Clinical, microbiological and inflammatory markers of severe diabetic foot infections.

AIMS: In addition to systemic inflammatory response syndrome (SIRS), various clinical signs, microbiological findings and inflammatory markers could be associated with severe diabetic foot infections (DFI). METHODS: This study included a retrospective cohort of 245 patients with DFI treated at San Juan de Dios Hospital in San José de Costa Rica. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), CRP/albumin ratio, peripheral blood leucocyte ratios and the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system were evaluated. Univariate analysis was carried out between moderate and severe infections. ROC curves were plotted. Cut-off value of inflammatory markers for diagnosing severe infections was established and then dichotomized to be included in a logistic regression model. A score was designed based on its results. RESULTS: Skin necrosis (p < 0.01, OR = 8.5, 95% CI = 3.5-20.9), ESR > 94 mm/h (p < 0.01, OR = 2.5, 95% CI = 1.2-5.1), albumin < 2.8 g/dl (p = 0.04, OR = 2.0, 95% CI = 1.0-4.1) and neutrophil-to-lymphocyte ratio (NLR) > 4.52 (p < 0.01, OR = 3.3, 95% CI = 1.6-6.5) were found to be predictive of severe infections. Score >5 had a good diagnosis performance for classifying severe infections. Moderate infections with a score >5 had a worse prognosis than moderate ones. CONCLUSIONS: We found an association of necrosis, serum albumin, ESR and NLR values with severe DFI. The presence of these predictive factors of severity in cases of moderate infections was significantly associated with a higher rate of amputations and recurrences, longer duration of antibiotic treatment and longer hospital stays. DFI could be classified as mild, moderate, severe without SIRS and severe.

Conservative Surgery for Diabetic Foot Osteomyelitis is not Associated With Longer Survival Time Without Recurrence of Foot Ulcer When Compared With Amputation.

Conservative surgery of diabetic foot osteomyelitis (DFO) in which bone infection is removed without amputation could minimize the biomechanical changes associated with foot surgery. We hypothesize that patients who undergo conservative surgery will have a longer survival time without recurrence of foot ulcers and further amputations than those who undergo any type of amputation to treat DFO. We assessed a retrospective cohort of 108 patients who underwent surgery for DFO from January 2011 to December 2012. Patients were followed-up until May 2020. Reulceration and reamputation-free survival times were plotted using the Kaplan-Meier method and were calculated from the date of first surgery to recurrence, new amputation, or end of the study. A stratified log rank was used to study differences among groups. Cumulative survival without recurrences at 1, 5, and 8 years was 95%, 36%, and 29%, respectively, in patients who underwent conservative surgery and 95%, 43%, and 30%, respectively, in those undergoing amputation. Cumulative survival without a new amputation at 1, 5, and 8 years was 100%, 80%, and 80%, respectively, in patients who underwent conservative surgery and 98%, 82%, and 69%, respectively, in those undergoing amputation. No differences were found regarding either recurrence (log rank, P = .98) or new amputations (log rank, P = .64). In conclusion, conservative surgery is as safe as amputation to arrest bone infection in the feet of patients with diabetes. Conservative surgery was not associated with a lower rate of recurrence and new amputations than those patients who underwent amputations.

Long-term Mortality of a Cohort of Patients Undergoing Surgical Treatment for Diabetic Foot Infections. An 8-year Follow-up Study.

We analyzed a retrospective cohort of 150 patients with diabetic foot infections (DFIs) who underwent surgical treatment to determine long-term outcomes. The median follow-up of the series was 7.6 years. Cox's proportional hazards model for survival time was performed and hazard ratios (HRs) were estimated. Survival times were plotted using the Kaplan-Meier method. Fifteen patients (10%) required readmission after discharge from the hospital for a recurrence of the infection. Ninety patients (60%) had re-ulcerations. Forty-nine (54.4% of those re-ulcerated) required new admission and 24 of them (26.6% of those re-ulcerated) finally required a new amputation. Overall cumulative survival rates at 1, 5, and 8 years were 95%, 78%, and 64%, respectively. Predictive variables of long-term mortality were insulin treatment (HR: 2.0, 95% CI: 1.1-3.6, P = .01), female sex (HR: 3.1, 95% CI: 1.7-5.3, P<.01) and estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 (HR: 2.2, 95% CI: 1.1-4.2, P = .01). In conclusion, patients undergoing surgical treatment for DFIs had a high rate of recurrences and mortality. Women, patients who underwent treatment with insulin, and those with eGFR <60 ml/min/1.73 m2 had a higher risk of long-term mortality.

Does Metabolic Control Have Any Influence on the Clinical Presentation and Short-Term Outcomes of Diabetic Foot Infections?

