Updating the International IgA Nephropathy Prediction Tool for use in children

Area of Science:

• Nephrology
• Pediatric Nephrology
• Glomerulonephritis

Background:

• IgA nephropathy (IgAN) is a common cause of glomerulonephritis in children.
• Predicting disease progression in pediatric IgAN is crucial for personalized treatment but currently limited.
• Existing adult prediction tools require adaptation for pediatric use due to differing disease trajectories.

Purpose of the Study:

• To update and validate the International IgAN Prediction Tool for pediatric use.
• To assess the predictive accuracy of the tool for disease progression in children with IgAN.
• To establish a reliable method for risk-stratifying pediatric IgAN patients.

Main Methods:

• Utilized a multiethnic international cohort of 1,060 children with IgAN followed into adulthood.
• Adapted the adult International IgAN Prediction Tool, initially predicting a 50% decline in estimated glomerular filtration rate (eGFR) or end-stage kidney disease (ESKD).
• Re-calibrated the tool using a secondary outcome of a 30% reduction in eGFR or ESKD, evaluating model fit, calibration, and predictive accuracy (C-statistics, R²D).

Main Results:

• The initial adaptation for a 50% eGFR decline showed poor calibration in children.
• Updating the outcome to a 30% eGFR decline or ESKD resulted in good calibration and improved model fit (R²D 30.3%/22.2%, C-statistics 0.74/0.68).
• Pediatric eGFR trajectories differ from adults, showing an initial increase followed by a linear decline, which the updated tool accounts for.

Conclusions:

• The updated pediatric IgAN Prediction Tool accurately predicts the risk of a 30% decline in eGFR or ESKD in children.
• This tool enables personalized, risk-based treatment decisions for pediatric IgAN patients.
• The findings highlight the importance of considering pediatric-specific disease trajectories in prediction modeling.