Congenital Syphilis in Live Births: Adverse Outcomes, Hospital Length of Stay, and Costs.

Objective: To examine temporal trends and risk factors for congenital syphilis in newborn hospitalizations and to evaluate the association between adverse outcomes and congenital syphilis and health care utilization for newborn hospitalizations complicated by congenital syphilis.

Methods: We conducted a retrospective, cross-sectional study using data from the National Inpatient Sample to identify newborn hospitalizations in the United States between 2016 and 2020. Newborns with congenital syphilis were identified with International Classification of Diseases, Tenth Revision, Clinical Modification codes. Adverse outcomes, hospital length of stay, and hospital costs were examined. The annual percent change was calculated to assess congenital syphilis trend. A multivariable Poisson regression model with robust error variance was used to examine the association between congenital syphilis and adverse outcomes. Adjusted relative risks (RRs) with 95% CIs were calculated. A multivariable generalized linear regression model was used to examine the association between congenital syphilis and hospital length of stay and hospital costs. Adjusted mean ratios with 95% CIs were calculated.

Results: Of 18,119,871 newborn hospitalizations in the United States between 2016 and 2020, the rate of congenital syphilis increased over time (annual percent change 24.6%, 95% CI, 13.0-37.3). Newborn race and ethnicity, insurance, household income, year of admission, and hospital characteristics were associated with congenital syphilis. In multivariable models, congenital syphilis was associated with preterm birth before 37 weeks of gestation (adjusted RR 2.22, 95% CI, 2.02-2.44) and preterm birth before 34 weeks of gestation (adjusted RR 2.39, 95% CI, 2.01-2.84); however, there was no association with low birth weight or neonatal in-hospital death. Compared with newborns without congenital syphilis, hospital length of stay (adjusted mean ratio 3.53, 95% CI, 3.38-3.68) and hospital costs (adjusted mean ratio 4.93, 95% CI, 4.57-5.32) were higher among those with congenital syphilis.

Conclusion: Among newborn hospitalizations in the United States, the rate of congenital syphilis increased from 2016 to 2020. Congenital syphilis was associated with preterm birth, longer hospital length of stay, and higher hospital costs.