The red cell distribution width-to-albumin ratio: A simple index has high predictive accuracy for clinical outcomes in patients with acute pancreatitis

Ongoing research is seeking to identify the best prognostic marker for acute pancreatitis (AP). The purpose of this study was to investigate the role of the red blood cell distribution width-to-albumin ratio (RAR) in the prognosis of AP. This 18-month prospective cohort study was conducted between June 2021 and December 2022 with patients diagnosed with AP. The patients were divided into two groups: severe AP (SAP) and non-severe AP. Factors associated with SAP within the first 48 h of admission were determined. In addition, RAR values at admission and at 48 h (RAR-48th) were calculated, and their ability to predict clinical outcomes was assessed. The primary outcomes were severe disease and in-hospital mortality. Fifty (13.7 %) of 365 patients had SAP. Systemic inflammatory response syndrome, blood urea nitrogen, calcium, and RAR at 48 h after admission were independent predictors of SAP. When RAR-48th was >4.35, the risk of SAP increased approximately 18-fold (OR: 18.59; 95 % CI: 8.58–40.27), whereas no patients with a RAR-48th value of <4.6 died. For in-hospital mortality, the area under the curve (AUC) value of RAR-48th was 0.960 (95 % CI: 0.931–0.989), significantly higher than the AUC values of existing scoring systems. The results of RAR-48th were comparable to those of the other scoring systems with regard to the remaining clinical outcomes. RAR-48th successfully predicted clinical outcomes, particularly in-hospital mortality. Being simple and readily calculable, RAR-48th is a promising alternative to burdensome and complex scoring systems for the prediction of clinical outcomes in AP.