Melda DİBEK BÜYÜKDİNÇ, Hatice Sema BAŞAK, Elif ÇELİK, Mücahit AVCİL, Murat TELLİ, Mevlüt TÜRE, Okay BAŞAK

Group A Streptococcal Tonsillopharyngitis: The Diagnostic Power of the Centor and McIsaac Clinical Prediction Models at Different Pre-probability

Background: The power of diagnostic tests is affected by pre-test probability, and clinical prediction models must be validated in different populations. The aim of this study was to determine the diagnostic value of symptoms and signs for group A Streptococcus tonsillopharyngitis and diagnostic power of Centor and Mclsaac criteria in a patient population with different pre-probability. Methods: The study was conducted between September 2019 and February 2020 in Adnan Menderes University Hospital’s outpatient clinics. A total of 405 patients older than 36 months who presented with one of the complaints of acute tonsillopharyngitis participated in the study. Throat swab samples were taken from each patient. The diagnostic value of symptoms and signs was determined by performing univariate analysis and multiple logistic regression analysis. Results: The mean age of 405 patients was 24.7 (3-81 years). While group A Streptococcus positivity was 7.9% over the age of 3, the frequency of group A Streptococcus was 16.8% in children under the age of 15 and 4.7% in adolescents and adults. Group A Streptococcus positivity was 45.8% in those with a Centor score of 4 and 35.7% in those with a Mclsaac score of 4-5. In regression analysis, only 4 criteria included in the Centor score entered the model (P < .05). Conclusions: Centor and McIsaac clinical prediction models were found to be valid in our patient group with low group A Streptococcus positivity. However, although the diagnostic power of both clinical prediction models does not change in the patient population with low group A Streptococcus positivity, they cannot increase the posttest probability above 40-50%.

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1. Aalbers J, O’Brien KK, Chan WS, et al. Predicting Streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor score. BMC Med. 2011;9:67. [CrossRef]
2. Carapetis JR, Steer AC, Mulholland EK, Weber M. The global burden of group A streptococcal diseases. Lancet Infect Dis. 2005;5(11):685- 694. [CrossRef]
3. Worrall G, Hutchinson J, Sherman G, Griffiths J. Diagnosing streptococcal sore throat in adults randomized controlled trial of in-office aids. Can Fam Physician. 2007;53(4):666-671.
4. Worrall GJ. Acute sore throat. Can Fam Physician. 2007;53(11):1961-1962.
5. Fine AM, Nizet V, Mandl KD. Large-scale validation of the Centor and McIsaac scores to predict group A streptococcal pharyngitis. Arch Intern Med. 2012;172(11):847-852. [CrossRef]
6. Chiappini E, Regoli M, Bonsignori F, et al. Analysis of different recommendations from international guidelines for the management of acute pharyngitis in adults and children. Clin Ther. 2011;33(1):48-58. [CrossRef] 7. Matthys J, De Meyere M, van Driel ML, De Sutter A. Differences among international pharyngitis guidelines: not just academic. Ann Fam Med. 2007;5(5):436-443. [CrossRef]
8. Gulliford MC, Dregan A, Moore MV, et al. Continued high rates of antibiotic prescribing to adults with respiratory tract infection: survey of 568 UK general practices. BMJ Open. 2014;4(10):e006245. [CrossRef]
9. McIsaac WJ, White D, Tannenbaum D, Low DE. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. CMAJ. 1998;158(1):75-83.
10. Centor RM. Adolescent and adult pharyngitis: more than strep throat. Arch Intern Med. 2012;172(11):852-853. [CrossRef]
11. Laupacis A, Sekar N, Stiell IG. Clinical prediction rules: a review and suggested modifications of methodological standards. JAMA. 1997;277(6):488-494. [CrossRef]
12. McWhinney’s Textbook of Family Medicine. Thomas Freeman. 4th ed. Sf:203-265.
13. Vittinghoff E, McCulloch CE. Relaxing the rule of ten events per variable in logistic and Cox regression. Am J Epidemiol. 2007;165(6):710- 718. [CrossRef]
14. Centor RM, Witherspoon JM, Dalton HP, Brody CE, Link K. The diagnosis of strep throat in adults in the emergency room. Med Decis Making. 1981;1(3):239-246. [CrossRef]
15. McIsaac WJ, Goel V, To T, Low DE. The validity of a sore throat score in family practice. CMAJ. 2000;163(7):811-815.
16. Cohen JF, Chalumeau M, Levy C, et al. Spectrum and inoculum size effect of a rapid antigen detection test for group A streptococcus in children with pharyngitis. PLoS ONE. 2012;7(6):e39085. [CrossRef]
17. Cohen JF, Cohen R, Levy C, et al. Selective testing strategies for diagnosing group a streptococcal infection in children with pharyngitis: a systematic review and prospective multicentre external validation study. CMAJ. 2015;187(1):23-32. [CrossRef]
18. Centor RM. Adolescent and adult pharyngitis: more than “strep throat”. ArchIntern Med/Vol. 2012;172(11):852-853.
19. Centor RM, Cohen SJ. Pharyngitis management focusing on where we agree. Arch Intern Med. 2006;166(13):1345-1346. [CrossRef]
20. De Meyere EM, Matthys J. Should we expand the pharyngitis paradigm for adolescents and young adults? Ann Intern Med. 2010;152(7):477-8; author reply 478. [CrossRef]