Analysis of risk factors for uric acid nephrolithiasis in type 2 diabetes

Abstract

Type 2 diabetes mellitus (T2DM) is an independent risk factor for uric acid nephrolithiasis, and obesity augments this risk. We carried out this cross-sectional study on 25 patients of T2DM to assess the risk factors for uric acid nephrolithiasis and to assess their relation with components of the metabolic syndrome. A single 24-hour urine sample was analyzed for fasting urine pH, uric acid, creatinine and protein. Fasting serum sample was analyzed for HbA1c, glucose, creatinine, uric acid and lipid profile. Patients with past history of nephrolithiasis and significant hepatic or renal disease were excluded. The mean age of the participants was 51 ± 8.5 years and there were 16 females and nine males. Mean body mass index (BMI) was 27.3 ± 4.3 kg/m 2 and waist circumference was 90.8 ± 7.8 cm. Urinalysis revealed mean uric acid excretion of 595 ± 103 mg/24 hours and fasting urine pH of 5.6 ± 0.4. Fasting urine pH correlated inversely with the body weight, BMI and low density lipoprotein (LDL)-cholesterol (P < 0.05). Total volume showed inverse correlation with age and disease duration and correlated positively with body weight and BMI. Uric acid excretion did not correlate with the components of metabolic syndrome. Our preliminary data showed that low urine pH as the main risk factor for uric acid nephrolithiasis was consistently found in our study patients with T2DM. Higher BMI further accentuates this risk. Further data from more number of patients are necessary to confirm these findings.