Identifying Patients at Lowest Risk for Streptococcal Pharyngitis: A National Validation Study

Area of Science:

• Pediatric infectious diseases
• Clinical decision support
• Epidemiology of respiratory infections

Background:

• Group A Streptococcus (GAS) pharyngitis is common in children.
• Differentiating viral illness from GAS pharyngitis can be challenging.
• Over-testing for GAS contributes to antibiotic overuse.

Purpose of the Study:

• To determine the prevalence of viral illness features in children tested for GAS pharyngitis.
• To develop a decision rule for identifying low-risk patients with viral illness who may avoid GAS testing.

Main Methods:

• Retrospective study of 67,127 electronic health records from retail health clinics.
• Analysis of patients aged 3-21 years evaluated for sore throat.
• Development of a decision tree algorithm to identify low-risk GAS patients.

Main Results:

• 54% of patients presented with features of viral illness.
• A decision rule identified patients without tonsillar exudates, aged 11+, and lacking fever or cervical adenopathy as low-risk for GAS.
• This low-risk group represented 19% of all patients tested for GAS.

Conclusions:

• An objective decision rule can identify patients with viral illness features at low risk for GAS.
• Improved identification can optimize GAS testing and antibiotic prescribing for pharyngitis.
• This approach supports appropriate use of laboratory diagnostics in pediatric sore throat evaluations.