Uso de um modelo de regressão logistica e tecnicas de diagnostico na identificação de fatores de risco em partos pelvicos

Orientador: Flavio Celso BartmannDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Ciencia da ComputaçãoResumo: Não informado.Abstract: Not informed.MestradoMestre em Estatístic

Modelo aditivo de aalen: uma aplicação para dados de sinusite em pacientes com aids

Em estudos de sobrevivência, as vezes, o interesse não é apenas na distribuição do tempo de falha. É comum a comparação de tempos de sobrevivência de dois ou mais grupos bem como a verificação do efeito de covariáveis na resposta tanto em engenharia quanto, principalmente, em situações clínicas. A maneira mais eficiente de incorporar o efeito desses fatores no estudo é utilizar um modelo estatístico de regressão. Freqüentemente em estudos de sobrevivência o efeito das covariáveis de interesse pode variar ao longo dotempo de duração do estudo. Estas covariáveis são denominadas de dependentes do tempo e a inclusão delas na análise pode fornecer resultados mais precisos. Aalen propôs um modelo de risco aditivo que apresenta vantagens práticas quando as covariáveis são acompanhadas ao longo do tempo e os seus valores podem ser modificados durante o estudo. A principal vantagem desse modelo é que através de análise gráfica é possível verificar mudanças no tempo na influência de cada uma das covariáveis. Isto é, análises com este modelo fornecem informações detalhadas a respeito da influência temporal de cada covariável. Dessa forma o modelo aditivo de Aalen é apresentado neste trabalho com o objetivo de mostrar a sua importância na presença de covariáveis dependentes do tempo. Um banco de dados real envolvendo pacientes infectados pelo HIV e o tempo até o desenvolvimento de sinusite é utilizado para ilustrar o ajuste deste modelo.En el análisis de supervivencia, a veces, el interés no es sólo la distribución del tiempo de fallo. Es habitual comparar los tiempos de supervivencia de dos o más grupos así como la verificación del efecto de covariables en la respuesta, especialmente en situaciones de ingeniería y en los estudios clínicos. La Los efectos de las covariables general se incorporan en el análisis mediante el uso de un modelo de regresión. Por otra parte, en algunas situaciones reales, las covariables pueden ser monitoreados y medidos a lo largo del período de seguimiento. Estas se denominan covariables dependientes del tiempo e incluirlas en el análisis puede proporcionar resultados más exactos. Aalen propuso un modelo de riesgo aditivo que tiene ventajas prácticas cuando las covariables son seguidas en el tiempo y sus valores pueden ser modificados durante el estudio. La principal ventaja de este modelo es que a través de análisis gráfico es posible verificar los cambios en el tiempo de la influencia de cada una de las covariables. Es decir, el análisis con este modelo proporciona información detallada acerca de la influencia temporal de cada covariable. Así, el modelo Aalen aditivo se presenta en este documento con el fin de mostrar su importancia en la presencia de covariables dependientes del tiempo. Una base de datos real de pacientes infectados por VIH y el tiempo para el desarrollo de la sinusitis se utiliza para ilustrar el ajuste del modelo aditivo de Aalen.In survival analysis sometimes the interest is not just on the failure time distribution function. It is common treatment comparisons as well as studying the effect of covariates in the response. This fact happens in engineering and clinical studies. Covariates effects are usually incorporated in the analysis by using a regression model. Moreover, in some real situations, covariates may be monitored and measured along the follow-up period. These covariates are known as time-dependent covariates. Analysis that include these covariates can be more reliable. Aalen proposed an additive risk model that is very attractive. This model has showed some practical advantages especially when the covariates effects varies in time. The main advantage of this model it is that through graphical analysis it is possible to verify changes in the time in the influence of each one of the covariates. That is, analyses with this model supply information detailed regarding the secular influence of each covariate. This model is presented in this paper in terms of time-dependent covariates. A real data set related to HIV patients and time to develop sinusitis is used to illustrate the fit of the additive Aalen model

Effect of combining multiple micronutrients with iron supplementation on Hb response in children: systematic review of randomized controlled trials

