Comparison of various renal function assessment methods in patients with arterial hypertension

Aim. To evaluate the role of calculated glomerular filtration rate (GFR), microalbuminuria (MAU) and cystatin C assessment in renal pathology diagnostics among patients with arterial hypertension (AH) and normal or mildly elevated serum creatinine level. Material and methods. In 114 non-diabetic patients with non-treated AH (age 53,2 +/- 1,0 years, creatinine 94,3 +/- 1,7 mkmol/l) and 158 patients with AH and diabetes mellitus, DM (age 56,2 +/- 0,7 years, creatinine 81,6 +/- 1,2 mkmol/l), serum creatinine, MAU by albumin/urine creatinine ratio, and calculated GFR by Cockroft-Gault and MDRD formulas (GFR1, GFR2) were assessed. In patients with AH and DM, cystatin C level was also measured. Results. Among non-diabetic AH patients with normal creatinine level, decreased GFR2 < 60 ml/min/1,73 m(2) but no GFR1 reduction < 60 ml/min/1,73 m(2) was observed in 18,8%. MAU was registered in 7 non-diabetic AH patients (6,1%); in one participant, MAU was combined with decreased GFR2 < 60 ml/min/1,73 m(2). Based on serum creatinine, MAU and GFR2 or GFR1 measurement, subclinical renal pathology was diagnosed in 42,1% or 21,9% non-diabetic AH participants, respectively. Among subjects with AH and DM, MAU was observed in 12 (7,6%); in all patients with MAU creatinine level was normal; in 2 patients GFR2 was reduced < 60 ml/min 1,73 m(2). In AH + DM group, cystatin C level was inversely related to GFR2 (r=-0,72; p < 0,001), but not to GFR1. Conclusion. Combined measurement of serum creatinine, MAU and GFR levels improves the diagnostics of subclinical renal pathology in AH patients. In patients with AH and DM, cystatin C is sensitive to early renal dysfunction.