Presentation is loading. Please wait.

Presentation is loading. Please wait.

Divisional Meeting 15 th January 2009 Streptococcal Pharyngitis: A Systematic Review of the Predictive Value of Signs and Symptoms and the External Validation.

Similar presentations


Presentation on theme: "Divisional Meeting 15 th January 2009 Streptococcal Pharyngitis: A Systematic Review of the Predictive Value of Signs and Symptoms and the External Validation."— Presentation transcript:

1 Divisional Meeting 15 th January 2009 Streptococcal Pharyngitis: A Systematic Review of the Predictive Value of Signs and Symptoms and the External Validation of the Centor Score CPR By Jolien Aalbers University of Nijmegen

2 Outline Background Methods 1. Diagnostic accuracy of signs and symptoms 2. Validation of the Centor Score Results 1. Diagnostic accuracy of signs and symptoms 2. Validation of the Centor Score

3 Background Group A β-haemolytic Streptococcal (GABHS) pharyngitis can lead to serious complications GABHS infection is the only indication for treatment with antibiotics Antibiotic resistance is an important public health issue A prediction rule to reduce unnecessary antibiotic prescriptions would help to decrease antibiotic resistance

4 Clinical prediction rule “A tool that quantifies the contribution of symptoms, clinical signs and available diagnostic tests to stratify patients according to the probability of having a target disorder” “The outcome can have a diagnostic, prognostic or therapeutic value”

5 Levels of evidence for the development of a CPR

6 The Centor Score 4 items: 1. Tonsillar exudate 2. Tender cervical anterior adenopathy 3. History of fever (or >38.0  C) 4. Absence of cough Cumulative score (0-4 points): % (post-test probabilities)1. 6.5% ( ) % ( ) % ( ) %

7 Other diagnostic tests Throat swab: “gold” standard Takes hours for results Expensive A proportion of patients with positive cultures are carriers Rapid Antigen Detection Test (RADT): Not as sensitive as the throat swab Possible lack of cost-effectiveness

8 Study methods (1) Search strategy: PubMed, EMBASE, Cochrane database, Google Scholar and MEDION Hand-checking references of filtered papers Inclusion and exclusion-criteria: Population: participants were recruited upon 1 st presentation from an ambulatory care setting with sore throat as their main presenting complaint, and had to be at least 15 years of age or older

9 Study methods (2) Study design: the studies had to assess either the diagnostic accuracy of signs and symptoms and/or apply the Centor score Reference standard: a throat swab Retrospective and prospective studies were included No criteria were set for the size of the population Quality assessment: modified QUADAS tool (QUality Assessment of Diagnostic Accuracy Studies)

10 Methods (3): data extraction and analysis of diagnostic accuracy of signs and symptoms Signs and symptoms: Exudate Absence of cough Fever (>38.0  C) Tender Adenopathy Adenopathy Data extraction from: 2x2 tables Analysis with: likelihood ratios, ROC-curves, probability nomogram I²-index for heterogeneity Where heterogeneity is acceptable, likelihood ratios can be pooled

11 Methods (4): data extraction and analysis of validation of the Centor score Predicted versus observed Forest plots – using Random effect model I²-index for heterogeneity Prevalence correction

12 Results (1) 340 potentially relevant articles 16 studies included - 16 studies: signs and symptoms: 3371 patients - 11 studies: validation of the Centor score: 1603 patients Large variability in prevalence: 4.7% %

13 Positive likelihood ratios Sign of “any exudates” Pooled Positive LR = 1.95 (1.63 – 2.32) I² = 74.2% (heterogeneity)

14 Negative likelihood ratios Sign of “Absence of cough” Pooled Negative LR = 0.59 (0.50 – 0.69) I² = 22.7% (heterogeneity)

15 Results (2): Diagnostic accuracy of signs and symptoms Very heterogeneous results No powerful likelihood ratios Conclusion: no sign or symptom on its own is powerful enough to rule in or rule out the diagnosis of streptococcal pharyngitis

16 Results (3): Validation of the Centor score The Centor score four items: 1. Tonsillar exudate 2. Tender cervical anterior adenopathy 3. History of fever (or >38.0  C) 4. Absence of cough Each item gets 1 point. Score: 0-4 points

17 Forest plot for Centor score 0-1 I² = 5% of heterogeneity Z = 2.77, P = 0.006

18 Forest plot for Centor score 2-3 I² = 62% of heterogeneity Z = 1.15, P = 0.25

19 Forest plot for Centor score 4 I² = 7% of heterogeneity Z = 1.33, P = 0.18

20 Prevalence correction Centor Score 1 Adjusted for pooled prevalence of 21.9%

21 Results (4): Validation of the Centor score Conclusions: Heterogeneity is acceptable Underprediction for Centor score 0-1 No significant difference between predicted and observed values in Centor score 2-4 Underprediction in studies with a higher prevalence and overprediction in studies with a lower prevalence, compared with Centors’ prevalence Correction with a pooled prevalence is possible


Download ppt "Divisional Meeting 15 th January 2009 Streptococcal Pharyngitis: A Systematic Review of the Predictive Value of Signs and Symptoms and the External Validation."

Similar presentations


Ads by Google