Assessment of Red Blood Cell Distribution Width-to-Platelet Count Ratio as a Prognostic Indicator for Acute Pancreatitis Severity and Outcomes: A Prospective Observational Study

Background Acute pancreatitis (AP) presents with a wide range of severity, from mild to life-threatening disease. Early identification of severe cases is crucial. Traditional prognostic scores such as Ranson's Criteria, Acute Physiology and Chronic Health Evaluation II (APACHE II), and Bedside Index of Severity in Acute Pancreatitis (BISAP) are accurate but complex. The red cell distribution width-to-platelet ratio (RPR), derived from a routine complete blood count (CBC), has emerged as a simple, inexpensive alternative. Methods A prospective observational study was conducted at R.L. Jalappa Hospital and Research Centre, Kolar, from June to August 2025, including 58 adult patients with acute pancreatitis (AP). Red cell distribution width (RDW) and platelet counts were obtained at admission, 48 hours, and 72 hours to calculate the red cell distribution width-to-platelet ratio (RPR). Outcomes, including severity, organ failure, intensive care unit (ICU) stay, and mortality, were analyzed and compared with conventional prognostic scores using receiver operating characteristic (ROC) analysis. Results Of 58 patients, 55.2% had moderate to severe acute pancreatitis (AP) and 6.9% died. Alcohol was the leading etiology (63.8%) and was associated with all mortalities. Mean red cell distribution width-to-platelet ratio (RPR) was significantly higher in non-survivors (0.23) versus survivors (0.052). RPR showed excellent discrimination for mortality (Area Under Curve [AUC] = 0.986; cut-off ≥ 0.13) and severity (AUC = 0.932; cut-off ≥ 0.043) in patients of acute pancreatitis. Persistently elevated RPR correlated with prolonged ICU and hospital stay. Conclusion RPR is a simple, rapid, and cost-effective biomarker for predicting severity and mortality in acute pancreatitis, performing comparably to established scoring systems and suitable for early risk stratification in resource-limited settings.