Russian regional congenital diaphragmatic hernia populational incidence according to the Nationwide Birth Defects Register

Congenital diaphragmatic hernia (CDH) is a severe birth defect characterized by impaired development of the diaphragm that leads to displacement of the abdominal organs into the chest with incidence from 2 to 4 per 10,000 births and its interregional differences that determine the need for assessing the regional incidence. The purpose of this research was to determine the populational CDH incidence and its dynamics in Russia regions based on the data from nationwide epidemiological monitoring of birth defects (BDs). Materials and methods used: the analysis included 2011-2022 data from a cohort study based on BDs epidemiological monitoring from 25 regional registers. In total there were 1493 BD cases among live births, stillbirths and eliminated fetuses with malformations that were included in the study with the total birth count of 5,366,657. Results: the overall CDH incidence in the 25 selected Russia regions was 2.78 per 10,000 births (95% CI 2.71-2.85) without any significant change in its dynamics over the observed period. Interregional differences in CDH incidence were revealed as follows: the maximum incidence of 4.49 (95% CI 3.92-5.06) was registered in the Republic of Sakha (Yakutia); the minimum of 1.23 (95% CI 0.76-1.69) was registered in the Novgorod Oblast. The gender ratio of those affected was 1.2 males per 1 female. The majority of cases (53.81%) were represented by liveborn children, the proportion of stillborns was 5.99%, the proportion of fetuses with diaphragmatic hernia (DH) was 40.2%. 68% were represented by cases of isolated DH v. 32% of a combination of ВР with another BDs among all cases. Conclusion: this study has revealed the CDH incidence rates in 25 selected Russia regions, the incidence variety between the regions with the stability of it in dynamics. Conducting such epidemiological studies is important for understanding the nationwide spread of diseases and identifying risk factors that are important for the prevention and treatment of diseases.