Biomarker Prediction of Postoperative Healing of Diabetic Foot Ulcers: A Retrospective Observational Study of Serum Albumin

Risk factors and a predictive model of diabetic foot in hospitalized patients with type 2 diabetes

BACKGROUND

The risk factors and prediction models for diabetic foot (DF) remain incompletely understood, with several potential factors still requiring in-depth investigations.

AIM

To identify risk factors for new-onset DF and develop a robust prediction model for hospitalized patients with type 2 diabetes.

METHODS

We included 6301 hospitalized patients with type 2 diabetes from January 2016 to December 2021. A univariate Cox model and least absolute shrinkage and selection operator analyses were applied to select the appropriate predictors. Nonlinear associations between continuous variables and the risk of DF were explored using restricted cubic spline functions. The Cox model was further employed to evaluate the impact of risk factors on DF. The area under the curve (AUC) was measured to evaluate the accuracy of the prediction model.

RESULTS

Seventy-five diabetic inpatients experienced DF. The incidence density of DF was 4.5/1000 person-years. A long duration of diabetes, lower extremity arterial disease, lower serum albumin, fasting plasma glucose (FPG), and diabetic nephropathy were independently associated with DF. Among these risk factors, the serum albumin concentration was inversely associated with DF, with a hazard ratio (HR) and 95% confidence interval (CI) of 0.91 (0.88-0.95) (P < 0.001). Additionally, a U-shaped nonlinear relationship was observed between the FPG level and DF. After adjusting for other variables, the HRs and 95%CI for FPG < 4.4 mmol/L and ≥ 7.0 mmol/L were 3.99 (1.55-10.25) (P = 0.004) and 3.12 (1.66-5.87) (P < 0.001), respectively, which was greater than the mid-range level (4.4-6.9 mmol/L). The AUC for predicting DF over 3 years was 0.797.

CONCLUSION

FPG demonstrated a U-shaped relationship with DF. Serum albumin levels were negatively associated with DF. The prediction nomogram model of DF showed good discrimination ability using diabetes duration, lower extremity arterial disease, serum albumin, FPG, and diabetic nephropathy (Clinicaltrial.gov NCT05519163).

The Risk of and Associated Demographic and Laboratory Variables for Amputations for Inpatients with Diabetic Foot Ulcers

OBJECTIVE

Diabetic foot ulcers (DFUs) are a leading cause of morbidity and mortality, which disproportionately impacts underserved populations. This study aimed to provide data regarding the rates and outcomes of amputation in patients admitted with DFU in our health system, which cares for an ethnically diverse and underserved population.

METHODS

This retrospective study examined the electronic medical records of adult patients hospitalized with DFU at 3 hospitals in our health system between June 1, 2016, and May 31, 2021.

RESULTS

Among 650 patients admitted with DFU, 88% self-identified as non-White race. Male sex (odds ratio [OR], 0.62), low body mass index (OR, 0.98), and history of smoking (OR, 1.45) were significantly associated with amputation during the study period. A higher erythrocyte sedimentation rate (OR, 1.01), C-reactive protein level (OR, 1.05), and white blood cell count (OR, 1.11) and low albumin level (OR, 0.41) were found to be significantly associated with amputation versus no amputation during admission. The amputation risk during the index admission for DFU was 44%.

CONCLUSION

Our study identified a high DFU-related amputation risk (44%) among adult patients who were mostly Black and/or Hispanic. The significant risk factors associated with DFU amputation included male sex, low body mass index, smoking, and high levels inflammation or low levels of albumin during admission. Many of these patients required multidisciplinary care and intravenous antibiotic therapy, necessitating a longer length of stay and high readmission rate.

