Prevalence of infection in amputations in patients with diabetic foot ulcer: a retrospective study

To investigate the prevalence of infection in diabetic foot ulcers (DFUs) and its association with lower limb major and minor amputations, examining demographic and socioeconomic factors influencing DFU outcomes.

This retrospective study analyzed data from the Indiana Network for Patient Care (INPC) from January 2019 to May 2024. A total of 27,078 patients with DFUs were included, aged 9 to 103 years. Data included demographics, clinical encounters, ICD-10, CPT codes, laboratory values, and microbiological assessments. Analyses included Pearson correlation, logistic regression, and one-sample proportion tests.

Patients were predominately male (64.3%) and female (35.7%) with a mean age of 63.8 years. DFU prevalence showed significant inverse correlation with median income (r=0.2108, p=0.0016); lower-income areas (median income < $64,200) had DFU rates > 5.0 per 1,000 population. Of cultured specimens, 33.79% showed infections, primarily Staphylococcus spp. (22.52%) and Streptococcus spp. (11.27%). In major and minor amputation cases with microbial data available, Staphylococcus spp. (22.75%), Enterococcus spp. (11.86%) and Streptococcus spp. (10.42%) genera were most common. Osteomyelitis increased amputation odds by 7.83 times (p<0.001).

Bacterial infections, particularly Staphylococcus, Enterococcus and Streptococcus genera were strongly associated with amputation risk. These findings have important clinical implications: early identification of these specific bacterial pathogens could guide targeted antibiotic therapy and inform risk stratification for amputation prevention. Improved bacterial identification could enhance DFU management and reduce complications such as amputation.