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Kidney Week

Abstract: TH-PO582

Histopathology Findings and Outcomes of Non-Nephrotic Range Proteinuria in Adults and Children

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Itoku, Ai, Children's Hospital at Montefiore, New York, New York, United States
  • Bu, Lihong, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Hao, Wei, University of Michigan, Ann Arbor, Michigan, United States
  • Kaskel, Rick, Children's Hospital at Montefiore, New York, New York, United States
  • Pullman, James M., Children's Hospital at Montefiore, New York, New York, United States
  • Reidy, Kimberly J., Montefiore Medical Center, New York, New York, United States
Background

While there are clinical practice recommendations for nephrotic syndrome (NS), the approach to diagnosis and management of non-nephrotic range proteinuria (NNP) is not well defined. We hypothesized that histopathologic diagnosis would differ between subjects with NNP compared to NS, and that renin-angiotensin aldosterone system (RAAS) blockers would be associated with complete or partial remission in subjects with NNP.

Methods

This is a secondary analysis of the Nephrotic Syndrome Study Network (NEPTUNE) cohort. We included adult and pediatric NEPTUNE participants who did not receive treatment for NS prior to screening, and who presented with urine protein creatinine ratio (UPCR) ≧ 0.5 g/g up to < 2 g/g in children and < 3 g/g in adults at the time of screening. A NS comparison group was identified using clinical diagnoses of NS and/or UPC ≧ 2 g/g in children and untreated adults with UPC ≧ 3 g/g at screening. Histopathologic diagnoses were compared by Chi-Square test between NNP and NS cohorts. In longitudinal analyses, we examined the associations of covariates with complete or partial remission and eGFR decline during the follow up period in NNP using generalized estimating equation.

Results

More than half of adult and children presenting with NNP were classified as overweight/obese and had high blood pressure. Subjects presenting with NNP were more likely to have FSGS than those presenting with NS [In adults, 37.1% in NNP vs 29.3 % in NS (p=0.002). In children, 41.2% in NNP vs 18.1% in NS (p<0.0001).] In those with NNP, histopathology diagnosis of FSGS (vs diagnosis of other) [OR=3.27, p=0.03] and/or high blood pressure at baseline [OR=0.51, p=0.02] predicted decrease rate of remission. In those with NNP, histopathology diagnosis of IgAN (vs FSGS) and/or overweight/obesity at baseline predicted faster eGFR decline [-8.63 ml/min/year (p=0.038), -7.04 ml/min/year (p=0.021) respectively]. While this study had a limited sample size, RAAS therapy was not statistically significantly associated with either remission or eGFR in this cohort.

Conclusion

This study supports the need for kidney biopsy in subjects presenting with NNP. Further study/clinical trials are needed to identify the effective therapies for subjects with NNP.