NHR is a novel independent predictor of moderate-severe or severe HTG-AP, with the highest tertile conferring a 6.03-fold increased risk (95% CI: 2.98-12.19; P < 0.001) and an AUC of 0.701 for MSAP+SAP prediction. SII, MHR, SIRI, and AISI provide complementary prognostic value, supporting early risk stratification using NHR (cutoff = 14.484).