An evidence-based scoring system to diagnose acute rheumatic fever with carditis in children.

Backgound: Acute rheumatic fever (ARF) with carditis and chronic rheumatic heart disease (RHD) may be difficult to differentiate and may lead to missed diagnosis of carditis. We aimed to determine differences between these groups and to develop a new scoring system for this purpose.
Methods: Children (N = 514; mean age 11.6 ± 2.8, range 5-18 years; 65% males) enrolled in a RHD registry at a tertiary care centre were studied. Clinical, laboratory and echocardiographic features of acute rheumatic carditis group (N = 126) were compared with chronic RHD group (N = 388). We performed multiple regression analysis and then developed a new scoring system using independent predictors. Accuracy of this scoring system was assessed using receiver operating characteristic (ROC) curve analysis.
Results: Patients with ARF and carditis were younger, more commonly had history of fever, arthritis/arthralgias and had worse NYHA class. On echocardiography, severity of mitral regurgitation, presence of mitral leaflet nodules, mitral valve prolapse and pericardial effusion were more common in ARF group. On multiple regression analysis, following features were found to be independently predictive of ARF with carditis: age -negative association, NYHA class, severity of mitral regurgitation, mitral leaflet nodules, erythrocyte sedimentation rate and antistreptolysin titer. Based on these 6 variables, a new scoring system (0-13) was developed. A score of 5 or more was found to be best threshold for diagnosis of carditis (ROC AUC 0.87, sensitivity 76%, specificity 79%).
Conclusion: A new scoring system based on independent statistical associations appears promising for differentiating ARF with carditis from chronic RHD.
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