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

Minor psychiatric disorders in mothers and asthma in children

Recent studies have shown that asthma represents a major health issue not only in children of developed countries but also in urban centers in some middle-income countries. Brazil has one of the highest prevalences of asthma worldwide. Recently, interest has grown in the relationship between psychosocial factors and asthma. This article examines the relationship between maternal mental disorders and the prevalence of asthma in low-income children from an inner city area of Salvador in the state of Bahia, Brazil, and is part of the SCAALA program (Social Change, Allergy and Asthma in Latin America). A total of 1,087 children between the ages of 5 and 12 were investigated, together with their mothers. The mothers' mental health was evaluated using the SRQ-20, an instrument for the psychiatric screening of minor psychiatric disorders (depression, anxiety and somatic complaints). The prevalence of asthma was investigated using the ISAAC survey, a standardized, validated questionnaire for asthma and other allergic diseases. Cases were defined as asthma if the patient reported having had wheezing in the previous 12 months in addition to at least one of the following: having asthma, wheezing while exercising, waking during the night because of wheezing, or having had at least four episodes of wheezing in the previous 12 months. Atopy was defined as a positive skin prick test to allergens. The presence of minor psychiatric disorders in the mothers was significantly associated with the presence of asthma in the children, and this association was consistent with all forms of asthma, irrespective of whether it was atopic or nonatopic. Future studies should be carried out to further investigate this association and the potential biological mechanisms involved. Programs for asthma control should include strategies for stress reduction and psychological support for the families of asthmatic children

A genome-wide association study of asthma symptoms in Latin American children

© 2015 Costa et al.Background: Asthma is a chronic disease of the airways and, despite the advances in the knowledge of associated genetic regions in recent years, their mechanisms have yet to be explored. Several genome-wide association studies have bee

The centre for data and knowledge integration for health (CIDACS): Linking health and social data in Brazil

The Centre for Data and Knowledge Integration for Health (CIDACS) was created in 2016 in Salvador, Bahia-Brazil with the objective of integrating data and knowledge aiming to answer scientific questions related to the health of the Brazilian population. This article details our experiences in the establishment and operations of CIDACS, as well as efforts made to obtain high-quality linked data while adhering to security, ethical use and privacy issues. Every effort has been made to conduct operations while implementing appropriate structures, procedures, processes and controls over the original and integrated databases in order to provide adequate datasets to answer relevant research questions. Looking forward, CIDACS is expected to be an important resource for researchers and policymakers interested in enhancing the evidence base pertaining to different aspects of health, in particular when investigating, from a nation-wide perspective, the role of social determinants of health and the effects of social and environmental policies on different health outcomes