Quality of reporting on birth defects in birth certifi cates: case study from a Brazilian reference hospital Qualidade da notifi cação de defeitos congênitos nas declarações de nascido vivo: estudo de caso em hospital de referência no Brasil

The aim of this study was to evaluate the coverage, validity and reliability of Brazil’s Information System on Live Births (SINASC) for birth defects in a hospital in the city of Campinas (São Paulo State). The study population consisted of 2,823 newborn infants delivered in 2004 at the Women’s Integrated Health Care Center (CAISM). A birth defect registry (ECLAMC) was used as the gold-standard. All birth defect cases reported at CAISM in 2004 (92 cases) were selected from SINASC data files. All 168 birth defect cases from the same city and year registered at ECLAMC were also retrieved. An underreporting of 46.8% was observed for all birth defects, and 36.4% when considering only the major birth defects. The ascertained sensitivity and specificity were, respectively, 54.2% and 99.8%. The reliability of three and four-digit ICD-10 coding for birth defects was 0.77 and 0.55 respectively (kappa statistic). These results suggest that information provided by birth certificates in Campinas still presents limitations when seeking to ascertain accurate estimates of the prevalence of birth defects, hence indicating the need for improvements in the SINASC database to enable it to portray birth defect prevalence at birth in this city. Congenital Abnormalities; Birth Certificates; Information Systems Introduction Birth defects have an important public health impact in developing countries. Worldwide 7.6 million children are born each year with a severe genetic disorder or birth defect, close to 95% of them in the developing world, where 80% of the global population lives, contributing significantly to infant mortality 1. In Brazil, the proportion of birth defects in infant mortality, previously obscured by infectious diseases, assumed great relevance with the epidemiologic transition. In 2005, chapter XVII of the International Classification of Diseases 10th revision (ICD-10), namely Congenital Malformations, Deformations and Chromosomal Abnormalities, represented the third leading cause of infant mortality (16.3%) in the first year of life, making evident a clear rise in the proportion of this particular form of mortality in the last 20 years: 7.1% in 1985-1987 and 11.2% in the period 1995-1997 (Departamento de Informática do SUS; http://www.datasus.gov.br, accessed on 18/Jul/2008). In the late 1960s, after the thalidomide episode, the first registries for birth defects were created. The primary reason for this was improved surveillance that would prevent the repetition of a similar tragedy 2. One of the purposes of surveillance is to detect changes in the prevalence of a specific defect or pattern of defects that might indicate the presence of a new causative factor. ARTIGO ARTICLE Luquetti DV, Koifman RJ 1722 Cad. Saúde Pública, Rio de Janeiro, 25(8):1721-1731, ago, 2009 However, the information has also been increasingly used for various other reasons, including epidemiologic studies for the etiology of birth defects, studies of their societal impact, census of disabled people for planning medical services and social welfare provision, assisting the development of clinical genetic services for care and prevention of birth defects, and evaluations of the effectiveness of preventive measures such as the enrichment of flour with folic acid, and the rubella vaccination 3. In Brazil, the Information System on Live Births (SINASC), launched in 1990, has as instrument for data collection, the Birth Certificate, which includes information about maternal, gestation and newborn characteristics. In 1999, a new field named: “Congenital Malformations and/or Chromosomal Anomaly” was introduced. Thus, the basis for the observation of the prevalence at birth of birth defects was established by specific type, geographic unity and period, in a population-based surveillance system. Another information system for birth defects in Brazil is the Latin-American Collaborative Study of Congenital Malformations (ECLAMC), operating since 1967, with a network of 130 hospitals, 36 in Brazil. This system, in the absence of others, serves as the only source of information for the surveillance of this form of morbidity and represents a good quality epidemiological database. Nevertheless, the coverage is only 2% of all Brazilian births and the information generated is hospital-based 4. The information about pregnancies and newborns generated by SINASC has been the object of several validation studies 5,6,7,8. Reliability of birth defects data retrieved from birth certificate data in Rio de Janeiro city was recently evaluated comparing the reports of birth defects from birth certificates with maternal and newborn medical records 9. However, birth defects data still need extensive studies about the quality of the information including validity of data as well as coding reliability in other Brazilian municipalities. This study evaluated the quality of the SINASC information regarding birth defects in Campinas city (Southeast of Brazil), from the Center for Women’s Integrated Health Care (CAISM) at the State University of Campinas (UNICAMP), aiming to evaluate coverage, validity of diagnoses and reliability of birth defects coding. It constitutes the first step of a wider project of evaluation of the Birth Certificate, in hospitals distributed in the Northeast, Southeast and South of Brazil. Methodology This hospital-based study was performed using two data sources, SINASC and ECLAMC. Both systems had independent functioning working teams until 2004 and there was no internal practice for sharing information throughout the birth defect diagnostic and registry processes.