Diagnostic Value of Cystatin C and I Type IV Collagen in Patients with Hypertension and Obesity

Abstract

Objective: to study the diagnostic value of urinary cystatin C and type IV collagen in hypertensive and obese patients for early diagnosis of renal dysfunction.

Materials and methods. The study included 170 people aged 25-55 years: 90 patients with obesity, metabolic disorders and arterial hypertension (AH) ("complicated obesity"), 50 with obesity without metabolic disorders ("metabolically uncomplicated obesity") and 30 people with hypertension without obesity. The control group consisted of 50 healthy respondents without obesity. Clinical and biochemical parameters, levels of leptin, resistin, adiponectin, cystatin C in blood serum and urine, albuminuria, and collagen IV in urine were studied.

Results. In the groups of AH patients, we found correlations between the level of cystatin C and triglycerides, blood pressure (BP), leptin, resistin, insulin resistance index, and albuminuria. In patients with hypertension, calculation of the glomerular filtration rate (GFR) using the Hoek formula revealed a decrease in renal function at the optimal level of GFR using the CKD-EPI formula. An association was established between serum cystatin C and the degree of obesity, but urinary excretion did not reveal such a relationship. In the obese group without metabolic disorders and hypertension, an increase in urinary excretion of cystatin C was found with normal GFR and albuminuria. In the groups with hypertension, an increase in urinary excretion of type IV collagen and its relationship with albuminuria, blood pressure, and total cholesterol were found.

Conclusion. In patients with hypertension, the relationship of cystatin C in blood and urine with the level of adipokines was established, which confirms the importance of hormonal activity of adipose tissue in the development of glomerular and tubular renal dysfunction. An increase in urinary excretion of type IV collagen in patients with hypertension indicates the initiation of nephrosclerosis processes, and the presence of obesity exacerbates this process.