Rising Incidence of Syphilitic Uveitis-Related Hospitalizations in the US

The number of syphilis cases continues to increase in the US every year since 2001 with a 74% increase observed since 2017. In addition, there remains a national shortage of injectable penicillin G. Despite the increase in reported cases, to the authors' knowledge, there has been no recent nationwide study investigating the trends in incidence of syphilitic uveitis.

To evaluate the national and regional incidence of syphilitic uveitis-related hospitalizations in the US.

This was a retrospective, cross-sectional study. The Nationwide Inpatient Sample was queried to identify all inpatient admissions with a diagnosis of syphilitic uveitis in the US between the years 2010 and 2019. Analyses were performed to determine baseline sociodemographic characteristics and identify national and regional trends in incidence. All patients hospitalized with a diagnosis of syphilis, uveitis, and/or syphilitic uveitis were eligible for inclusion. Statistical analysis of study data took place in June 2023.

Diagnosis of syphilis, uveitis, and/or syphilitic uveitis on inpatient admissions during the years 2010 to 2019 in the Nationwide Inpatient Sample.

The primary outcome was to determine trends in the national and regional incidence of syphilitic uveitis-related hospitalizations in the US. Secondary outcome measures included sociodemographic characteristics of patients with syphilitic uveitis, incidence stratified by sex and race and ethnicity, and median charge per syphilitic uveitis hospital admission.

From the Nationwide Inpatient Sample, inpatient data from 444 674 patients (median [IQR] age, 53 [37-67] years; 54.8% male) were analyzed. There were an estimated 5581 syphilitic uveitis-related hospitalizations during the 10-year study period. The median (IQR) age of individuals with syphilitic uveitis was 45 (35-55) years, and 4395 patients (78.9%) were male. Syphilitic uveitis disproportionately affected African American individuals (1787 patients [32%], although they compose 13.6% of the population) and those belonging to the lowest median household income quartile (2163 [38.8%]). The national incidence was 0.15 per 100 000 population and showed an increasing trend over the years, with the lowest incidence in 2011 (0.08 per 100 000 population) and the highest incidence in 2019 (0.23 per 100 000 population; P = .04). Regional analysis showed an increase in incidence across all 4 US geographical regions. A total of 1293 patients (23.2%) had comorbid AIDS.

Although this cross-sectional study only captured inpatient diagnosis, an increasing incidence of syphilitic uveitis-related hospitalizations was observed in the US between 2010 and 2019. Given the concomitant national shortage of injectable penicillin G, results suggest that clinicians should maintain a high index of suspicion for syphilis when evaluating patients with intraocular inflammation.