The Infected Diabetic Foot: Re-Evaluating the IDSA Diabetic Foot Infection Classification.

Abstract

BACKGROUND\nOur goal is to provide evidence to revise the IDSA diabetic foot infection classification. We propose adding a separate tier for osteomyelitis and evaluating if moderate and severe infection criteria improves the classification s ability to direct therapy and determine outcomes.\n\n\nMETHODS\nWe included 294 patients in this retrospective cohort study of moderate and severe diabetic foot infections. Diabetic foot osteomyelitis was confirmed by bone culture or histopathology. Soft tissue infection (STI) was based on negative bone culture, MRI, or SPECT CT. We stratified STI and osteomyelitis based on the IDSA criteria for moderate and severe infections and compared outcomes and post discharge complications.\n\n\nRESULTS\nOsteomyelitis patients had worse outcomes than STI: antibiotic duration (32.5±46.8 vs 63.8±55.1 days, p<0.01), need for surgery (55.5% vs 99.4%, p<0.01), number of surgeries (2.1±1.3 vs 3.3±2.3, p<0.01), amputation (26.3% vs 83.4%, p<0.01), re-infection (38.0% vs 56.7%, p<0.01), acute kidney injury (AKI) (37.2% vs 49.7%, p=0.04), and length of stay (14.5±14.9 vs 22.6±19.0 days, p<0.01). There were no differences in moderate and severe STI outcomes except for infection re-admissions (46.2% vs 25.0%, p=0.02), and AKI (31.2% vs 50.0%, p=0.03). There were no differences in moderate and severe osteomyelitis except the number of surgeries (2.8±2.1 vs 4.1±2.5, p<0.01), and length of stay (18.6±17.5 vs 28.2±17.7, p<0.01).\n\n\nCONCLUSIONS\nThe IDSA diabetic foot infection classification better reflects outcomes, opposed to current criteria, if risk categories were stratified by infection type (STI or osteomyelitis) and moderate and severe infections are not categorized separately.