2014.ISDS.Abstracts.Final.pdf


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ISDS 2014 Conference Abstracts

Spatial Distribution of Adolescents with Sexually 
Transmitted Infections Diagnosed in the Pediatric 
Emergency Departments of Washington, DC

Shilpa Patel*1, Lisa Tuchman2, Katie Hayes3, Gia Badolato1, Stephen J. Teach1 and Monika 
K. Goyal1

1Division of Emergency Medicine, Children’s National Medical Center, Washington DC, DC, USA; 2Division of Adolescent Medicine, 
Children’s National Medical Center, Washington DC, DC, USA; 3Division of Emergency Medicine, Children’s Hospital of Philadelphia, 
Philadelphia, PA, USA

Objective
(1) To describe the spatial distribution of adolescents with ED-

diagnosed STIs in a large urban area with a high prevalence of STI
(2) To compare census block groups and identify “hot spots” of STI.

Introduction
Utilization of local surveillance data has been shown to help risk 

stratify patients presenting to the emergency department presenting 
with GAS pharyngitis or meningitis. (1, 2) Adolescents frequently 
present to the emergency department (ED) with symptoms that may 
be associated with a sexually transmitted infection (STI). (3)

When ED providers perceive high local rates of STI and low rates 
of follow-up, empiric treatment is considered. This strategy may result 
in unnecessary treatment. Knowledge of the local spatial distribution 
of adolescents with STIs diagnosed in local pediatric emergency 
departments EDs may enhance risk stratification and allow targeted 
testing and/or treatment among future ED patients in whom STI is 
considered.

Methods
We performed a retrospective cross-sectional medical record 

review of all visits made by District residents aged 13-19 years 
old to the two large urban pediatric EDs in Washington, DC in 
2012 and abstracted demographic and visit data, including STI 
testing results for gonorrhea and chlamydia. Multivariable logistic 
regression was utilized to compare odds of testing positive for STI 
between geographic regions. Geospatial statistical analyses were 
performed using ArcMap 10.1 tools, Hot Spot Analysis and Spatial 
Autocorrelation (Moran’s I).

Results
Of 1002 adolescents tested for STIs, 6.8% tested positive for 

gonorrhea, 18.6% tested positive for chlamydia, 22.7% tested positive 
for either gonorrhea or chlamydia and 2.9% tested positive for co-
infection. The mean age of patients with STIs was 16.9 years (SD 
1.5); 78.4% were female. Of the 227 patients with 1 positive test, 
95% of their addresses were successfully geocoded. Hot Spot Analysis 
indicated statistically significant clusters of STI cases (figure 1.) 
Spatial autocorrelation (Moran’s I) demonstrated that the distribution 
of cases was not random (z-score 13.3, p value < 0.05). The odds of 
adolescent patients from DC Ward 6 testing positive for chlamydia 
was twice that of DC Ward 7(aOR 2.07; 95% CI 1.07 – 3.98).

Conclusions
Geographic analyses identified areas with significantly higher 

cases of ED-diagnosed STIs. Modeling real time surveillance in 
conjunction with other clinical information readily available in 
the electronic medical record may improve prediction of STIs in 
adolescents presenting to the ED, decrease empiric treatment, and 
allow for targeted public health prevention. Incorporation of city-wide 
data could improve our ability to identify clusters of infection.

Figure 1. Hot spot analysis of ED-diagnosed STI cases by census block group 
(n=233)

Keywords
sexually transmitted infection; surveillance; emergency department

Acknowledgments

We would like to thank Drs. Kristen Breslin and James Chamberlain for 
their contribution to study conception and design, Prof. Dante Verme of 
George Washington University for assistance with GIS and the DC GIS 
program and www.census.gov for providing the base maps.

References

(1)Fine AM, Nizet V, Mandl KD. Improved diagnostic accuracy of group 
A streptococcal pharyngitis with use of real-time biosurveillance. Ann 
Intern Med. 2011 Sep 20;155(6):345-52.

(2)Fine AM, Nigrovic LE, Reis BY, Cook EF, Mandl KD. Linking 
surveillance to action: incorporation of real-time regional data into 
a medical decision rule. Am Med Inform Assoc. 2007 Mar-Apr; 
14(2):206-11.

(3)Goyal M, Hayes K, Mollen C. Sexually transmitted infection prevalence 
in symptomatic adolescent emergency department patients. Pediatric 
Emerg Care. 2010 Dec;28(12):1277-80.

*Shilpa Patel

E-mail: shilpapateldas@gmail.com    

Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * 7(1):e154, 2015