The validity of chief complaint and discharge diagnosis in emergency department-based syndromic surveillance.
OBJECTIVE
Emergency department (ED)-based syndromic surveillance systems are being used by public health departments to monitor for outbreaks of infectious diseases, including bioterrorism; however, few systems have been validated. The authors evaluated a "drop-in" syndromic surveillance system by comparing syndrome categorization in the ED with chief complaints and ED discharge diagnoses from medical record review.


METHODS
A surveillance form was completed for each ED visit at 15 participating Arizona hospitals between October 27 and November 18, 2001. Each patient visit was assigned one of ten clinical syndromes or "none." For six of 15 EDs, kappa statistics were used to compare syndrome agreement between surveillance forms and syndrome categorization with chief complaint and ED discharge diagnosis from medical record review.


RESULTS
Overall, agreement between surveillance forms and ED discharge diagnoses (kappa = 0.55; 95% confidence interval [CI] = 0.52 to 0.59) was significantly higher than between surveillance forms and chief complaints (kappa = 0.48; 95% CI = 0.44 to 0.52). Agreement between chief complaints and ED discharge diagnoses was poor for respiratory tract infection with fever (kappa = 0.33; 95% CI = 0.27 to 0.39). Furthermore, pediatric chief complaints showed lower agreement for respiratory tract infection with fever when compared with adults (kappa = 0.34 [95% CI = 0.20 to 0.47] vs. kappa = 0.44 [95% CI = 0.28 to 0.59], respectively).


CONCLUSIONS
In general, this syndromic surveillance system classified patients into appropriate syndrome categories with fair to good agreement compared with chief complaints and discharge diagnoses. The present findings suggest that use of ED discharge diagnoses, in addition to or instead of chief complaints, may increase surveillance validity for both automated and drop-in syndromic surveillance systems.
Fleischauer
Aaron T
AT
Bioterrorism Preparedness and Response Program, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS C-18, Atlanta, GA 30333, USA. alf6@cdc.gov
Silk
Benjamin J
BJ
Schumacher
Mare
M
Komatsu
Ken
K
Santana
Sarah
S
Vaz
Victorio
V
Wolfe
Mitchell
M
Hutwagner
Lori
L
Cono
Joanne
J
Berkelman
Ruth
R
Treadwell
Tracee
T
D000328:Adult; D000367:Age Factors; D001130:Arizona; D023482:Bioterrorism / Q000517:prevention & control; D002648:Child; D003141:Communicable Diseases / Q000145:classification / Q000175:diagnosis*; D016001:Confidence Intervals; D004636:Emergency Service, Hospital / Q000458:organization & administration*; D006801:Humans; D008499:Medical Records; D015588:Observer Variation; D010351:Patient Discharge; D011159:Population Surveillance / Q000379:methods*; D015203:Reproducibility of Results; D012141:Respiratory Tract Infections / Q000145:classification / Q000175:diagnosis; D013577:Syndrome