Joint analysis of longitudinal and survival AIDS data - a Bayesian perspective

Presented at The One-day Workshop on Spatial-Temporal Models in Epidemiology and Health. Faculdade de Ciências da Universidade de Lisboa, 20 June 2014.Research was partially supported by the projects PTDC/MAT/118335/2010 and FCT Pest-OE/MAT/UI0006/2011

Contribution for new genetic markers of rheumatoid arthritis activity and severity : sequencing of the tumor necrosis factor-alpha gene promoter

© 2007 Fonseca et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe objective of this study was to assess whether clinical measures of rheumatoid arthritis activity and severity were influenced by tumor necrosis factor-alpha (TNF-alpha) promoter genotype/haplotype markers. Each patient's disease activity was assessed by the disease activity score using 28 joint counts (DAS28) and functional capacity by the Health Assessment Questionnaire (HAQ) score. Systemic manifestations, radiological damage evaluated by the Sharp/van der Heijde (SvdH) score, disease-modifying anti-rheumatic drug use, joint surgeries, and work disability were also assessed. The promoter region of the TNF-alpha gene, between nucleotides -1,318 and +49, was sequenced using an automated platform. Five hundred fifty-four patients were evaluated and genotyped for 10 single-nucleotide polymorphism (SNP) markers, but 5 of these markers were excluded due to failure to fall within Hardy-Weinberg equilibrium or to monomorphism. Patients with more than 10 years of disease duration (DD) presented significant associations between the -857 SNP and systemic manifestations, as well as joint surgeries. Associations were also found between the -308 SNP and work disability in patients with more than 2 years of DD and radiological damage in patients with less than 10 years of DD. A borderline effect was found between the -238 SNP and HAQ score and radiological damage in patients with 2 to 10 years of DD. An association was also found between haplotypes and the SvdH score for those with more than 10 years of DD. An association was found between some TNF-alpha promoter SNPs and systemic manifestations, radiological progression, HAQ score, work disability, and joint surgeries, particularly in some classes of DD and between haplotypes and radiological progression for those with more than 10 years of DD.This work was supported by grant POCTI/SAU-ESP/59111/2004 from Fundação Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

Predictors of mortality in HIV-associated hospitalizations in Portugal: a hierarchical survival model

<p>Abstract</p> <p>Background</p> <p>The beneficial effects of highly active antiretroviral therapy, increasing survival and the prevention of AIDS defining illness development are well established. However, the annual Portuguese hospital mortality is still higher than expected. It is crucial to understand the hospitalization behaviour to better allocate resources. This study investigates the predictors of mortality in HIV associated hospitalizations in Portugal through a hierarchical survival model.</p> <p>Methods</p> <p>The study population consists of 12,078 adult discharges from patients with HIV infection diagnosis attended at Portuguese hospitals from 2005–2007 that were registered on the diagnosis-related groups' database.</p> <p>We used discharge and hospital level variables to develop a hierarchical model. The discharge level variables were: age, gender, type of admission, type of diagnoses-related group, related HIV complication, the region of the patient's residence, the number of diagnoses and procedures, the Euclidean distance from hospital to the centroid of the patient's ward, and if patient lived in the hospital's catchment area. The hospital characteristics include size and hospital classification according to the National Health System. Kaplan-Meier plots were used to examine differences in survival curves. Cox proportional hazard models with frailty were applied to identify independent predictors of hospital mortality and to calculate hazard ratios (HR).</p> <p>Results</p> <p>The Cox proportional model with frailty showed that male gender, older patient, great number of diagnoses and pneumonia increased the hazard of HIV related hospital mortality. On the other hand tuberculosis was associated with a reduced risk of death. Central hospital discharge also presents less risk of mortality.</p> <p>The frailty variance was small but statistically significant, indicating hazard ratio heterogeneity among hospitals that varied between 0.67 and 1.34, and resulted in two hospitals with HR different from the average risk.</p> <p>Conclusion</p> <p>The frailty model suggests that there are unmeasured factors affecting mortality in HIV associated hospitalizations. Consequently, for healthcare policy purposes, hospitals should not all be treated in an equal manner.</p

Análise Bayesiana espacial conjunta de dados longitudinais e de sobrevivência com aplicação ao estudo do VIH/SIDA no Brasil

Comunicação apresentada no XX Congresso da Sociedade Portuguesa de Estatística. Porto 26 a 29 de Setembro de 2012."A análise conjunta dos dados longitudinais e de sobrevivência tem suscitado muito interesse nos últimos anos, especialmente para dados relativos ao VIH/SIDA. Tradicionalmente, estes dados eram analisados considerando separadamente o tempo-até-evento (análise de sobrevivência) e as medições repetidas de biomarcadores (análise longitudinal). Mas, tendo em conta que os dados são observados num mesmo indivíduo, a modelação conjunta das respostas subjacentes parece ser mais apropriada. O modelo conjunto espacial bayesiano aqui proposto apresenta melhorias consideráveis nas distribuições do tempo mediano de sobrevivência quando comparado com o modelo separado.

