Platelet-neutrophil ratio as a potential biomarker for stroke risk stratification in children and young adults with sickle cell anaemia in resource poor settings

Sickle cell anaemia (SCA) is associated with a significantly increased risk of stroke, primarily assessed using transcranial Doppler ultrasound (TCD). However, access to TCD and haemoglobin F (HbF) testing remains limited in resource-constrained settings. Our preliminary findings identified the platelet-neutrophil ratio (PNR) as a promising biomarker for stroke risk stratification. This updated study evaluates the predictive value of PNR while adjusting for HbF levels and transfusion history. We conducted a retrospective study of 248 HbSS children and young adults at Children’s National Hospital, Washington DC. Demographic, clinical, and hematologic parameters—including PNR, HbF levels, and transfusion status—were analysed in relation to TCD results. Logistic regression and ROC curve analyses were performed. Subjects with abnormal TCD values had significantly lower PNR (53.05 vs. 87.65, p < 0.001) and HbF (7.48% vs. 16.35%, p < 0.001) compared to those with normal TCD results. Transfused children were more likely to have abnormal TCD findings (OR = 5.56, 95% CI: 2.30–13.47, p < 0.001). Multivariate analysis confirmed PNR as a significant independent predictor of abnormal TCD (OR = 0.925, p < 0.001). ROC analysis showed superior predictive performance for PNR (AUC = 0.82) compared to HbF (AUC = 0.73) and ANC (AUC = 0.76). PNR remains a cost-effective and accessible biomarker for stroke risk stratification, retaining its predictive strength even after adjusting for HbF and transfusion status.