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The Cape Town Clinical Decision Rule for Streptococcal Pharyngitis in Children
Mark E Engel1, Karen Cohen, Ronald Gounden
1From the *Department of Medicine, Groote Schuur Hospital and University of Cape Town; and †Division of Clinical Pharmacology, Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa; ‡Division of Medical Microbiology, Department of Pathology, Faculty of Medicine & Health Sciences, Stellenbosch University & NHLS Tygerberg, Tygerberg, South Africa; §College of Public Health & Health Informatics, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia; and ¶Division of Infectious Diseases, Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
Insights
A new clinical decision rule (CDR) for diagnosing group A streptococcal (GAS) pharyngitis in South African children showed improved accuracy. This locally developed rule outperformed existing methods for identifying GAS in children with sore throats.
Area of Science:
- Pediatrics
- Infectious Diseases
- Clinical Diagnostics
Background:
- Existing clinical decision rules (CDRs) for diagnosing group A streptococcal (GAS) pharyngitis lack validation in sub-Saharan Africa.
- This study aimed to develop and evaluate a locally applicable CDR for GAS pharyngitis in South African children.
Purpose of the Study:
- To develop a new, locally relevant clinical decision rule (CDR) for diagnosing group A streptococcal (GAS) pharyngitis.
- To assess the diagnostic performance of existing CDRs in a South African pediatric population.
Main Methods:
- A prospective cohort study enrolled 997 children aged 3-15 with sore throats in primary care clinics.
- Bivariate and multivariate analyses identified key signs and symptoms associated with positive GAS cultures.
- Diagnostic effectiveness of six existing CDRs was evaluated against throat swab cultures.
Main Results:
- 21% of children had a positive GAS culture.
- Tonsillar swelling, exudates, tender anterior cervical lymph nodes, and absence of cough/rhinorrhea were associated with GAS.
- A new 4-variable CDR demonstrated 83.7% sensitivity and 32.2% specificity, outperforming existing rules.
Conclusions:
- A novel 4-variable CDR for GAS pharyngitis, incorporating tonsillar swelling and specific symptoms, is effective in Cape Town children.
- This locally developed CDR offers improved diagnostic accuracy for GAS pharyngitis compared to existing rules in the South African context.
Background:
Existing clinical decision rules (CDRs) to diagnose group A streptococcal (GAS) pharyngitis have not been validated in sub-Saharan Africa. We developed a locally applicable CDR while evaluating existing CDRs for diagnosing GAS pharyngitis in South African children.
Methods:
We conducted a prospective cohort study and enrolled 997 children 3-15 years of age presenting to primary care clinics with a complaint of sore throat, and whose parents provided consent. Main outcome measures were signs and symptoms of pharyngitis and a positive GAS culture from a throat swab. Bivariate and multivariate analyses were used to develop the CDR. In addition, the diagnostic effectiveness of 6 existing rules for predicting a positive culture in our cohort was assessed.
Results:
A total of 206 of 982 children (21%) had a positive GAS culture. Tonsillar swelling, tonsillar exudates, tender or enlarged anterior cervical lymph nodes, absence of cough and absence of rhinorrhea were associated with positive cultures in bivariate and multivariate analyses. Four variables (tonsillar swelling and one of tonsillar exudate, no rhinorrhea, no cough), when used in a cumulative score, showed 83.7% sensitivity and 32.2% specificity for GAS pharyngitis. Of existing rules tested, the rule by McIsaac et al had the highest positive predictive value (28%), but missed 49% of the culture-positive children who should have been treated.
Conclusion:
The new 4-variable CDR for GAS pharyngitis (ie, tonsillar swelling and one of tonsillar exudate, no rhinorrhea, no cough) outperformed existing rules for GAS pharyngitis diagnosis in children with symptomatic sore throat in Cape Town.
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