Congenital diaphragmatic hernia in a middle-income country: Persistent high lethality during a 12-year period.

Background: In high- and middle-income countries, mortality associated to congenital diaphragmatic hernia (CDH) is high and variable. In Brazil, data is scarce regarding the prevalence, mortality, and lethality of CDH. This study aimed to analyze, in São Paulo state of Brazil, the temporal trends of prevalence, neonatal mortality and lethality of CDH and identify the time to CDH-associated neonatal death.

Methods: Population-based study of all live births with gestational age ≥ 22 weeks, birthweight ≥400g, from mothers residing in São Paulo State, Brazil, during 2004-2015. CDH definition and its subgroups classification were based on ICD-10 codes reported in the death and/or live birth certificates. CDH-associated neonatal death was defined as death up to 27 days after birth of infants with CDH. CDH prevalence, neonatal mortality and lethality were calculated and their annual percent change (APC) with 95% confidence intervals (95%CI) was analyzed by Prais-Winsten. Kaplan-Meier estimator identified the time after birth that CDH-associated neonatal death occurred.

Results: CDH prevalence was 1.67 per 10,000 live births, with a significant increase throughout the period (APC 2.55; 95%CI 1.30 to 3.83). CDH neonatal mortality also increased over the time (APC 2.09; 95%CI 0.27 to 3.94), while the lethality was 78.78% and remained stationary. For isolated CDH, CDH associated to non-chromosomal anomalies and CDH associated to chromosomal anomalies the lethality was, respectively, 72.25%, 91.06% and 97.96%, during the study period. For CDH as a whole and for all subgroups, 50% of deaths occurred within the first day after birth.

Conclusions: During a 12-year period in São Paulo State, Brazil, CDH prevalence and neonatal mortality showed a significant increase, while lethality remained stable, yet very high, compared to rates reported in high income countries.