Diabetic foot infections (DFIs) are the most common cause of hospitalization for patients with diabetes. Studies have shown diabetic patients have high readmission rates. It is important to identify variables that contribute to readmission. This study aimed to investigate clinical variables associated with 30-day hospital readmission in patients with DFI.
We conducted a retrospective study of adults admitted to the hospital for DFI between July 1, 2012, and July 1, 2015. We identified patients by International Classification of Diseases, Ninth Revision codes and randomly selected 35% of medical records for review. Patients were excluded if they did not have a DFI by review, were pregnant, or were incarcerated. The primary outcome was 30-day readmission. Data collected included baseline demographics, medical comorbidities, substance abuse, homelessness, tobacco use, and laboratory and surgical pathology data. Univariate and multivariate logistic regression models were used to identify independent predictors.
Of 140 included patients, 106 (76%) were male. Median age was 55 years and length of stay (LOS) was 7 days. In univariate analysis, 31 patients (22%) were readmitted in the 30 days after the index hospitalization. Factors associated with readmission included treatment failure, elevated C-reactive protein level, and hospital LOS (P < .05). In multivariate analyses, LOS and treatment failure were independent predictors of readmission.
The 30-day readmission rate for patients with DFI is high. Treatment failure, C-reactive protein, and LOS are independently associated with readmission. More work is needed to determine reasons for readmission so that appropriate measures can be taken before discharge.
Below-the-knee amputation (BKA) can be a detrimental outcome of diabetic foot osteomyelitis (DFO). Ideal treatment of DFO is controversial, but studies suggest minor amputation reduces the risk of BKA. We evaluated risk factors for BKA after minor amputation for DFO.
This is a retrospective cohort of patients discharged from Denver Health Medical Center from February 1, 2012, through December 31, 2014. Patients who underwent minor amputation for diagnosis of DFO were eligible for inclusion. The outcome evaluated was BKA in the 6 months after minor amputation.
Of 153 episodes with DFO that met the study criteria, 11 (7%) had BKA. Failure to heal surgical incision at 3 months (P < .001) and transmetatarsal amputation (P = .009) were associated with BKA in the 6 months after minor amputation. Peripheral vascular disease was associated with failure to heal but not with BKA (P = .009). Severe infection, bacteremia, hemoglobin A1c, and positive histopathologic margins of bone and soft tissue were not associated with BKA. The median antibiotic duration was 42 days for positive histopathologic bone resection margin (interquartile range, 32–47 days) and 16 days for negative margin (interquartile range, 8–29 days). Longer duration of antibiotics was not associated with lower risk of BKA.
Patients who fail to heal amputation sites in 3 months or who have transmetatarsal amputation are at increased risk for BKA. Future studies should evaluate the impact of aggressive wound care or whether failure to heal is a marker of another variable.
Pseudomonas aeruginosa has traditionally been considered a common pathogen in diabetic foot infection (DFI), yet the 2012 Infectious Diseases Society of America guideline for DFI states that “empiric therapy directed at P aeruginosa is usually unnecessary.” The objective of this study was to evaluate the frequency of P aeruginosa isolated from bone or tissue cultures from patients with DFI.
This study is a cross-sectional survey of diabetic patients presenting with a foot infection to an urban county hospital between July 1, 2012, and December 31, 2013. All of the patients had at least one debridement procedure during which tissue or bone cultures from operative or bedside debridements were obtained. The χ2 test and the t test of means were used to determine relationships between variables and the frequency of P aeruginosa in culture.
The median number of bacteria isolated from DFI was two. Streptococcus spp and Staphylococcus aureus were the most commonly isolated organisms; P aeruginosa was isolated in only five of 112 patients (4.5%). The presence of P aeruginosa was not associated with the patient's age, glycosylated hemoglobin level, tobacco abuse, the presence of osteomyelitis, a prescription for antibiotic drugs in the preceding 3 months, or the type of operative procedure.
Pseudomonas aeruginosa was an infrequent isolate from DFI in this urban, underserved diabetic population. The presence of P aeruginosa was not associated with any measured risk factors. By introducing a clinical practice guideline, we hope to discourage frontline providers from using routine antipseudomonal antibiotic drugs for DFI.