Risk factors for progression of renal disease in patient with diabetic nephropathy.

AIM: The aim of this study was to investigate the annual rate of glomerular filtration rate (GFR) decline and associated risk factors with this decline in diabetic nephropathy patients.

PATIENTS AND METHODS: A total of 122 type 2 diabetes mellitus (DM) patients (66F, mean follow up time 39 +/- 19 months, mean age 56 +/- 10 years, mean duration of diabetes diagnosis 12.1 +/- 9.5 years) between 2003 and 2010 were evaluated retrospectively. Socio-demographic characteristics and blood pressure data, laboratory parameters, HbAlc, daily urine protein excretion both of the first and last visits of all patients were recorded. Patients were separated into three groups according to rate of GFR decline. Group 1 (n:35), group 2 (n:42) and group 3 (n:45) consisted of patients < 1 ml/dk/1.73 m2, 1-5 ml/dk/1.73 m2 and > 5 ml/dk/1.73 m2 annual rate of GFR decline respectively. Demographics, laboratory data and their treatments were compared in all three groups and were investigated factors that may influence the rate of GFR decline.

RESULTS: The annual rate of GFR decline was 1.4 +/- 2.3 ml/sec, -2.9 +/- 1.0 ml/sec and -11.9 +/- 9.1 ml/sec in group 1, 2 and 3 respectively. Daily urine protein excretion was 0.9 +/- 1.3, 1.2 +/- 1.5 and 5.2 +/- 5.5 g in groups respectively, was found significantly higher in group 3 (p < 0.001). Serum albumin level was significantly lower in group 3 (p < 0.001). We found positive correlation between annual rate of GFR decline and last visit systolic blood pressure (SBP), daily proteinuria and parathormone levels (r: 0.339, 0.447 and 0.289 p < 0.001, < 0.001 and 0.02 respectively) and negative correlation between GFR decline and deltaSBP (delta systolic blood pressure), pretreatment albumin, calcium and hemoglobin levels (r: -0.409, -0.526, -0.233 and -0.467, p < 0.001, < 0.001, < 0.001 and 0.016 respectively).

CONCLUSIONS: Proteinuria, hypoalbuminemia, anemia, and a change in SBP were found most effective in annual rate of GFR decline in patients with diabetic nephropathy. The early detection of these factors may slow the progression of nephropathy.