Neutrophil Count and Neutrophil-to-Lymphocyte Ratio Predict Rheumatic Heart Disease in Children With Acute Rheumatic Fever

Background: Acute rheumatic fever (ARF) remains an important cause of acquired heart disease in children, particularly in low- and middle-income countries. Identifying simple and accessible inflammatory markers that reflect disease activity or predict cardiac involvement may improve clinical evaluation. This study aimed to evaluate neutrophil count, neutrophil-to-lymphocyte ratio (NLR), and mean platelet volume (MPV) in pediatric patients with ARF and to assess their potential predictive value for the development of rheumatic heart disease (RHD). Methods: This retrospective study included pediatric patients diagnosed with ARF between June 2015 and July 2020. Clinical, laboratory, and echocardiographic data were obtained from medical records. Hematological parameters, including neutrophil count, lymphocyte count, MPV, and platelet-large cell ratio (P-LCR), were analyzed and compared with those of healthy controls. Patients were followed during routine clinical follow-up to evaluate the development of RHD. Receiver operating characteristic (ROC) curve analysis was performed to assess the predictive value of neutrophil count and NLR. Results: A total of 56 children with ARF and 35 healthy controls were included. Neutrophil count and NLR were significantly higher in patients compared to controls, whereas platelet indices did not differ significantly. A positive correlation was observed between NLR and C-reactive protein (CRP) levels. During follow-up, higher neutrophil counts at diagnosis were associated with persistent valvular involvement. ROC analysis demonstrated moderate predictive performance for neutrophil count (area under the curve (AUC) = 0.72) and NLR (AUC = 0.68) in predicting the development of RHD. Conclusions: Neutrophil count and NLR may reflect inflammatory activity in children with ARF and may help identify patients at risk for developing RHD. However, their predictive value appears to be moderate and should be interpreted with caution. These findings are preliminary and hypothesis-generating, and further prospective studies are needed to confirm these results.