Objective To investigate the prognostic significance of the neutrophil-to-platelet ratio （NPR） in combination with C-reactive protein （CRP） in patients with lower extremity arteriosclerosis obliterans （ASO）. Methods A retrospective analysis was conducted on the clinical data of 209 patients with lower extremity ASO admitted to the Department of Critical Care Medicine at Zhongshan Hospital Affiliated to Fudan University （Xiamen） between January 2020 and February 2024. Patients were categorized into either the survival group or the death group based on their in-hospital prognosis. The NPR was calculated on the day of ICU admission， as was the level of CRP. Differences in NPR， CRP， and the combination of NPR and CRP between the two groups were then compared. The prognostic value of NPR， CRP， and their combined use for predicting outcomes in patients with lower extremity ASO was evaluated using receiver operating characteristic （ROC） curve analysis. Based on the optimal cutoff value derived from the ROC curve for the combination of NPR and CRP， patients were divided into two groups. Kaplan-Meier survival analysis was subsequently performed to assess differences in survival outcomes between these two groups. Results The levels of NPR， CRP， alanine aminotransferase， aspartate aminotransferase， creatinine， B-type natriuretic peptide， troponin， and procalcitonin， as well as the proportion of patients with kidney disease in the survival group， were significantly lower than those in the death group， and the differences were statistically significant （P < 0.05）. The albumin level in the survival group was significantly higher than that in the death group， with a statistically significant difference （P < 0.05）. Binary logistic regression analysis revealed that NPR， CRP， the combination of NPR and CRP， and the presence of comorbid kidney disease were independent risk factors influencing patient survival prognosis. ROC curve analysis showed that the areas under the curve （AUC） for NPR， CRP， and the combination of NPR and CRP were 0.648， 0.812， and 0.828， respectively. Both CRP and the combination of NPR and CRP demonstrated statistically significant （P < 0.05）. Compared with either NPR or CRP alone， their combined use showed improved predictive performance. Based on the ROC curve for the combination of NPR and CRP， the optimal cutoff value was determined as 0.029 using the maximum Youden Index. Patients were then divided into high and low NPR + CRP groups according to this cutoff. Kaplan-Meier survival analysis revealed that the in-hospital survival rate in the low NPR + CRP group was significantly higher than that in the high NPR + CRP group， and the difference in survival between the two groups was statistically significant （P = 0.001）. Conclusion NPR combined with CRP is associated with the prognosis of patients with lower extremity ASO and may serve as an effective predictive indicator for their clinical outcomes.