Factors Influencing Wound Healing in Diabetic Foot Patients

Background and objectives: Diabetic foot stands out as one of the most consequential and devastating complications of diabetes. Many factors, including VIPS (Vascular management, Infection management, Pressure relief, and Source of healing), influence the prognosis and treatment of diabetic foot patients. There are many studies on VIPS, but relatively few studies on "sources of healing". Nutrients that affect wound healing are known, but objective data in diabetic foot patients are insufficient. We hypothesized that "sources of healing" would have many effects on wound healing. The purpose of this study is to know the affecting factors related to the source of healing for diabetic foot patients. Materials and Methods: A retrospective review identified 46 consecutive patients who were admitted for diabetic foot management from July 2019 to April 2021 at our department. Several laboratory tests were performed for influencing factor evaluation. We checked serum levels of total protein, albumin, vitamin B, iron, zinc, magnesium, copper, Hb, HbA1c, HDL cholesterol, and LDL cholesterol. These values of diabetic foot patients were compared with normal values. Patients were divided into two groups based on wound healing rate, age, length of hospital stay, and sex, and the test values between the groups were compared. Results: Levels of albumin (37%) and Hb (89%) were low in the diabetic foot patients. As for trace elements, levels of iron (97%) and zinc (95%) were low in the patients, but levels of magnesium and copper were usually normal or high. There were no differences in demographic characteristics based on wound healing rate. However, when compared to normal adult values, diabetic foot patients in our data exhibited significantly lower levels of hemoglobin, total protein, albumin, iron, zinc, copper, and HDL cholesterol. When compared based on age and length of hospital stay, hemoglobin levels were significantly lower in both the older age group and the group with longer hospital stays. Conclusions: Serum levels of albumin, Hb, iron, and zinc were very low in most diabetic foot patients. These low values may have a negative relationship with wound healing. Nutrient replacements are necessary for wound healing in diabetic foot patients.

Surgical Optimization for Charcot Patients

Reconstruction of the Charcot foot and ankle demonstrates significant challenges to the foot and ankle surgeon. At present, there is limited clear consensus on the best approach for preoperative optimization. The primary aim of Charcot reconstructions is to limit the risk of ulceration by providing a stable plantigrade foot allowing ambulation. The focus of this article is the discussion of modifiable risk factors associated with Charcot reconstruction for preoperative optimization.

Circulating Biomarkers of Endothelial Dysfunction and Inflammation in Predicting Clinical Outcomes in Diabetic Patients with Critical Limb Ischemia

Critical limb ischemia (CLI) is a severe manifestation of peripheral artery disease characterized by ischemic pain, which is frequently associated with diabetes and non-healing lesions to inferior limbs. The clinical management of diabetic patients with CLI typically includes percutaneous transluminal angioplasty (PTA) to restore limb circulation and surgical treatment of diabetic foot ulcers (DFU). However, even after successful treatment, CLI patients are prone to post-procedure complications, which may lead to unplanned revascularization or foot surgery. Unfortunately, the factors predicting adverse events in treated CLI patients are only partially known. This study aimed to identify potential biomarkers that predict the disease course in diabetic patients with CLI. For this purpose, we measured the circulating levels of a panel of 23 molecules related to inflammation, endothelial dysfunction, platelet activation, and thrombophilia in 92 patients with CLI and DFU requiring PTA and foot surgery. We investigated whether these putative biomarkers were associated with the following clinical endpoints: (1) healing of the treated DFUs; (2) need for new revascularization of the limb; (3) appearance of new lesions or relapses after successful healing. We found that sICAM-1 and endothelin-1 are inversely associated with DFU healing and that PAI-1 and endothelin-1 are associated with the need for new revascularization. Moreover, we found that the levels of thrombomodulin and sCD40L are associated with new lesions or recurrence, and we show that the levels of these biomarkers could be used in a decision tree to assign patients to clusters with different risks of developing new lesions or recurrences.

Diabetic Wound-Healing Science

Diabetes mellitus is an increasingly prevalent chronic metabolic disease characterized by prolonged hyperglycemia that leads to long-term health consequences. It is estimated that impaired healing of diabetic wounds affects approximately 25% of all patients with diabetes mellitus, often resulting in lower limb amputation, with subsequent high economic and psychosocial costs. The hyperglycemic environment promotes the formation of biofilms and makes diabetic wounds difficult to treat. In this review, we present updates regarding recent advances in our understanding of the pathophysiology of diabetic wounds focusing on impaired angiogenesis, neuropathy, sub-optimal chronic inflammatory response, barrier disruption, and subsequent polymicrobial infection, followed by current and future treatment strategies designed to tackle the various pathologies associated with diabetic wounds. Given the alarming increase in the prevalence of diabetes, and subsequently diabetic wounds, it is imperative that future treatment strategies target multiple causes of impaired healing in diabetic wounds.