Prognostic Value of Wagner Grade and Platelet Level in Diabetics with Infected Foot Ulcers After Antibiotic Therapy

The aim of the current study was to investigate factors potentially associated with the healing of infected foot ulcers in patients with diabetes after antimicrobial therapy with drugs selected based on antimicrobial susceptibility testing.

A retrospective study was conducted to analyze clinical data from 99 type 2 diabetes mellitus patients with foot infection admitted to our center from January 2016 to December 2020. Pathogenic characteristics, results of wound discharge testing, and relevant wound surface factors were analyzed. Etiological characteristics and the results of susceptibility testing, wound healing rates, and factors potentially associated with wound healing rates were also analyzed.

Baseline data were analyzed via the t-test for independent samples, the Mann-Whitney U-test, and the chi-square test to identify variables significantly associated with prognosis. Least absolute shrinkage and selection operator regression analysis then determined that Wagner grade, essential hypertension, platelets, Gram negative bacteria, and neutrophil-to-lymphocyte ratio were of predictive value. A nomogram plot was built based on these five variables, and it yielded a standard C-index of 0.964, and an internally corrected C-index of 0.931. In multivariate logistic regression analysis Wagner grade (odds ratio [OR] 12.30, 95% confidence interval [CI] 2.471-61.194, p = 0.002) and platelet level (OR 0.978, 95% CI 0.960-0.996, p = 0.018) were significantly associated with wound healing outcomes. Restricted cubic spline analysis indicated that there was a linear relationship between wound healing and platelet levels, and that this relationship was strongest in patients classified as Wagner grade 2 with a platelet count ≤ 200 (p for nonlinearity = 0.442).

Wagner grade, essential hypertension, platelet count, Gram negative bacteria, and neutrophil-to-lymphocyte ratio could predict the course of healing of infected foot ulcers in type 2 diabetes mellitus patients. When the Wagner grade was 2 and the platelet level was ≤ 200, platelet level was linearly associated with healing outcome, whereby a lower platelet level predicted a worse wound healing outcome.