Objectives To study the effect of combining multiple (two or more) micronutrients with Fe supplementation on Hb response, when compared with placebo and with Fe supplementation, in children.Data sources Electronic databases, personal files, hand search of reviews, bibliographies of books, and abstracts and proceedings of international conferences.Review methods Randomized controlled trials evaluating change in Hb levels with interventions that included Fe and multiple-micronutrient supplementation in comparison to placebo alone or Fe alone were analysed in two systematic reviews.Results Twenty-five trials were included in the review comparing Fe and micronutrient supplementation with placebo. The pooled estimate (random effects model) for change in Hb with Fe and micronutrient supplementation (weighted mean difference) was 0·65 g/dl (95 % CI 0·50, 0·80, P &lt; 0·001). Lower baseline Hb, lower height-for-age Z score, non-intake of ‘other micronutrients’ and malarial non-hyperendemic region were significant predictors of greater Hb response and heterogeneity. Thirteen trials were included in the review comparing Fe and micronutrient supplementation with Fe alone. The pooled estimate for change in Hb with Fe and micronutrient supplementation (weighted mean difference) was 0·14 g/dl (95 % CI 0·00, 0·28, P = 0·04). None of the variables were found to be significant predictors of Hb response.Conclusions Synthesized evidence indicates that addition of multiple micronutrients to Fe supplementation may only marginally improve Hb response compared with Fe supplementation alone. However, addition of ‘other micronutrients’ may have a negative effect. Routine addition of unselected multiple micronutrients to Fe therefore appears unjustified for nutritional anaemia control programmes.<br/

Mortality, TB/HIV co-infection, and treatment dropout: predictors of tuberculosis prognosis in Recife, Pernambuco State, Brazil

This non-concurrent cohort study aims to identify predictors of tuberculosis mortality in a large population database in Brazil. Tuberculosis, death, and TB/HIV cases were validated respectively from the tuberculosis surveillance (SINAN/TB), mortality (SIM), and SINAN/AIDS databases for a five-year period. Analysis included proportional hazard models with relative risk estimates. Out of 5,451 individuals reported with tuberculosis, 320 (5.9%) died (incidence and mortality rates of 98.6 and 12.2/100 thousand inhabitants, respectively). After adjustment, relative risk of dying from tuberculosis was 9.8 for individuals > 50 years of age; 9.0 for TB/HIV co-infection; 3.0 for mixed TB clinical presentation; and 2.0 for treatment dropout. In the multivariate model, using cases with HIV/AIDS, all adjusted predictors lost significance except mixed clinical presentation (RR 1.9; 1.1-3.1). TB/HIV co-infection is an important predictor of TB mortality. However, among individuals without HIV/AIDS, mortality is still highly associated with older age, mixed clinical forms, and treatment dropout

Esquistossomose mansoni experimental murina: estabilidade da eliminação dos ovos nas fezes e sua associação com a carga parasitária na fase inicial da infecção

Stability of faecal egg excretion and correlation with results related to worm burden at the initial phase of schistosomiasis mansoni were observed in two groups of mice infected with different Schistosoma mansoni cercarial burdens, by means of analysis of quantitative parasitological studies and schistosome counts after perfusion. Thus, it may be stated that few quantitative parasitological stool examinations could be sufficient to express the infection intensity at the initial phase, on the same grounds that it was already demonstrated at the chronic phase. Furthermore, it is confirmed that the use of the number of eggs passed in the faeces as a tool to estimate the worm burden at the initial phase of schistosome infection is adequate.Através da análise de exames parasitológicos quantitativos seriados e da contagem de esquistossomos após perfusão em dois grupos de camundongos infectados com diferentes cargas de cercárias de Schistosoma mansoni, verificou-se a existência da estabilidade da eliminação de ovos e sua correlação com a carga parasitária na fase inicial da esquistossomose mansoni. Deste modo, pode-se afirmar que poucos exames parasitológicos de fezes quantitativos podem ser suficientes para traduzir a intensidade da infecção também na fase inicial , à semelhança do já demonstrado para a crônica. Além disto, comprova-se a adequação do uso do número de ovos eliminados nas fezes como expressão da carga parasitária na fase inicial da infecção esquistossomótica

Assessing the Influence of Different Comorbidities Indexes on the Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in a Developing Country.

Although the application of Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI) has enabled better prediction of transplant-related mortality (TRM) in allogeneic hematopoietic stem cell transplants (AHSCT), data from developing countries are scarce. This study prospectively evaluated the HCT-CI and the Adult Comorbidity Evaluation (ACE-27), in its original and in a modified version, as predictors of post-transplant complications in adults undergoing a first related or unrelated AHSCT in Brazil. Both bone marrow (BM) and peripheral blood stem cells (PBSC) as graft sources were included. We analyzed the cumulative incidence of granulocyte and platelet recovery, sinusoidal obstructive syndrome, acute and chronic graft-versus-host disease, relapse and transplant-related mortality, and rates of event-free survival and overall survival. Ninety-nine patients were assessed. Median age was 38 years (18-65 years); HCT-CI ≥ 3 accounted for only 8% of cases; hematologic malignancies comprised 75.8% of the indications for AHSCT. There was no association between the HCT-CI or the original or modified ACE-27 with TRM or any other studied outcomes after AHSCT. These results show that, in the population studied, none of the comorbidity indexes seem to be associated with AHSCT outcomes. A significantly low frequency of high-risk (HCT-CI ≥ 3) in this Brazilian population might justify these results