Serum sST2 and MR-ProADM in Pediatric Acute Rheumatic Fever: Diagnostic Value and Association with Carditis Severity

Background Acute rheumatic fever (ARF) remains a leading cause of acquired heart disease in children in developing regions. Early recognition of carditis is pivotal to prevent irreversible valvular damage, yet current diagnostic tools lack sensitivity for myocardial involvement. Novel biomarkers that objectively capture cardiac inflammation and endothelial stress are urgently needed. Soluble suppression of tumorigenicity-2 (sST2) and mid-regional pro-adrenomedullin (MR-ProADM) are emerging cardiovascular indicators linked to fibrosis, hemodynamic load, and vascular dysfunction. This study investigated their diagnostic and prognostic relevance in pediatric ARF. Methods A case–control study included 38 children with ARF and 38 healthy controls. Demographic, clinical, and laboratory data were analyzed. Serum sST2 and MR-ProADM were quantified by ELISA. Nonparametric comparisons and receiver operating characteristic (ROC) analyses were performed. Carditis severity was assessed echocardiographically and categorized as non-to-mild or moderate-to-severe. Results Children with ARF showed markedly higher leukocyte, neutrophil, platelet, and CRP levels (all p < 0.05). Both biomarkers were significantly elevated: sST2 (30.84 ± 36.57 ng/mL vs 7.17 ± 7.43, p = 0.001) and MR-ProADM (0.55 ± 0.09 pmol/mL vs 0.52 ± 0.07, p = 0.046). ROC curves revealed strong diagnostic accuracy for sST2 (AUC = 0.807) and modest performance for MR-ProADM (AUC = 0.666). Both increased stepwise with carditis severity (sST2 p = 0.005; MR-ProADM p = 0.012). Conclusion sST2 and MR-ProADM identify cardiac involvement in pediatric ARF, showing a clear dose-response pattern with disease severity. sST2 emerges as a robust early marker of myocardial stress, while MR-ProADM complements endothelial assessment. Their combined use may advance precision diagnosis and risk stratification in ARF.