Determinants of death from malformations of the circulatory system

Abstract

Abstract Background Congenital malformations (CMs) were the second cause of death in infants under the age of 1 year in North America and Europe in 2017, behind perinatal causes.Of the CMs, those of the circulatory system (MCSs) were the most lethal. Studies in Brazil, North America and England have reported higher mortality from MCS in the presence of prematurity, non-white skin color of the newborn, asphyxia, low birthweigth, advanced maternal age, and low maternal education level. The magnitudes of those associations vary. Those studies have investigated neither the risk of death from MCS, with control of the mediation provoked by those and other variables, nor the construction of a model to explain the relationship between variables and deaths. Objective To assess the associations of maternal geographic and socioeconomic factors, as well as gestational and birth factors, with deaths from MCSs in the first year of life in Brazil from 2006 to 2016, and to build an explanatory model of the relationship between variables and death. Methods Study of the Brazilian databases Information System on Live Births and Mortality Information System, which were linked by deterministic relationship and submitted to the cohort strategy. Crude and controlled relative risks were estimated. Acyclic graphs directed the creation of explanatory models of the relationship between maternal and fetal variables and the risks of death from MCSs and all causes. Results The deterministic linkage of 32,011,727 live birth certificates and 266,215 deaths yielded 248,027 linked pairs. Low birth weight (RR=14.38), asphyxia in the first (RR=5.95) and fifth minute (RR=11.86), maternal age ≥35 years (RR=1.66), male sex (RR=1.13), residing in the West-Central Brazil (RR=1.22) and small number of prenatal visits (RR=2.24) increased the risk of death from MCSs. Prematurity and multiple-gestation pregnancy had effects on death mediated by low birth weight and asphyxia regardless of the cause of death. Maternal education level and skin color did not increase the risk of death from MCS but influenced deaths from other causes. Conclusion The explanatory model of the relation of maternal geographic and socioeconomic, gestational and birth factors with deaths in the first year of life in Brazil from 2006 to 2016 showed that the small number of prenatal visits, male sex, low birthweigth, and presence of asphyxia in the first and fifth minutes are variables with a direct effect on the risk of death regardless of the cause of death. Deaths from MCSs in the West-Central regions and maternal age ≥35 years pose a higher risk of death, but this effect was not evidenced for other causes of death. Better gestational care with an adequate number of prenatal visits would enable the early diagnosis of MCSs with proper life support and treatment. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Federal University of Rio de Janeiro