Integrating nephron number into risk stratification for IgA nephropathy

Area of Science:

• Nephrology
• Biomarker Discovery
• Renal Pathology

Background:

• The International IgA Nephropathy (IgAN) prediction tool currently uses clinical and histopathological data for risk assessment.
• There is a need for additional structural biomarkers to enhance the prognostic accuracy for kidney outcomes in IgAN patients.

Purpose of the Study:

• To investigate if incorporating estimated nephron number improves the predictive performance of the International IgAN prediction tool.
• To evaluate the additive prognostic value of estimated nephron number in IgAN patients.

Main Methods:

• A post hoc analysis of 218 adult IgAN patients with native kidney biopsy was performed.
• Estimated nephron number was calculated using computed tomography and kidney biopsy data.
• The 5-year risk of composite kidney outcomes was assessed using the International IgAN prediction tool, with and without estimated nephron number.

Main Results:

• The addition of estimated nephron number to the prediction tool improved discrimination (C statistic from 0.855 to 0.867).
• Net reclassification improvement (NRI) was significantly enhanced (0.544, P=0.011) after incorporating nephron number.
• The cohort had a mean estimated nephron number of 6.8 × 10^5 per kidney, with 11.5% reaching the composite outcome within 5 years.

Conclusions:

• Estimated nephron number offers significant additive prognostic value in IgAN patients.
• This structural biomarker complements existing predictors for improved risk stratification.
• Estimated nephron number supports enhanced precision in managing IgAN patients.