From Ulcer to Amputation: A Systematic Review of Prognostic Models for Diabetic Foot Ulcer Amputation

Abstract

Aim: To systematically analyze and compare studies on risk prediction models for diabetic foot ulcers progressing to amputation, facilitate clinical decision-making, and provide recommendations for improving modeling strategies in future research. Methods: We searched Medline, Embase, Cochrane Library, and Clinicaltrials.gov from inception to January 29, 2025, to identify studies on risk prediction models for diabetic foot ulcers progressing to amputation. After study screening and data extraction, we evaluated bias and applicability using the Prediction Model Risk of Bias Assessment Tool. Results: We included 18 papers comprising 15 development studies and 3 external validation studies. The development studies reported 17 models, while the validation studies externally validated 12 models. The area under the curve of all models ranged from 0.557 to 0.957. The most commonly used predictors were peripheral arterial disease, glycated hemoglobin, infection, Wagner classification, and ulcer depth. All included studies had low concerns regarding applicability but exhibited high risk of bias, primarily due to insufficient events per variable, missing data, inadequate consideration of data complexity, lack of model performance assessment, and absence of internal validation. Conclusion: Risk prediction model research for diabetic foot ulcer progression to amputation remains in its early stages. Future efforts should prioritize prospectively developing and externally validating models with robust performance and low bias, accompanied by rigorous internal validation and transparent reporting. (Funding: Natural Science Foundation of Hubei Province (2022CFB145) and Research Fund of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (2023D36)).