Prognostic factors and validation of the histologic chronicity score for C3 glomerulopathy: a registry analysis
Şafak Mirioğlu, Egemen Cebeci, Halil Yazıcı, Ülver Derici, Gülizar Manga Şahin, Ganime Çoban, Necmi Eren, Özkan Güngör, Fatih Dede, Tamer Dincer, Kültiğin Türkmen, Taner Baştürk, Murat Duranay, Hakkı Arikan, Onur Tunca, Ömer Celal Elçioğlu, Erhan Tatar, Zeki Aydın, Deren Oygar, Serap Demir, Mehmet Tanrısev, İlhan Kurultak, Aysegul Oruc, Aydın Türkmen, Ömer Faruk Akçay, Hakkı Çetinkaya, Savaş Öztürk, the Glomerular Diseases Working Group of the Turkish Society of Nephrology (TSN-GOLD), Yasemin Özlük, İpek Işık Gönül, Gülistan Gümrükçü, Çiğdem Vural, Emine Kilinc Gunay, Aysel Çolak, İclal Gürses, Hacı Hasan Esen, Ayşim Özağarı, Saba Kiremitçi, Handan Kaya, Çiğdem Özdemir, Funda Taşlı, Arzu Saglam Ayhan, Yasemin Yuyucu Karabulut, Neslihan Guney, Ufuk Usta, Berna Aytaç Vuruşkan
Abstract
ABSTRACT Background Data on the prognostic factors for C3 glomerulopathy (C3G) are limited, and validation of the new C3G histologic index (C3G-HI) in different settings is still needed. We aimed to evaluate the chronicity score of C3G-HI and probable prognostic factors in our population. Methods In this registry study, 74 patients from 20 centers with adequate follow-up data were included. Total chronicity score (TCS) was calculated according to percentages of glomerulosclerosis, interstitial fibrosis, tubular atrophy, and presence of arterio- and arteriolosclerosis. Primary composite outcome was defined as doubling of serum creatinine from baseline, undergoing dialysis or transplantation, development of stage 5 chronic kidney disease, or death. Results Median age was 34 [interquartile range (IQR) 24–46] years, and 39 patients (52.7%) were male. Median follow-up duration was 36 (IQR 12–60) months, and median TCS was 3 (IQR 1–5). Overall, 19 patients (25.7%) experienced primary composite outcome. Multivariate Cox regression model showed that only hemoglobin [adjusted HR (aHR) 0.67, 95% confidence interval 0.46–0.97, P = .035] predicted primary composite outcome, and TCS fell short of the statistical significance (aHR 1.26, 0.97–1.64, P = .08). Receiver operating characteristic analysis demonstrated that TCS showed an area under the curve value of 0.68 (0.56–0.78, P = .028) in discriminating primary composite outcome at 3 years, and 3-year kidney survival was lower in patients with TCS ≥4 (72.4%) compared with TCS <4 (91.1%) in Kaplan–Meier analysis (P = .036). Conclusions Low hemoglobin levels predicted dismal outcomes in patients with C3G. TCS ≥4 was associated with a worse 3-year kidney survival, which validated the 3-year prognostic value of the TCS of C3G-HI in our population.