Sehoon Park1,2, Chung Hee Baek3, Su-Kil Park3, Hee Gyung Kang4, Hye Sun Hyun5, Eujin Park6, Seung Hyeok Han7, Dong-Ryeol Ryu8, Dong Ki Kim1,9,10, Kook-Hwan Oh1,10, Kwon Wook Joo1,9,10, Yon Su Kim1,2,11,10, Kyung Chul Moon9,12, Ho Jun Chin9,10,11, Hajeong Lee13,14. 1. Division of Nephrology, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea. 2. Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea. 3. Division of Nephrology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 4. Department of Pediatrics, Seoul National University Hospital, Seoul, Republic of Korea. 5. Department of Pediatrics, St. Vincent's Hospital, The Cathollic University College of Medicine, Suwon, Republic of Korea. 6. Department of Pediatrics, Kangnam Sacred Heart Hospital, Seoul, Republic of Korea. 7. Division of Nephrology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea. 8. Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, Republic of Korea. 9. Kidney Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. 10. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea. 11. Division of Nephrology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul, Republic of Korea. 12. Department of Pathology, Seoul National University Hospital, Seoul, Republic of Korea. 13. Division of Nephrology, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea, mdhjlee@gmail.com. 14. Kidney Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea, mdhjlee@gmail.com.
Abstract
BACKGROUND/AIMS: Additional validation study was warranted to confirm the clinical significance of C score, which was recently added to the Oxford classification for immunoglobulin A nephropathy (IgAN). METHODS: We performed a multicenter retrospective cohort study in four hospitals in Korea. Patients who had biopsied glomeruli less than eight or inadequate follow-up information were excluded. Clinicopathologic parameters, including the degree of cellular or fibrocellular crescents, were collected and included in multivariable models for Cox regression analysis. The main outcome was a composite renal outcome, defined as a merge of progression to end-stage renal disease (ESRD) and halving of estimated glomerular filtration rate (eGFR) from baseline. RESULTS: Among included 3,380 biopsy-confirmed IgAN patients, there were 664 (19.6%) patients with C1 and 60 (1.8%) patients with C2 scores in the study population. Although C0 and C1 patients shared similar baseline characteristics, C2 patients frequently had more clinicopathologic risk factors for poor prognosis of IgAN. Both C1 [adjusted HR 1.33 (1.11-1.58), P=0.002] and C2 [adjusted HR 2.24 (1.46-3.43), P< 0.001] scores were associated with an increased risk of the composite outcome. C2 was a strong predictive parameter associated with both progression to ESRD and halving of eGFR, whereas C1 was mainly associated with the increased risk of halving of eGFR. Notably, the proportion of crescent showed a linear association with the risk of adverse renal outcome. CONCLUSION: The C score in the Oxford classification is a valid predictive parameter for IgAN prognosis. Additional clinical attention is necessary for IgAN patients with identified cellular or fibrocellular crescents.
BACKGROUND/AIMS: Additional validation study was warranted to confirm the clinical significance of C score, which was recently added to the Oxford classification for immunoglobulin A nephropathy (IgAN). METHODS: We performed a multicenter retrospective cohort study in four hospitals in Korea. Patients who had biopsied glomeruli less than eight or inadequate follow-up information were excluded. Clinicopathologic parameters, including the degree of cellular or fibrocellular crescents, were collected and included in multivariable models for Cox regression analysis. The main outcome was a composite renal outcome, defined as a merge of progression to end-stage renal disease (ESRD) and halving of estimated glomerular filtration rate (eGFR) from baseline. RESULTS: Among included 3,380 biopsy-confirmed IgANpatients, there were 664 (19.6%) patients with C1 and 60 (1.8%) patients with C2 scores in the study population. Although C0 and C1 patients shared similar baseline characteristics, C2 patients frequently had more clinicopathologic risk factors for poor prognosis of IgAN. Both C1 [adjusted HR 1.33 (1.11-1.58), P=0.002] and C2 [adjusted HR 2.24 (1.46-3.43), P< 0.001] scores were associated with an increased risk of the composite outcome. C2 was a strong predictive parameter associated with both progression to ESRD and halving of eGFR, whereas C1 was mainly associated with the increased risk of halving of eGFR. Notably, the proportion of crescent showed a linear association with the risk of adverse renal outcome. CONCLUSION: The C score in the Oxford classification is a valid predictive parameter for IgAN prognosis. Additional clinical attention is necessary for IgANpatients with identified cellular or fibrocellular crescents.