Introduction: Inflammatory processes have been proposed to have a role in maintaining the patency of Ductus Arteriosus. Red cell distribution width (RDW) levels escalate in the presence of inflammation. Our aim was to evaluate the role of red cell distribution width to platelet ratio (RPR) in predicting the closure of hemodynamically significant patent ductus arteriosus (hsPDA) in response to paracetamol therapy in preterm neonates. Methods: A prospective comparative study was conducted on preterm neonates less than 37 weeks of gestation diagnosed with hsPDA after obtaining Institutional ethical clearance and detailed informed consent from the parents. All the neonates were treated with oral paracetamol for 3 days and then reassessed for closure of PDA. RDW and platelet counts were analyzed within 24 hours of life and RPR was then calculated. Preterms with sepsis, anemia, asphyxia, major congenital malformations were excluded from the study. Results: 108 preterm neonates were admitted to the NICU during the study period, of which 50 neonates were included in the study. Ductus closed in 28 preterms following treatment by day 3. Mean RPR was found to be lower in the neonates in which the ductus closed by day 3. An RPR cut off of 0.12 having AUC of 0.769 had sensitivity of 68% and specificity of 86% with PPV and NPV of 79% and 77% respectively for the prediction of Ductus Arteriosus closure. Conclusion: Our study shows that RPR can be used as a simple and effective screening tool in foreseeing the successful closure of hsPDA with pharmacotherapy.

Keywords: Ductus Arteriosus; Ductal patency; Paracetamol; Inflammation.