[If the level of cystatin C in children and adolescents with type 1 diabetes an early marker for diabetic nephropathy?].

Background: The most important complication in the course of diabetes mellitus type I is diabetic nephropathy. Nowadays, apart from assessing the increased amount of albumins in urine, we are not able to identify early enough these patients whose health might be endangered by nephropathy. Looking for other biochemical indicators which could mark the early symptoms of kidney damage/renal malfunction seems to be justified.

Objectives: 1. What is the concentration of cystatin C among children and teenagers suffering from diabetes mellitus type 1 and whether its level depends on the age of patient, the age in which the patient was affected with the disease, the length of the disease, metabolic compensation, diabetes control and the presence of microangiopathy? 2. Is there any interdependence between cystatin C and microalbuminuria and the renal efficiency rates?

Material: Study group. A group of 130 patients (60 girls and 70 boys aged from 7 and 20,8) who have been suffering from juvenile diabetes from 1 to 17 years was examined. The control group were healthy youngsters, matched for age and sex, without any /burdening/ medical history.

Methods: All the patients were examined in the following way: anthropometric measurements were taken, BMI in kg/m2 was defined, metabolic compensation based on HbA1c (%) was estimated. Ophthalmological examination and a circadian monitoring of arterial blood pressure were carried out. Microalbuminuria in a 24-hour urine collection was determined. In both groups glomerular filtration rate with the help of endogenous creatinine clearance and the concentration of cystatin C were evaluated. The results were subject to statistical analysis.

Results: The average age of the whole examined group was 15+/-3,0 the average disease length 6,85+/-3,36 years. The concentration of cystatin C among diabetic patients was higher in comparison with the control group (0.75+/-0.13 vs. 0.68+/-0.12 mg/l). It was also discovered that the concentration of cystatin C was increasing along with the length of the disease reaching the highest level in the group of patients suffering from this disease longer than 10 years (0.52+/-0.11 vs. 0.67+/-0.13 vs. 0.93+/-0.13 mg/l), which is again statistically significant. Moreover the concentration of cystatin C is higher among patients with insufficient diabetes control (0.765+/-0.12 mg/l vs. 0.71+/-0.12 pg/ml, p<0.05). These patients who additionally developed vascular complications (retinopathy, nephropathy, arterial hypertension) had significantly higher condensation of cystatin C (0.75+/-0.13 vs. 0.69+/-0.11 mg/l, p<0.05).

Discussion: Having considered the initial results, the following conclusion can be reached: only further, long-term research can supply us with the reliable data whether assessing the level of cystatin C concentration in children's and teenagers' serum in diabetic patients could become the earlier marker of renal malfunction than microalbuminuria.