Diabetic foot ulcers (DFUs) are a severe complication of diabetes, representing a leading cause of hospitalization among diabetic patients. The prevalence of DFUs is substantial, affecting up to 25% of individuals with diabetes during their lifetime. Malnutrition, defined as a state of reduced body composition and body cell mass impacting physical and mental functioning, significantly exacerbates the challenges associated with DFUs. Long-term hyperglycemia, coupled with increased energy expenditure for wound healing in DFU patients, contributes to nutritional imbalances. Malnutrition in DFU patients slows wound healing, increases recurrence risk, and raises medical burden, negatively impacting quality of life. Studies show widely varying malnutrition prevalence in DFU patients (15-62%), owing to different diagnostic methods and patient populations. Malnutrition is also a strong predictor of poor outcomes, including amputation. While factors like BMI, Wagner grade, and ulcer infection have been implicated as risk factors, inconsistencies exist across studies. The Global Leadership Initiative on Malnutrition (GLIM) criteria, published in 2019, provide a standardized approach to malnutrition diagnosis. This study aimed to determine the incidence and risk factors of malnutrition in DFU patients using the GLIM criteria, and to investigate the association between nutritional status and length of hospital stay (LOS).

Previous research has explored the prevalence and risk factors of malnutrition in DFU patients, reporting widely varying rates (15-62%) depending on the diagnostic methods and study populations. Studies have identified BMI, Wagner grade, and ulcer infection as potential risk factors, but inconsistencies remain. Only one study had previously utilized the GLIM criteria for malnutrition assessment in DFU patients. This lack of consistency in methodology and limited use of the GLIM criteria underscored the need for a more comprehensive investigation using a standardized approach.

This observational cohort study included 219 consecutively hospitalized DFU patients from two campuses of a hospital in Chongqing, China, between January 2021 and June 2023. Inclusion criteria included a DFU diagnosis according to the International Working Group on Diabetic Foot guidelines, age ≥18 years, consent obtained, diabetes duration >1 year, and blood glucose management medication. Exclusion criteria included severe physical or mental diseases hindering assessment, previous amputation or revascularization, tuberculosis, hyperthyroidism, malignant tumors, or gastrointestinal disease/surgery. Sample size calculation using G*Power 3.1 software determined a minimum sample size of 164 patients. The study was approved by the Ethics Committee of the Second Hospital of Chongqing Medical University (NO: 2022.30). Data collection involved questionnaires and electronic medical records, gathering information on demographics, BMI, medical history (smoking, alcohol, hypertension, dyslipidemia), diabetes and DFU duration, treatment modality, ulcer infection, diabetes-related complications, SINBAD score, and ABI. Lower extremity assessments were conducted by qualified diabetologists or certified nurses. Diabetic peripheral neuropathy (DPN) and diabetic nephropathy (DN) were diagnosed according to established guidelines. Laboratory measurements (Hb, HbA1c, CRP, eGFR, Alb) were performed. Nutritional assessment within 24 hours of admission involved NRS-2002 screening and GLIM criteria application. Statistical analysis included descriptive statistics, Student's t-test, Mann-Whitney U test, chi-square test, and multivariate binary logistic regression analysis (Forward LR method) to identify risk factors for malnutrition and assess the relationship between malnutrition and prolonged LOS (defined as >17 days).

After excluding 25 participants, 219 DFU patients (mean age 67 ± 12 years) were included. Malnutrition, defined by GLIM criteria, was present in 84 patients (38.36%). The median LOS was 16 days (IQR, 15-20 days), with 92 patients (42%) exhibiting prolonged LOS. Univariate analysis showed potential associations between malnutrition and BMI, dyslipidemia, ulcer infection, DPN, DN, SINBAD score, ABI, CRP, Hb, Alb, HbA1c, and LOS. Multivariate logistic regression analysis identified BMI (P<0.001), Alb (P=0.002), HbA1c (P<0.001), ulcer infection (P<0.001), LOS (P=0.010), and ABI (P=0.024) as independent risk factors for malnutrition. The model explained 71.6% of the variability (Hosmer-Lemeshow test: χ²=3.115, P=0.927). Analysis of prolonged LOS revealed significant associations with DPN (P=0.033), DN (P<0.001), and malnutrition (P=0.001). Malnourished patients were 2.857 times more likely to have prolonged LOS (95% CI, 1.497-5.450; P=0.001). The model for prolonged LOS explained 29.5% of the variability (Hosmer-Lemeshow test: χ²=2.344, P=0.310).

This study is the first to demonstrate a strong association between GLIM-defined malnutrition and prolonged LOS in DFU patients. The high prevalence of malnutrition (38.36%) underscores the need for routine nutritional screening and assessment in DFU patients. The findings align with previous research demonstrating the negative impacts of low BMI, ulcer infection, and high HbA1c on DFU outcomes. The association of low serum albumin with malnutrition reflects its crucial role in maintaining plasma colloid osmotic pressure and nutrient absorption. Reduced ABI indicates impaired vascular function, potentially impacting nutrient delivery to the ulcer site. The study's finding that malnutrition is associated with a nearly threefold increase in the likelihood of prolonged LOS emphasizes the importance of early nutritional intervention in improving patient outcomes and reducing healthcare costs. However, the study's findings contradict a previous study by Lauwers et al., showing no significant difference in short-term outcomes between well-nourished and malnourished DFU patients. This discrepancy may be due to differences in sample size and exclusion criteria.

This study highlights the high prevalence of malnutrition (38.36%) in DFU patients using GLIM criteria and identifies BMI, Alb, HbA1c, ulcer infection, LOS, and ABI as key risk factors. Malnutrition was strongly associated with prolonged LOS. These findings emphasize the need for routine nutritional screening, assessment, and timely intervention in DFU patients to improve outcomes and reduce hospital stays. Future research should explore the impact of different nutritional interventions on LOS and long-term outcomes in DFU patients and investigate the use of GLIM criteria to grade malnutrition severity for better prognostication.

Several limitations exist. Nutritional assessment was performed only at admission, lacking data on changes in nutritional status during and after hospitalization. Data on weight loss relied on patient recall, and other comorbidities not explicitly mentioned might influence results. The study's findings should be interpreted cautiously, with larger studies warranted for validation. Furthermore, the study did not assess the degree of malnutrition (moderate vs. severe), which may affect the correlation with prognosis.