Purpose <p>Pancreatoduodenectomy (PD) is a complex surgery with a high rate of postoperative complications, for which effective preoperative indicators are currently lacking. Inflammatory indices such as the pan-immune-inflammation value (PIV), platelet-neutrophil product (PPN), and platelet-albumin ratio (PAR) have shown potential as biomarkers for postoperative prognosis in various cancers. However, their predictive value for complications in open-PD (OPD) patients remains underexplored. This study aims to investigate the relationship between these inflammatory indices and postoperative complications, identify new preoperative biomarkers, and provide a theoretical basis for improving perioperative management in OPD patients.</p> Methods <p>We analyzed data from 309 patients who underwent open-PD (OPD). Six preoperative inflammatory indices—platelet-to-lymphocyte ratio (PLR), PIV, PPN, PAR, neutrophil-to-HDL ratio (NHR), and neutrophil-albumin ratio (NAR)—were assessed for their association with postoperative complications using logistic regression and restricted cubic spline analysis. Predictive performance was evaluated with ROC curves and decision curve analysis.</p> Results <p>PLR, PIV, and PPN were significantly linked to most outcomes and had good predictive performance. NHR was associated with severe complications. PAR effectively predicted hemorrhage (AUC = 0.684) and delayed gastric emptying (DGE) (AUC = 0.701). Combining indices enhanced predictive accuracy.</p> Conclusions <p>PLR, PIV, and PPN are key preoperative indicators for OPD patients, with PAR also useful for predicting complications like hemorrhage and DGE.</p>