Association of nutritional–immune indicators and their dynamic changes with disease severity and wound healing in diabetic foot ulcers treated by tibial transverse transport: a retrospective study

Background Although tibial transverse transport (TTT) may promote wound repair in complex diabetic foot ulcer (DFU), reliable indicators reflecting postoperative recovery remain limited. This study aimed to investigate the association of nutritional–immune indicators and their dynamic changes with DFU severity and wound healing time after TTT treatment. Methods This retrospective cohort study included 227 DFU patients who underwent TTT between January 2023 and May 2024. Patients were classified according to Wagner grades. LASSO regression and multivariable logistic regression were used to identify nutritional–immune factors associated with DFU severity, with ROC curve analysis, calibration analysis, and decision curve analysis performed to evaluate model performance. In addition, 147 patients with complete 1-month postoperative laboratory data were analyzed using Cox proportional hazards regression, Kaplan–Meier analysis and time-dependent ROC analysis to evaluate the association between dynamic nutritional–immune changes and subsequent wound healing time. Results Compared with non-severe DFU patients, severe DFU patients showed greater inflammatory activation and nutritional–immune disturbances. Multivariable logistic regression identified ANLR (OR = 0.993, 95% CI: 0.987–0.999, p = 0.020) and PNI (OR = 0.909, 95% CI: 0.853–0.969, p = 0.004) as independently associated with DFU severity. The model incorporating ANLR and PNI showed good discrimination for severe DFU (AUC = 0.825, 95% CI: 0.756–0.893). Baseline PNI and ANLR were not associated with postoperative wound healing time, whereas greater ΔPNI was independently associated with a higher hazard of subsequent wound healing in the severity-stratified Cox model (HR = 1.030, 95% CI: 1.008–1.053, p = 0.008). Kaplan–Meier analysis showed faster wound healing in patients with greater ΔPNI (log-rank p = 0.018). Conclusion PNI and ANLR are associated with DFU severity and may provide complementary information for preoperative risk stratification. An increase in PNI at 1 month after TTT is associated with subsequent wound healing time and may represent an integrated response of nutritional–immune status during the treatment course.