Objective: We hypothesized that patients with poor glycemic control undergoing treatment for diabetic foot infections (DFIs) would have a poorer prognosis than those with better metabolic control assessed by glycated hemoglobin (HbA1c). Approach: We analyzed a retrospective cohort of 245 patients with moderate and severe DFIs. HbA1c values were dichotomized (<7% or ≥7% and ≤75th percentile (P75) and >P75) to analyze patient outcomes regarding metabolic control. The present study adhered to the STROBE guidelines for cohort studies. Results: One hundred sixty-nine patients (69%) were men. Their mean age was 60.7 years (10.8). HbA1c ≥7% was detected in 203 patients (82.9%). P75 HbA1c was 10.9%. After performing univariate analysis, we found an association of HbA1c <7% with major amputations and mortality. However, after applying the logistic regression model, we did not find HbA1c <7% to be a predictive factor of major amputation. The risk factors for mortality following application of Cox's proportional hazards model were osteomyelitis (HR: 0.2, 95% CI: 0.07-0.62, p < 0.01), eGFR <60 mL/min/1.73 m2 (HR: 2.7, 95% CI: 1.0-7.5, p = 0.04), and HbA1c <7% (HR: 4.9, 95% CI: 1.8-13.2, p < 0.01). Innovation: The group with optimal glycemic control (HbA1c <7%) had a shorter survival time than those with worse metabolic control. Conclusions: We did not find a longer duration of hospitalization, a higher rate of amputations, or longer healing times in the groups with worse metabolic control. HbA1c <7% was a risk factor for mid-term mortality.

Surgical Diabetic Foot Infections: Is Osteomyelitis Associated With a Worse Prognosis?

It has been reported that patients with diabetes and foot ulcers complicated with osteomyelitis (OM) have a worse prognosis than those complicated with soft tissue infections (STI). Our study aimed to determine whether OM is associated with a worse prognosis in cases of moderate and severe diabetic foot infections requiring surgery. A retrospective series consisted of 150 patients who underwent surgery for diabetic foot infections. We studied the differences between OM versus STI. Furthermore, diabetic foot infections were reclassified into four groups: moderate STI (M-STI), moderate OM (M-OM), severe STI (S-STI), and severe OM (S-OM). The variables associated with prognosis were limb loss, length of hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing (both the initial ulcer and the postoperative wound). No differences in limb salvage, hospital stay, duration of antibiotic treatment, recurrence of the infection, and time to healing were found when comparing OM with STI. Patients with M-O had a higher rate of recurrences after initial treatment and a longer time to healing when comparing with M-STI. We didn't find any differences between severe infections with or without OM. In conclusion, we have found in our surgical series of diabetic foot infections that OM is not associated with worse prognosis when comparing with STI regarding limb loss rate, length of hospital stays, duration of antibiotic treatment, recurrence of the infection, and time to healing. The results of the present series should further be confirmed by other authors.

Virulence Factor Genes in Staphylococcus aureus Isolated From Diabetic Foot Soft Tissue and Bone Infections.

The aim of this study is to describe the presence of genes encoding for 4 virulence factors (pvl, eta, etb, and tsst), as well as the mecA gene conferring resistance to beta-lactam antibiotics, in patients with diabetes and a staphylococcal foot infection. We have also analyzed whether isolates of Staphylococcus aureus from bone infections have a different profile for these genes compared with those from exclusively soft tissue infections. In this cross-sectional study of a prospectively recruited series of patients admitted to the Diabetic Foot Unit, San Juan de Dios Hospital, San José, Costa Rica with a moderate or severe diabetic foot infection (DFI), we collected samples from infected soft tissue and from bone during debridement. During the study period (June 1, 2014 to May 31, 2016), we treated 379 patients for a DFI. S aureus was isolated from 101 wound samples, of which 43 were polymicrobial infections; we only included the 58 infections that were monomicrobial S aureus for this study. Infections were exclusively soft tissue in 17 patients (29.3%) while 41 (70.7%) had bone involvement (osteomyelitis). The mecA gene was detected in 35 cases (60.3%), pvl gene in 4 cases (6.9%), and tsst gene in 3 (5.2%). We did not detect etA and etB in any of the cases. There were no differences in the profile of S aureus genes encoding for virulence factors (pvl, etA, etB, and tsst) recovered from DFIs between those with just soft tissue compared to those with osteomyelitis. However, we found a significantly higher prevalence of pvl+ strains of S aureus associated with soft tissue compared with bone infections. Furthermore, we observed a significantly longer time to healing among patients infected with mecA+ (methicillin-resistant) S aureus (MRSA).