Application of Various Equations for Estimating GFR in Patients with Type 1 Diabetes
American Journal of Internal Medicine
To compare different methods of estimating glomerular filtration rate (GFR) calculated by creatinine and cystatin C in patients with type 1 diabetes with normal and moderately decreased renal filtration function. The study involved 57 patients with type 1 diabetes, 37 men and 20 women, aged from 21 to 57 years (median 30 years), with disease duration after diagnosis from 33 to 2 years (median 8 years). The control group comprised 15 non-diabetic people aged 19 to 42 years (median -28 years),
... dian -28 years), with normal levels of albuminuria and blood creatinine. The majority of patients with type 1 diabetes were found to have decompensated diabetes mellitus. The mean value of glycated hemoglobin in patients was 8%. The renal glomerular function was estimated by level of GFR and triple testing of urine albumin excretion. Renal tubular function in type 1 diabetes was tested by examining serum cystatin C. GFR estimating equations, which did not include serum of cystatin C produced higher GFR. As a result, the majority of patients had normal or elevated GFR showing hyperfiltration. Using cystatin-C-based equations resulted in a several-fold reduction in the number of patients with hyperfiltration and increased number of cases with GFR below 90 ml/min/m 2 . The assessment of the relationship between SDMA and GFR showed negative correlation with both cystatin-C-based and creatinine-based equations. These findings revealed that GFR estimating equations based on both creatinine and cystatin C produce more accurate results compared with the reference estimating equations.