AUTHOR=Du Yongjing , Chen Shasha , Wang Fengping , Zhang Ping , Liu Mijia , Liu Chi , Zhong Xiang , Qin Jianhua , Li Guisen , Wang Wei 

TITLE=The Significance of Crescents on the Clinical Features and Outcomes of Primary Immunoglobin A Nephropathy

JOURNAL=Frontiers in Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.864667

DOI=10.3389/fmed.2022.864667

ISSN=2296-858X

ABSTRACT=Aim
To explore the significance of different proportions of crescents on the clinical features and the cut-off value of crescents in predicting the occurrence of end-stage kidney disease (ESKD) in IgAN.
Methods
We retrospectively analyzed biopsy-proven primary IgAN patients in Sichuan Provincial People’s Hospital from 2007 to 2019. The patients were divided into 5 groups on the basis of crescent proportion as follows: 0 (n=647), <10% (n=221), 10% to 24% (n=272), 25% to 49% (n=80), and ≥50% (n=22). A validation cohort of 346 patients were enrolled from Affiliated Hospital of Southwest Medical University. Cox regression model and Kaplan-Meier survival analysis were performed.
Results
1242 eligible patients with biopsy-proven IgAN were recorded in the database, A higher crescent proportion was associated with lower levels of Hb, ALB, eGFR and serum IgG (p<0.05), higher levels of SCr, BUN, increasing amounts of 24h urinary protein, increasing proportion of M1 and E1, and increasing severity of interstitial inflammatory infiltration. During the median follow-up of 43 months (range 6-151), 63 individuals (7.0%) reached the primary outcome of ESKD and 99 patients (11.1%) reached the combined renal endpoint. 34(7.5%), 21 (13.3%), 24(12.2%), 14(21.5%) and 6(31.6%) patients reached the combined renal endpoint in the above five groups in crescents 0, <10%, 10~24%, 25~49% and ≥50%, respectively. Multivariate Cox regression showed that crescents ≥50% was an independent risk factor for the progression of ESKD (p=0.003) and crescents ≥25% was an independent risk factor for the combined renal endpoint(p<0.001). The receiver operating characteristic curve showed that IgAN patients with crescents ≥43.7% had a higher risk of ESKD, even with immunosuppressants (Sensitivity=75.7%,specificity=89.6%,p<0.001). This discovery cohort and the validation cohort further confirmed that patients with crescents <43.7% had better renal prognosis than those with crescents≥43.7% in the whole group and those with immunosuppressants(p<0.001). 
Conclusion
IgAN patients with crescents had more severe clinicopathological features and poorer prognosis. Crescents ≥50% was an independent risk factor for the progression of ESKD and crescents ≥25% was an independent risk factor for ≥50% reduction in eGFR or ESKD in treated and untreated IgAN patients. Crescents≥43.7% was an independent risk factor for ESKD in those with immunosuppressants.