Cystatin C as a Marker of Kidney Function in Patients With Diabetes Mellitus and Purine Metabolism Disorders

Chronic kidney disease is a pressing issue for healthcare systems over the world; its prevalence has reached 13% in Western countries. In recent years, cystatin C has been proposed as a more reliable endogenous marker of renal function, especially for the diagnosis of initial changes in glomerular filtration rate. The aim of this study is to analyze the signs of chronic kidney disease in patients with type 2 diabetes mellitus depending on the level of uricemia by using cystatin C in real clinical practice. The study included 127 patients with type 2 diabetes mellitus (mean age = 60.0 years [52.0; 66.0]; sex ratio: 55 men/ 72 women) who received oral hypoglycemic therapy. All subjects, depending on the stage of diabetic nephropathy were divided into groups: group 1 (n=80) included patients with asymptomatic diabetic nephropathy (normoalbuminuria below 30 mg/day)); group 2 (n=22) involved patients with microalbuminuria (30-300 mg/day); group 3 (n=17) included patients with proteinuria; group 4 (n=8) comprised patients with chronic renal failure. Glomerular filtration rate was calculated according to the formulas of Chronic Kidney Disease Epidemiology Collaboration taking into account the concentration of cystatin C (Chronic Kidney Disease Epidemiology Collaboration cys), by Cockcroft-Gault and Modification of Diet in Renal Disease Study using a calculator of the National Institute of Diabetes and Digestive and Kidney Diseases. In patients with type 2 diabetes mellitus, the development of chronic kidney disease is also predetermined by the following comorbid conditions as hypertension, chronic pyelonephritis, hyperuricemia, and asymptomatic urolithiasis, along with diabetic nephropathy. Glomerular filtration rate values in patients with type 2 diabetes mellitus assessed by Chronic Kidney Disease Epidemiology Collaboration cys are more reliable than those assessed by using the formulas of Cockcroft-Gault and Modification of Diet in Renal Disease Study, especially at the limit level of glomerular filtration rate ˂60 ml/min/1.73m2. In patients with type 2 diabetes mellitus, the level of circulating cystatin C is associated with body mass index, waist circumference, blood uric acid concentration and albuminuria levels. The blood concentration of cystatin C in the patients with type 2 diabetes mellitus is determined by the blood concentration of creatine and uric acid.