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

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

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

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.

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.

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).