Evaluation of record linkage of two large administrative databases in a middle income country: stillbirths and notifications of dengue during pregnancy in Brazil

BACKGROUND: Due to the increasing availability of individual-level information across different electronic datasets, record linkage has become an efficient and important research tool. High quality linkage is essential for producing robust results. The objective of this study was to describe the process of preparing and linking national Brazilian datasets, and to compare the accuracy of different linkage methods for assessing the risk of stillbirth due to dengue in pregnancy. METHODS: We linked mothers and stillbirths in two routinely collected datasets from Brazil for 2009–2010: for dengue in pregnancy, notifications of infectious diseases (SINAN); for stillbirths, mortality (SIM). Since there was no unique identifier, we used probabilistic linkage based on maternal name, age and municipality. We compared two probabilistic approaches, each with two thresholds: 1) a bespoke linkage algorithm; 2) a standard linkage software widely used in Brazil (ReclinkIII), and used manual review to identify further links. Sensitivity and positive predictive value (PPV) were estimated using a subset of gold-standard data created through manual review. We examined the characteristics of false-matches and missed-matches to identify any sources of bias. RESULTS: From records of 678,999 dengue cases and 62,373 stillbirths, the gold-standard linkage identified 191 cases. The bespoke linkage algorithm with a conservative threshold produced 131 links, with sensitivity = 64.4% (68 missed-matches) and PPV = 92.5% (8 false-matches). Manual review of uncertain links identified an additional 37 links, increasing sensitivity to 83.7%. The bespoke algorithm with a relaxed threshold identified 132 true matches (sensitivity = 69.1%), but introduced 61 false-matches (PPV = 68.4%). ReclinkIII produced lower sensitivity and PPV than the bespoke linkage algorithm. Linkage error was not associated with any recorded study variables. CONCLUSION: Despite a lack of unique identifiers for linking mothers and stillbirths, we demonstrate a high standard of linkage of large routine databases from a middle income country. Probabilistic linkage and manual review were essential for accurately identifying cases for a case-control study, but this approach may not be feasible for larger databases or for linkage of more common outcomes

Perinatal health outcomes of international migrant women in Brazil: A nationwide data linkage study of the CIDACS birth cohort (2011-2018).

BACKGROUND: We investigated perinatal outcomes among live births from international migrant and local-born mothers in a cohort of low-income individuals in Brazil. METHODS: We linked nationwide birth registries to mortality records and socioeconomic data from the CIDACS Birth Cohort and studied singleton live births of women aged 10-49 years from 1st January 2011 to 31st December 2018. We used logistic regressions to investigate differences in antenatal care, adverse pregnancy outcomes, and neonatal (i.e., ≤28 days) mortality among international migrants compared to non-migrants in Brazil; and explored the interaction between migration, race/ethnicity and living in international border municipalities. RESULTS: We studied 10,279,011 live births, of which 9469 (0.1 %) were born to international migrants. Migrant women were more likely than their Brazilian-born counterparts to have a previous foetal loss (ORadj: 1.16, 1.11-1.22), a delayed start of antenatal care (i.e., beyond 1st trimester) (1.22, 95%CI:1.16-1.28), a newborn who is large for gestational age (1.29, 1.22-1.36), or a newborn with congenital anomalies (1.37, 1.14-1.65). Conversely, migrant women were less likely to deliver prematurely (0.89, 0.82-0.95) or have a low birth weight infant (0.74, 0.68-0.81). There were no differences in neonatal mortality rates between migrants and non-migrants. Our analyses also showed that, when disparities in perinatal outcomes were present, disparities were mostly concentrated among indigenous mothers in international borders and among live births of Black mothers in non-borders. CONCLUSION: Although live births of international migrants generally have lower rates of adverse birth outcomes, our results suggest that indigenous and Black migrant mothers may face disproportionate barriers to accessing antenatal care

Stroke Correlates in Chagasic and Non-Chagasic Cardiomyopathies

BACKGROUND: Aging and migration have brought changes to the epidemiology and stroke has been shown to be independently associated with Chagas disease. We studied stroke correlates in cardiomyopathy patients with focus on the chagasic etiology. METHODOLOGY/PRINCIPAL FINDINGS: We performed a cross-sectional review of medical records of 790 patients with a cardiomyopathy. Patients with chagasic (329) and non-chagasic (461) cardiomyopathies were compared. There were 108 stroke cases, significantly more frequent in the Chagas group (17.3% versus 11.1%; p<0.01). Chagasic etiology (odds ratio [OR], 1.79), pacemaker (OR, 2.49), atrial fibrillation (OR, 3.03) and coronary artery disease (OR, 1.92) were stroke predictors in a multivariable analysis of the entire cohort. In a second step, the population was split into those with or without a Chagas-related cardiomyopathy. Univariable post-stratification stroke predictors in the Chagas cohort were pacemaker (OR, 2.73), and coronary artery disease (CAD) (OR, 2.58); while atrial fibrillation (OR, 2.98), age over 55 (OR, 2.92), hypertension (OR, 2.62) and coronary artery disease (OR, 1.94) did so in the non-Chagas cohort. Chagasic stroke patients presented a very high frequency of individuals without any vascular risk factors (40.4%; OR, 4.8). In a post-stratification logistic regression model, stroke remained associated with pacemaker (OR, 2.72) and coronary artery disease (OR, 2.60) in 322 chagasic patients, and with age over 55 (OR, 2.38), atrial fibrillation (OR 3.25) and hypertension (OR 2.12; p = 0.052) in 444 non-chagasic patients. CONCLUSIONS/SIGNIFICANCE: Chagas cardiomyopathy presented both a higher frequency of stroke and an independent association with it. There was a high frequency of strokes without any vascular risk factors in the Chagas as opposed to the non-Chagas cohort. Pacemaker rhythm and CAD were independently associated with stroke in the Chagas group while age over 55 years, hypertension and atrial fibrillation did so in the non-Chagas cardiomyopathies

