Association between blood urea nitrogen concentration and diabetic foot ulcer: A retrospective cross-sectional study based on NHANES

This study explores the relationship between blood urea nitrogen (BUN) levels and diabetic foot ulcer (DFU) in patients over the age of 40 in the United States. A total of 1673 participants who took part in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004 were included in this study. Four logistic regression models were developed to assess the relationship between BUN levels and DFU. Smoothed curve-fitting analysis and threshold effect analysis were used to further specify the type of association. Subsequently, subgroup analyses were performed using stratified multiple regression analysis with age, sex, body mass index (BMI), and HbA1C. The study included 1622 adults with a mean age of 64.60 ± 11.82 years, of which 53.08% were male. Of the participants, 131 (8.07%) had DFU. In a multivariate logistic regression model, the highest BUN level was strongly associated with an increased risk of DFU (OR = 3.56, 95% CI: 1.47-8.62; P = .007). Smooth curve-fitting analysis showed a linear correlation between BUN and DFU (P for nonlinear = .056), with a threshold point of BUN = 5.4 mmol/L. These results suggest a possible linear positive correlation between BUN levels and DFU. Regular monitoring of BUN levels in diabetic patients can be helpful for early diagnosis and intervention of DFU.