[Functional state of kidneys and cardiovascular risk in patients with urolithiasis in an outpatient setting]

To analyze the functional state of the kidneys and vascular stiffness in patients with urinary stone disease in an outpatient setting.

A total of 110 patients with urinary stone disease aged 17-72 years were included in the study. The stone size was 2,67 (1,90-3,49) mm. A clinical examination included evaluation of vascular stiffness, serum level of creatinine, cystatin C, calcium, phosphorus, sodium, magnesium, uric acid and total cholesterol. The glomerular filtration rate (eGFR) was calculated based on the formulas CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) and MDRD (Modification of Diet in Renal Disease) and Hoek's equations using creatinine and cystatin C, respectively.

Most often, urinary stone disease was associated with arterial hypertension (75%), a sedentary lifestyle (66.3%), hypercholesterolemia (53.6%), obesity (47.2%), hyperuricemia (44.5%) and smoking (40.9%). The median and interquartile range of eGFR according to CKD-EPI, MDRD and Hoek's equations was 100.00 (78.00;113.00) ml/min, 96.00 (71.00;106.00) ml/min and 77.65 (61.50; 93.60) ml/min, respectively. The normal GFR was significantly more often detected by the formula CKD-EPI (66.3%) in comparison with the Hoek's equations (52.7%), p<0.05. A decrease in mild GFR was found in 21 (19.0%) patients according to CKD-EPI and 33 (30.0%) according to Hoek's equations (p<0.05). In the subgroup of patients with a mild to moderate decrease in GFR according to the Hoek's equations, stiffness index and resistive index were significantly higher than in the similar subgroup of patients with decrease of GFR measured using the CKD-EPI formula (p<0.05). A negative correlation between GFR calculated using three formulas and Augmentation Index was established.

In patients with urinary stone disease, potential cardiovascular risk factors are very common. The study of serum cystatin C level with calculation of GFR according to Hoek's equations in individuals with urolithiasis allows to evaluate total renal nitrogen excretion, as well as the level of the cardiovascular risk in the early stages of the disease.