A study recently published in JAMA Ophthalmology outlined the national and regional incidence of syphilitic uveitis-related hospitalizations in the United States.
What is syphilitic uveitis?
Syphilitic uveitis is an infectious form of uveitis that can occur at any stage of acquired syphilis—a sexually transmitted infection (STI)—and can result in visual loss if unrecognized or mistreated as a noninfectious ocular inflammation.
Why measure the incidence of syphilitic uveitis?
As reported earlier this month, there has been a spike in the number of syphilis cases in the U.S., with numbers rising tenfold since 2012. More recently, cases have seen a 74% increase since 2017.
Of note, there is a national shortage of injectable penicillin G.
Now, talk about the study.
In this retrospective, cross-sectional study, investigators from Vanderbilt University queried the Nationwide Inpatient Sample database to collect the inpatient data of 444,674 patients (median interquartile range [IQR] age 53 [37-67], 54.8% male) from 2010 to 2019.
All patients hospitalized with a diagnosis of syphilis, uveitis, and/or syphilitic uveitis were eligible for inclusion.
What was the ethnic/racial breakdown of the study cohort?
The self-reported ethnic and racial diversity of patients in the study was as follows:
- White: 40.8%
- African American: 32.0%
- Hispanic or Latino: 15.7%
- Other: 6.8%
- Unknown: 4.7%
Findings?
Over the course of the 10-year study period, there were an estimated 5,581 syphilitic uveitis-related hospitalizations.
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, P=0.04).
Talk about demographic trends.
The median age of patients with syphilitic uveitis was 45 (35-55) years and 4,395 patients (78.9%) were male.
In reference to race/ethnicity, the observed incidence of syphilitic uveitis was:
- African American: 0.4 per 100,000 population
- Hispanic or Latino: 0.15 per 100,000 population
- White: 0.11 per 100,000 population
Tell me more.
As noted above, syphilitic uveitis disproportionately impacted African American individuals (1,787 patients), who made up 32% of hospitalizations.
Researchers also observed this trend for patients belonging to the lowest median household income quartile (2,163 patients [38.8%]).
How did syphilitic uveitis impact different geographical regions?
Regional analyses demonstrated an increase in incidence across all four US geographical regions:
- South: 42.1%
- West: 25.0%
- Northeast: 17.4%
- Midwest: 15.5%
The majority of patients (86.9%) presented to urban teaching hospitals, and the median length of hospital stay was 6 days.
Finally, a total of 1,293 patients (23.2%) had comorbid acquired immunodeficiency syndrome (AIDS).
Limitations?
As the data originated from inpatient hospital treatment, it may underrepresent the clinical impact at the community level.
The study authors mentioned that, according to the International Ocular Syphilis Group survey, initial misdiagnosis was one of the most frequent (63.7%) causes of poor visual outcomes in patients with ocular syphilis.
Take home.
These findings suggest that hospitalizations due to syphilitic uveitis are on the rise, corresponding with an increase in syphilis cases since 2000.
Although this study only captured inpatient diagnosis, it highlights that men, African American patients, those from the South, and low-income individuals are most likely to be affected.
With this—and the shortage of injectable penicillin G—in mind, clinicians would benefit from considering syphilitic uveitis when evaluating patients with intraocular inflammation.