Time Series Analysis of Deaths Due to Diarrhoea in Children in Rio de Janeiro, Brazil, 1980-1998

Diarrhoea is still a considerable public-health problem in developing countries, especially among children aged less than five years. The well-known relationship between seasonal variation and aetiological agents of diarrhoeal diseases helps inform the decisions about the prevention and control measures. The aim of this study was to identify the temporal patterns of deaths due to diarrhoea in children, aged less than five years, in Rio de Janeiro State from 1980 to 1998. The study analyzed data on monthly deaths due to diarrhoea; the data were supplied by the Natural Mortality Information System (NMIS, Ministry of Health of Brazil). Auto Regressive Integrated Moving Average modelling was applied to the data. Using this model, the huge decline and the winter peaks could be highlighted, and they may express the predominance of rotavirus as the aetiology of diarrhoeal deaths, suggesting that an effective vaccine is the main measure for the prevention and control of severe diarrhoea

Associações entre escolaridade, renda e Índice de Massa Corporal em funcionários de uma universidade no Rio de Janeiro, Brasil: estudo Pró-Saúde

O objetivo deste estudo foi investigar a associação entre escolaridade e renda com o Índice de Massa Corporal (IMC). Nestas análises, foram estudados 3.963 funcionários de uma universidade no Rio de Janeiro, Brasil, participantes da fase 1 de um estudo longitudinal (Estudo Pró-Saúde). Para testar as diferenças entre os subgrupos, utilizaram-se análise de variâncias, teste de Wald e modelos lineares generalizados. A prevalência de obesidade variou inversamente com o nível educacional, especialmente entre as mulheres (p < 0,001). Nas análises de regressão múltipla, observou-se que, entre os homens, a educação e a renda familiar per capita não foram associadas com maior IMC. Entre as mulheres, a educação, mas não a renda, foi significativa e inversamente associada com IMC mais elevado (p < 0,001). Assim, a baixa escolaridade exerce um papel importante na determinação social da obesidade, principalmente entre mulheres

Estresse no trabalho e interrupção de atividades habituais, por problemas de saúde, no Estudo Pró-Saúde

Queixas relativas à saúde têm sido mais freqüentemente associadas a problemas no trabalho do que a qualquer outro aspecto da vida, incluindo problemas financeiros ou familiares. Nesse estudo, investigamos a associação entre estresse no trabalho e a interrupção das atividades habituais por problemas de saúde. Esta investigação, do tipo transversal, se insere em um estudo prospectivo de 2.343 funcionários técnico-administrativos de uma universidade no Estado do Rio de Janeiro - Estudo Pró-Saúde. Procederam-se as análises multivariadas valendo-se dos modelos lineares generalizados e assumindo-se uma distribuição binomial e função de ligação logarítmica. Os homens em atividades com alta exigência apresentaram prevalência da interrupção das atividades habituais duas vezes maior do que aqueles cujas atividades não foram classificadas nessa categoria (baixa exigência; ativo; passivo), ajustando-se por idade (RP = 2,06; IC95%: 1,54-2,76). Entre as mulheres, a prevalência do desfecho foi 45% maior (RP = 1,45; IC95%: 1,17-1,79)

Matching-Adjusted Indirect Comparison of Efficacy and Consumption of rVIII-SingleChain Versus Two Recombinant FVIII Products Used for Prophylactic Treatment of Adults/Adolescents with Severe Haemophilia A.

Given the relatively small number of patients with haemophilia A, head-to-head comparisons between recombinant FVIII (rFVIII) products are difficult to conduct. This study compared the efficacy and consumption of rVIII-SingleChain (lonoctocog alfa, AFSTYLA®) with rAHF-PFM (octocog alfa, Advate®) and rFVIIIFc (efmoroctocog alfa, Elocta®), for the prophylaxis and treatment of bleeding episodes in previously treated adolescents/adults with severe haemophilia A, through a matching-adjusted indirect comparison (MAIC). A systematic literature review identified published clinical trials for rAHF-PFM and rFVIIIFc. Individual patient data for rVIII-SingleChain were used to match baseline patient characteristics to those from published trials, using an approach similar to propensity score weighting. After matching, annualized bleeding rates (ABR), percentage of patients with zero bleeds, and rFVIII consumption were compared across trial populations. Published data were identified from two rAHF-PFM trials and one rFVIIIFc trial. rVIII-SingleChain had similar ABR (risk ratio [RR]: 0.74 [0.16; 3.48]; RR: 1.18 [0.85; 1.65]) and percentage of patients with zero bleeds (odds ratio [OR]: 1.34 [0.56; 3.22]; OR: 0.78 [0.47; 1.31]) versus rAHF-PFM and rFVIIIFc, respectively. Annual rVIII-SingleChain consumption was significantly lower than rAHF-PFM (mean difference: - 1507.66 IU/kg/year [- 2011.71; - 1003.61]) and equivalent to rFVIIIFc (RR: 0.96 [0.62; 1.49]). Although limited to published information for comparator trials, these results suggest that with an annualized rFVIII consumption comparable to rFVIIIFc, but significantly lower than rAHF-PFM, routine prophylaxis with rVIII-SingleChain is able to maintain a similar ABR and percentage of patients with zero bleeds, attesting to the long-acting nature of rVIII-SingleChain