External validation of the international prediction tool in Korean patients with immunoglobulin A nephropathy

Young Su Joo, Hyung Woo Kim, Chung Hee Baek, Jung Tak Park, Hajeong Lee, Beom Jin Lim, Tae Hyun Yoo, Kyung Chul Moon, Ho Jun Chin, Shin Wook Kang, Seung Hyeok Han

Research output: Contribution to journalArticlepeer-review


Background: The International IgA Nephropathy Prediction Tool has been recently developed to estimate the progression risk of im-munoglobulin A nephropathy (IgAN). This study aimed to evaluate the clinical performance of this prediction tool in a large IgAN cohort in Korea. Methods: The study cohort was comprised of 2,064 patients with biopsy-proven IgAN from four medical centers between March 2012 and September 2021. We calculated the predicted risk for each patient. The primary outcome was occurrence of a 50% decline in estimated glomerular filtration rate (eGFR) from the time of biopsy or end-stage kidney disease. The model performance was evalu-ated for discrimination, calibration, and reclassification. We also constructed and tested an additional model with a new coefficient for the Korean race. Results: During a median follow-up period of 3.8 years (interquartile range, 1.8–6.6 years), 363 patients developed the primary out-come. The two prediction models exhibited good discrimination power, with a C-statistic of 0.81. The two models generally underesti-mated the risk of the primary outcome, with lesser underestimation for the model with race. The model with race showed better performance in reclassification compared to the model without race (net reclassification index, 0.13). The updated model with the Korean coefficient showed good agreement between predicted risk and observed outcome. Conclusion: In Korean IgAN patients, International IgA Nephropathy Prediction Tool had good discrimination power but underestimat-ed the risk of progression. The updated model with the Korean coefficient showed acceptable calibration and warrants external vali-dation.

Original languageEnglish
Pages (from-to)556-566
Number of pages11
JournalKidney Research and Clinical Practice
Issue number5
Publication statusPublished - 2022 Sept 1

Bibliographical note

Funding Information:
This study was supported by a cooperative research fund from the Korean Nephrology Research Foundation (2021). The sponsor had no role in the study design, data collection, or analysis.

Publisher Copyright:
© 2022 by The Korean Society of Nephrology.

All Science Journal Classification (ASJC) codes

  • Nephrology
  • Urology


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