhinitis prevalence, its classification and association with asthma in the elderly. Our results further support that asthma is a common disease in children and the elderly, frequently associated with rhinitis. In early childhood, the presence of multimorbidity, particularly rhinitis with or without associated atopy, tended to predict a worse prognosis of recurrent wheezing regarding asthma persistence and impaired lung function in later childhood and adolescence. These results reinforce the need for a global, integrated care pathway in asthma and rhinitis, since early ages. In this integrated assessment, PNIF may provide complementary objective information to subjective concurrent control assessment of allergic rhinitis and asthma in school-aged children. The results suggested that PEF values should ideally be considered, besides age and gender, when interpreting PNIF values in this age group. Exploratory metabolomics revealed differentiating subsets of NMR spectral features in saliva and urine associated with allergic rhinitis and asthma multimorbidity in children, generating hypotheses to be further analyzed. The results obtained in the EBC metabolic profile analysis reinforced the importance of ambient air controls during samples collection and the need for analytical procedures to distinguish exogenously originated metabolites in EBC. In summary, the results presented in this dissertation added compelling information for an integrated, global assessment of asthma together with rhinitis, in clinical practice and in research. We foresee the clinical general application of nasal and lung function evaluation in a global airways assessment strategy. The differentiating subsets of metabolites found in exploratory metabolomics analysis stimulate further studies in order to validate our findings, followed by the identification of molecules/metabolic pathways involved, its role in allergic rhinitis and asthma pathophysiology and ultimately the potential as (novel) therapeutic targets

Associations Between Expressed Emotion, Mental Health, and Functioning in Families: Child Asthma Status as a Moderator

Expressed emotion (EE), the affective attitudes and behaviors of one toward another, can affect caregivers’ behaviors toward their child. Research examining associations between EE and child/family outcomes is mixed; these associations may be affected by other influences such as the presence of a chronic disease or parent mental health. In this study of families living in an urban area, we examined associations between EE and child outcomes (anxiety/depressive symptoms) and family functioning, with parent anxiety as a covariate. We evaluated child asthma status as a moderator as the presence of a chronic illness may strengthen the association between EE and child/family outcomes. Ninety-four children (mean±SD age=8.83±2.03 years, 48.9% female, 92.6% African American; 47 with asthma) and their parents (81.3% annual household income less than $25,000) completed an observational study including interviews and questionnaires. Measures included the Multidimensional Anxiety Scale for Children (MASC), Children’s Depressive Symptoms Inventory (CDI), Self-Report Family Inventory (SFI), Generalized Anxiety Disorder scale (GAD-7), and Five-Minute Speech Sample (FMSS) coded for EE. To examine study aims, regression analyses were conducted using PROCESS macro version 3.4. Asthma status (yes/no) was examined as a moderator. EE was associated with child anxiety symptoms, controlling for parent anxiety symptoms (F(1,70) =7.67, p=0.007). Criticism was also positively associated with asthma control (F(1,39)=4.33, p=.04, R2=.08). Asthma status did not moderate any of the associations. Results suggested that high levels of caregiver EE were associated with child anxiety symptoms, but asthma status did not moderate associations. It is possible that regardless of additional family demands related to asthma, EE is associated with child anxiety. Further examination into other systemic stressors (e.g., poverty, access to care) that may moderate these associations is warranted, as well as the impact that minimizing parent anxiety might have on overall EE