Effects of the Clinical and Biochemical Features of Patients with Treatment-Resistant Primary Nephrotic Syndrome on Renal Survival

OBJECTIVE: Nephrotic syndrome (NS) is commonly associated with progression of chronic kidney disease (CKD). Resistance to treatment is an important problem that is a poor prognostic factor for progression of CKD. Herein, we aimed to investigate the effects of clinical and biochemical parameters on renal survival in patients with treatment-resistant primary NS.

MATERIAL and METHODS: A total of 1305 NS cases who were followed were evaluated. Fifty primary NS patients (M/F: 32/18, mean age: 50±16) who had persistent proteinuria>3.5g/day despite treatment were included.

RESULTS: NS etiologies were as follows: membranous nephropathy (MN), 19 (38%); focal segmental glomerulosclerosis (FSGS), 16 (32%); IgA nephropathy (IgAN), 8 (16%) and membranoproliferative glomerulonephritis (MPGN), 7 (14%). Baseline GFR values were significantly lower in patients with IgAN [37(23-57) mL/min]. Annual rate of decline in GFR levels (∆GFR/year) was not different between the groups. Proteinuria was significantly associated with ∆GFR/year in patients with FSGS (r=-0.51, p=0.04). Baseline C-reactive-protein (CRP) levels were found to be correlated with ∆GFR/year in the MPGN group (r=-0.75,p=0.04). Smoking, hyperlipidemia and treatment had no effect on ΔGFR/years.

CONCLUSION: MN was the most frequent etiological factor in treatment-resistant primary NS. ∆GFR/year was similar in different types of glomerulonephritis. Treatment had no effect on renal survival. Proteinuria in FSGS and CRP in MPGN may predict progression of CKD.