Relationship between serum uric acid and bone mineral density in patients with type 2 diabetic nephropathy and normal renal function

Objective To retrospectively investigate the relationship between serum uric acid (SUA) and bone mineral density(BMD) in patients with type 2 diabetic nephropathy and normal renal function. Methods A total of 115 patients with type 2 diabetic nephropathy and normal renal function visiting Department of Endocrinology and Department of Nephropathy of Shandong Province Qingdao Chengyang People's Hospital were recruited. Their clinical data were collected to conduct retrospective analysis. The patients were divided into three groups according to the tertile principle and SUA levels:low SUA group(n=39), medium SUA group(n=38) and high SUA group(n=38). Routine blood biochemical parameters, serum albumin, creatinine, urea nitrogen, SUA, calcium, phosphorus, BMD in lumbar vertebra 1-4, BMD in the femur and BMD in the Wards triangular zone of the femur were assayed. Changes of the above parameters in the 3 groups were observed to analyze the correlations of SUA with the other indices. Results SUA (F=211.355, P<0.001), total cholesterol (F=3.678, P=0.028), triglyceride (F=4.397, P=0.015), lumbar_1-4 BMD (F=3.124, P=0.048), femoral BMD (F=5.038, P=0.008), femur wards triangle BMD (F=3.339, P=0.039), femur fat content (F=3.374, P=0.038) and femur muscle content (F=3.413, P=0.036) have statistically significant differences among the low, middle and high SUA groups. Correlation study revealed that SUA level was positively correlated with total cholesterol(r=0.248, P=0.008), triglyceride(r=0.341, P<0.001), lumbar_1-4 BMD(r=0.220, P=0.018) and femoral BMD(r=0.227, P=0.015). Multivariate regression analysis results showed that SUA was an independent protective factor for lumbar1-4 BMD(β=4.54×10^-4, P=0.018), femoral BMD(β=4.52×10^-4, P=0.015) and femur Wards triangle BMD(β=0.001, P=0.019). Conclusions SUA can increase the BMD value in patients with type 2 diabetic nephropathy and normal renal function patients, which may reduce bone loss via the inhibition of oxidative stress.