Prognostic performance of the WIfI classification in diabetic patients with infrapopliteal CLTI after endovascular revascularization: a subgroup analysis of the PRIME-WIFI registry

Introduction The Wound, Ischemia, and foot Infection (WIfI) classification is widely used in chronic limb-threatening ischemia (CLTI). However, its prognostic performance in diabetic patients after endovascular revascularization remains unclear. We evaluated its prognostic and discriminatory performance in this population. Methods This subgroup analysis of the prospective, multicenter PRIME-WIFI registry included diabetic patients with infrapopliteal CLTI undergoing endovascular revascularization. Associations between baseline WIfI stage and MAE (all-cause mortality, major amputation, or clinically driven target-limb reintervention), its individual components, amputation-free survival, clinical improvement, and 12-month VascuQoL change were assessed using Kaplan–Meier, multivariable Cox, and Harrell's C-index analyses. Results A total of 707 diabetic patients (730 limbs) were analyzed; in the full PRIME-WIFI cohort, diabetes status showed a borderline interaction with WIfI stage for MAE ( P for interactio n = 0.083). One-year freedom from MAE decreased across WIfI stages (89.5%, 77.4%, 78.0%, and 70.1% for stages 1–4; log-rank P = 0.004), and WIfI stage independently predicted MAE (HR: 1.31; 95% CI: 1.09–1.56; P = 0.0031). One-year AFS was 94.7%, 83.3%, 83.3%, and 74.2% (log-rank P = 0.0003), with higher WIfI stage associated with worse AFS (HR: 1.53; 95% CI: 1.24–1.89; P < 0.001). Overall survival was 94.7%, 87.8%, 86.1%, and 80.3% (log-rank P = 0.009), and WIfI stage was independently associated with mortality (HR: 1.52; 95% CI: 1.20–1.94; P < 0.001). Freedom from major amputation was 100.0%, 95.3%, 96.8%, and 92.3% (log-rank P = 0.02), with higher WIfI stage independently associated with major amputation (HR: 1.62; 95% CI: 1.07–2.57; P = 0.020). In contrast, freedom from CD-TLR did not differ significantly across stages (log-rank P = 0.60; HR: 0.92; 95% CI: 0.68–1.23; P = 0.564). Clinical improvement tended to decrease with increasing WIfI stage but did not reach statistical significance ( P = 0.053). VascuQoL scores improved from baseline to 12 months across all WIfI stages, with no significant difference in the magnitude of improvement among stages (time-by-WIfI interaction P = 0.247). Conclusions In this diabetic subgroup, WIfI retained prognostic value for MAE, AFS, mortality, and major amputation. However, discrimination was clearest between stages 1 and 4, with limited separation between stages 2 and 3. These findings support WIfI for broad risk stratification while highlighting the need for complementary assessment in diabetic CLTI.