1. PHS / Department of General Practice Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Systematic review of the diagnostic accuracy of signs & symptoms and validation of the Centor Score in predicting group A  -haemolytic streptococcal pharyngitis in adults in Primary Care Jolien Aalbers (Erasmus student), Kirsty O’Brien, Wai-Sun Chan, Borislav D Dimitrov, Conor Teljeur, Gavin Falk, and Tom Fahey

2. PHS / Department of General Practice Group A  -haemolytic streptococcal (GABHS) pharyngitis (‘Strep throat’)  GABHS infection is the principal indication for antibiotic treatment in patients presenting with pharyngitis  Throat swabs can be used to diagnose GABHS pharyngitis, but they are:  expensive  time delay for lab results &  proportion of patients with positive results are carriers  A validated CPR could decrease the number of patients who require further testing and enhance appropriate prescribing of antibiotics in general practice Nasal Cavity Pharynx Palate Larynx Pharynx Nasal Cavity

3. PHS / Department of General Practice Centor Score Any of the following signs and symptoms: 1. Tonsillar exudate 2. Tender cervical anterior adenopathy 3. History of fever (or >38.0  C) 4. Absence of cough 0 – 1 Low No treatment 2 - 3 Intermediate Further testing Rapid antigen detection test (RADT) 4 High Score Probability of GABHS Empirical treatment with antibiotics ACP/ASIM guidelines

4. PHS / Department of General Practice Diagnostic Test Accuracy of Signs and Symptoms

5. PHS / Department of General Practice Results Diagnostic Test Accuracy of signs and symptoms

6. PHS / Department of General Practice Validation of the Centor Score

7. PHS / Department of General Practice Methods Validation of Centor Score  Derivation study (Centor et al 1981) used as predictive model  Results presented as ratio measurement number predicted by Centor Score to have GABHS pharyngitis number reported to have GABHS pharyngitis in each study

8. PHS / Department of General Practice Centor Score Any of the following signs and symptoms: 1. Tonsillar exudate 2. Tender cervical anterior adenopathy 3. History of fever (or >38.0  C) 4. Absence of cough 0 – 1 Low No treatment 2 - 3 Intermediate Further testing Rapid antigen detection test (RADT) 4 High Score Probability of GABHS Empirical treatment with antibiotics ACP/ASIM guidelines

9. PHS / Department of General Practice Score 0-1: Low probability of GABHS Summary statistics: n = 1223 Total predicted events = 60 Total observed events = 87 RR = 0.70 [0.49 – 1.01] Heterogeneity: Chi 2 = 12.6, I 2 = 12%

10. PHS / Department of General Practice Centor Score Any of the following signs and symptoms: 1. Tonsillar exudate 2. Tender cervical anterior adenopathy 3. History of fever (or >38.0  C) 4. Absence of cough 0 – 1 Low No treatment 2 - 3 Intermediate Further testing Rapid antigen detection test (RADT) 4 High Score Probability of GABHS Empirical treatment with antibiotics ACP/ASIM guidelines

11. PHS / Department of General Practice Score 2 – 3: Intermediate probability of GABHS Summary statistics: n = 1439 Total predicted events = 320 Total observed events = 361 RR = 0.98 [0.77 – 1.24] Heterogeneity: Chi 2 = 37.8, I 2 = 63%

12. PHS / Department of General Practice Centor Score Any of the following signs and symptoms: 1. Tonsillar exudate 2. Tender cervical anterior adenopathy 3. History of fever (or >38.0  C) 4. Absence of cough 0 – 1 Low No treatment 2 - 3 Intermediate Further testing Rapid antigen detection test (RADT) 4 High Score Probability of GABHS Empirical treatment with antibiotics ACP/ASIM guidelines

13. PHS / Department of General Practice Score 4: High probability of GABHS Summary statistics: n = 272 Total predicted events = 151 Total observed events = 127 RR = 1.14 [0.95 – 1.37] Heterogeneity: Chi 2 = 15.7, I 2 = 11%

14. PHS / Department of General Practice Summary & Conclusions Diagnostic Test Accuracy of signs and symptoms  All signs and symptoms had only a modest ability to discriminate GABHS from non GABHS pharyngitis patients  A combination of these signs and symptoms is required to accurately differentiate GABHS pharyngitis form non-GABHS pharyngitis Validation of the Centor Score  The Centor Score produces consistent accurate prediction in all score categories  Predicted = observed  The Centor score is a useful tool and could enhance the appropriate prescribing of antibiotics in Primary care

15. PHS / Department of General Practice Acknowledgements  HRB Centre for Primary Care Research  Everyone who provided extra data for the meta- analysis

16. PHS / Department of General Practice Score 2 - 3 intermediate probability of GABHS Summary statistics: Score 2 n = 762 Predicted events = 117 Observed events = 131 RR = 1.00 [0.69 – 1.46] Heterogeneity: Chi 2 = 26.1, I 2 = 50% Score 3 n = 565 Predicted events = 178 Observed events = 184 RR = 0.96 [0.79 – 1.16] Heterogeneity: Chi2 = 14.5, I2 = 11%