Prediction of diabetic foot amputation using newly revised DIRECT coding system: Comparison of accuracy with that of five existing classification systems

SLR - September 2022 - Kara Goettl PGY-1

Reference: Lee DW, Kwak SH, Kim JH, Choi HJ. Prediction of diabetic foot amputation using newly revised DIRECT coding system: Comparison of accuracy with that of five existing classification systems. Int Wound J. 2022 Jul 10. doi: 10.1111/iwj.13884. Epub ahead of print. PMID: 35811359.

Level of Evidence: Level 3

Scientific Literature Review

Reviewed By: Kara Goettl PGY-1
Residency Program: The Jewish Hospital-Mercy Health, Cincinnati, OH

Podiatric Relevance: The study sought to compare the DIRECT3 coding system with existing classification systems and to determine significant risk factors in predicting LE amputation

Methods: Authors retrospectively review patient records over 5 years with diabetic foot ulcerations. 131 patients were included in the study after exclusion criteria. Variables pertinent to the patients past medical history were applied to 5 wound classification systems including: DUSS, UT, Wagner, DEPA, SINBAD as well as the new DIRECT coding system.  

Results:
  • Of 131 recruited patients, 66 healed and 65 underwent lower extremity amputation. 
  • Accuracy of these classification systems was examined by calculating sensitivity, specificity, classification accuracy, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC).
  • The DIRECT3 coding system with additional variables such as CRP, UH, and HTN, had the highest sensitivity and NPV values which had the best predictive power among the existing classification system
Conclusions:
  • The DIRECT system increased the objectivity by adding laboratory and clinical data such as CRP, UH, and HTN , which is the highest predictive value in DIRECT 3 and it has been proven as a result with accuracy.
  • The DIRECT coding system has user-friendly design, which provides an understanding of the condition of the wound and suggests the most practical treatment for wound care providers.
  • The DIRECT system stressed the importance of revascularization category(R), a category not found in other classifications. 
  • The DIRECT3 coding system with additional variables such as CRP, UH, and HTN, had the highest sensitivity and NPV values which had the best predictive power among the existing classification systems
  • Duration of diabetes and HTN, levels of Hb and CRP, and UH were noted as significant risk factors for predicting lower extremity amputation.
  • Through the DIRECT system, it can be suggested that
  • DFU can be properly treated at an early stage, and progression to LEA can be prevented through proper infection control and revascularization.
  • This classification system would be beneficial in the future as an all-encompassing tool that would assess risk and direct treatment to prevent amputation. This would allow for quick assessment of both hospital patients and clinical patients in determining the level of monitoring required for their specific wounds. Having a tool to decrease the potential of limb loss if a great advancement in the field of podiatric medicine.