USING INDUCTIVE SERIES FEEDBACK TO STABILIZE A MICROWAVE DISTRIBUTED-AMPLIFIER WITH HIGH-GAIN FETS - A NEW DESIGN APPROACH

Numerical results are presented to show how series inductive feedback between the source of the FET and ground, in a common-source configuration, can stabilize a hybrid distributed amplifier. This kind of feedback is useful when using high transconductance FETs. Finally, for a 0.3 x 200-mum HEMT (NEC 321) in chip form, an unconditionally stable four-section distributed amplifier is designed using the suggested feedback, without compromising the gain-bandwidth product.6956456

Experimentally validated two dimensional numerical model for the solidification of PCM along a horizontal long tube

This paper presents the results of a numerical study validated by experimental measurements on the solidification of PCM along a horizontal tube by using the boundary immobilization technique. The two dimensional model (r,z) of the phase change problem is formulated based on the energy equation and the Landau transform which transforms the moving irregular interfaces to fixed parallel interfaces. The finite volume method is used to discretize the system of equations and the associated boundary and initial conditions. A computer program was elaborated and the time and space grids were optimized to make the numerical solution insensitive to the grid size. The model was validated against experimental and numerical results available in the literature and good agreement was found. Additional results were obtained and the numerical predictions were found to agree well with the new measurements showing that the immobilization technique is adequate to handle phase change problems. (c) 2013 Elsevier Masson SAS. All rights reserved.7518419

Impact of cognitive performance on the functional capacity of an elderly population in Natal, Brazil Impacto do desempenho cognitivo na capacidade funcional em uma amostra populacional de idosos do nordeste brasileiro

Functional incapacity and cognitive impairment are conditions related to the process of human aging. Cognitive impairment is considered an important predicitve factor for functional impairment in elderly populations. This cross-sectional study analyzes the association between cognitive performance and functional capacity in an elderly population sample in Natal, Brazil. A total of 213 elderly persons were assessed by the BOAS Multidimensional Questionnaire (Brazil Old Age Schedule) and the Mini-Mental State Examination (MMSE). The results of multivariate analysis and linear regression showed that age and schooling level are factors associated with cognitive performance in the elderly of this study. The final explicative model, elaborated by logistic regression, found that cognitive performance was the only predicitve variable of functional incapacity for the activities of daily living even when adjusted for sociodemographic variables.<br>A incapacidade funcional e o déficit cognitivo são condições relacionadas com o processo de envelhecimento humano. O déficit cognitivo é considerado um importante fator preditor de prejuízos funcionais em populações idosas. Este estudo transversal analisa a associação do desempenho cognitivo na capacidade funcional de uma amostra populacional idosa residente em Natal-RN. Foram avaliados 213 idosos pelo Questionário Multidimensional-BOAS e pelo Mini-Exame do Estado Mental (MEEM). Através de analise multivariada mediante regressão linear, os resultados apontam a idade e o nível de escolaridade como fatores associados ao desempenho cognitivo nos idosos do estudo. O modelo explicativo final elaborado através de regressão logística apresentou o desempenho cognitivo como a única variável preditora de incapacidade funcional para as atividades da vida diária mesmo quando ajustado por variáveis sócio-demográficas

Inflammation enhances the risks of stroke and death in chronic chagas disease patients.

Ischemic strokes have been implicated as a cause of death in Chagas disease patients. Inflammation has been recognized as a key component in all ischemic processes, including the intravascular events triggered by vessel interruption, brain damage and repair. In this study, we evaluated the association between inflammatory markers and the death risk (DR) and stroke risk (SR) of patients with different clinical forms of chronic Chagas disease. The mRNA expression levels of cytokines, transcription factors expressed in the adaptive immune response (Th1, Th2, Th9, Th17, Th22 and regulatory T cell), and iNOS were analyzed by realtime PCR in peripheral blood mononuclear cells of chagasic patients who exhibited the indeterminate, cardiac, digestive and cardiodigestive clinical forms of the disease, and the levels of these transcripts were correlated with the DR and SR. Cardiac patients exhibited lowermRNA nexpression levels of GATA-3, FoxP3, AHR, IL-4, IL-9, IL-10 and IL 22 but exhibited higher expression of IFN-γ and TNF-α compared with indeterminate patients. Digestive patients showed similar levels of GATA-3, IL-4 and IL-10 than indeterminate patients. Cardiodigestive patients exhibited higher levels of TNF-α compared with indeterminate and digestive patients. Furthermore, we demonstrated that patients with high DR and SR exhibited lower GATA-3, FoxP3, and IL-10 expression and higher IFN-γ, TNF-α and iNOS mRNA expression than patients with low DR and SR. A negative correlation was observed between Foxp3 and IL-10 mRNA expression and the DR and SR. Moreover, TNF-α and iNOS expression was positively correlated with DR and SR. Our data suggest that an inflammatory imbalance in chronic Chagas disease patients is associated with a high DR and SR. This study provides a better understanding of the stroke pathobiology in the general population and might aid the development of therapeutic strategies for controlling the morbidity and mortality of Chagas disease