MO205: The Outcome of Patients Without Nephrotic Syndrome (NS) is Not Different From Patients With NS, WHO Were Diagnosed as Minimal Change Lesion

Abstract BACKGROUND AND AIMS Minimal change lesion (MCD) accounts for 10–15% of adult patients with nephrotic syndrome and is characterized by edema, nephrotic-ranged proteinuria (NP) and pathologic findings of nearly normal appearance of glomeruli on light microscopy, minimal staining of immunoglobins and extensive effacement of foot process of the podocyte. However, the fate of MCD with typical pathologic findings without nephrotic proteinuria (Non-NP) needs to be defined in more details. METHOD We enrolled 79 adult MCD patients with the first renal biopsy in a tertiary teaching hospital from May 2003 to June 2017. We did not include patients having any immunosuppressive treatment before renal biopsy, patients with inappropriate biopsy samples (<10 glomeruli/biopsy, any electron dense deposit, and light microscopic findings suggestive of secondary causes). Remission of proteinuria was defined as urine protein-to-creatinine ratio (UPCR) < 0.3 g/g creatinine and recurrence of proteinuria as UPCR ≥ 3.0 g/g creatinine. We compared the clinic-pathologic features of MCD with or without NP at admission for renal biopsy, the frequency of flare to nephrotic proteinuria and the renal failure which was defined as decrease of estimated glomerular filtration rate (GFR) more than 50% compared to GFR at renal biopsy, GFR less than 15 mL/min/1.73 m2 or progressed to end-stage renal disease during follow-up period. RESULTS There were 3 patients with UPCR < 0.3 g/g creatinine, 17 patients with UPCR 0.3–2.9 g/g creatinine and 59 patients with UPCR ≥ 3.0 g/g creatinine at admission for renal biopsy. Mean age at renal biopsy was 53.7 ± 19.2 (range:18.5–99.0) years, and there were 38 male patients (48.1%). Non-NP group had lower UPCR (1.36 ± 0.99 versus 10.2 ± 6.21 g/g creatinine, P < .001) and higher GFR (98 ± 27 versus 75 ± 36 mL/min/1.73 m2 P = .012) at renal biopsy, and lower frequency of acute kidney injury during follow-up period [1/20 (5.0%) versus 35/59 (59.3%) patients, P < .001]. NP group showed more severe foot process effacement and interstitial changes. Other clinic-pathologic findings were not different between groups. During follow-up period (63.2 ± 50.4 months), eight patients (40.0%) had recurrence of proteinuria and nine patients (45.0%) had steroid treatment in non-NP group. Among NP group, 55 patients (93.2%) had been treated by steroid. The peak dose of prednisolone for patients having steroid treatment was not different between groups (Non-NP versus NP: 0.92 ± 0.16 mg/kg/day versus 0.88 ± 0.17 mg/kg/day, P = .491). The remission rate by the first treatment of steroid was not different between groups (non-NP versus NP: 9/9 versus 50/55, P = 1.000). The recurrence of proteinuria was developed in 8/9 non-NP patients (88.9%) and in 25/50 (50.0%) NP patients after the first remission of proteinuria by steroid treatment (P = .282). Recurrence of proteinuria was developed 0.23 ± 0.33 times/year in Non-NP group and 0.25 ± 0.41 times/year in NP group (P = .830). At the last follow-up period, the final remission rate of proteinuria was not different [65.0% of non-NP patients (17/20) versus 76.5% of NP patients (45/59), P = .384], and the rate of renal failure was not different, neither [15.0% of non-NP patients (3/20) versus 27.1% of NP patients (16/59), P = .371]. CONCLUSION The adult MCD patients with non-nephrotic-ranged proteinuria at renal biopsy showed similar clinical outcomes compared with patients with nephrotic-ranged proteinuria. Therefore, the MCD pathology should be paid more attention regardless of the amount of proteinuria at renal biopsy.