Abstract
This study examines the impact of congenital syphilis incidence trends on congenital heart surgery outcomes in Brazil, with a focus on mortality rates, treatment costs, and length of hospital stay. Using an ecological study design, we analyzed nationwide data from 2007 to 2023 to identify regional and temporal patterns in these relationships. The results revealed significant increases in the incidence of syphilis across all regions, accompanied by marked disparities in healthcare resource allocation and surgical capacity. The Northeast and Southeast regions demonstrated expansion in approved surgeries, while the North and South regions exhibited comparatively slower growth, highlighting inequities in specialized care access. Correlation analyses identified a moderate negative association between syphilis incidence and mortality rate, and a strong negative correlation between cost per surgery and mortality. Our regression model explained 44.2% of the variance in mortality rates, with syphilis incidence, cost per surgery, and length of hospital stay emerging as significant predictors. Machine learning validation confirmed the predominance of linear relationships, with Linear Regression (R (2) = 0.513) outperforming Random Forest (R (2) = 0.321). These findings highlight the need for targeted interventions to address regional disparities and optimize resource allocation, offering evidence-based guidance to policymakers and healthcare providers to improve neonatal health outcomes in Brazil.