The association of serum uric acid with severity and prognosis of patients with diabetic foot ulcers

Background: Diabetic foot ulcers (DFU) as one of the most severe complications of diabetes was characterized by high mortality and incidence of cardiovascular events. Serum uric acid (UA) was well known for cause of gout which was closely related with cardiovascular complications, but also known as the main antioxidant in extracellular fluid. In this study, we aimed to investigate whether serum UA was related with severity and prognosis of patients with DFU. Design and methods: 535 patients with diabetes and firstly diagnosed with DFU hospitalized in Ruijin hospital was consecutively recruited. Concentration of serum UA was examined when admission. Participants were grouped into three groups according to tertiles of their serum UA level. These patients were followed up for an average of 48 months to observe the outcomes, including wound healing, non-fatal cerebral and cardiovascular events (NCCE) and all-cause death. The association of serum UA concentration with the severity of disease evaluated through Wagner and Infection degree, and risk of outcomes were analyzed through partial correlation and Cox regression analysis, respectively. Results: In bivariate correlation analysis, UA was negatively correlated with the Wagner (r=-0.159, P <0.001) and Infection degree (r=-0.171, P <0.001). In partial correlation, UA was still negatively and independently correlated with the Wagner (r=-0.74, P <0.001) and Infection degree (r=-0.190, P <0.001) after controlling for age, sex, type of diabetes, duration of diabetes, duration of DFU, PAD, HbA1c, serum creatine and urine protein excretion in 24hours. In terms of Cox regression analysis, UA was positively and independently related with the risk of NCCE (HR = 1.002, 1.000 to 1.004, P = 0.011), all-cause mortality (HR = 1.003, 1.001 to 1.004, P = 0.006) and healing rate (HR = 1.001, 1.000 to 1.003,P = 0.042) after adjusting for age, sex, type of diabetes, duration of diabetes, duration of DFU, history of stroke, history of CAD, PAD, HbA1c, serum creatine and urine protein excretion in 24 hours. Conclusion: UA might exert a beneficial effect in the context of DFU wound repair, but was an important risk factor for NNCE and all-cause mortality in patients with DFU.