Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy
Fernando Caravaca‐Fontán, Marta Rivero, Teresa Cavero, Montserrat M. Díaz Encarnación, Virginia Cabello, Gema Ariceta, Luís F. Quintana, Helena Marco, Xoana Barros, Natàlia Ramos, Nuria Rodríguez-Mendiola, Sonia Cruz, Gema Fernández‐Juárez, A. Bernardos Rodríguez, Ana Pérez de José, Cristina Rabasco, Raquél Rodado, Loreto Fernández, María Vanessa Pérez-Gómez, Ana Ávila, Luis Eduardo Bravo, N. Espinosa, Natalia Allende, María Dolores Sánchez de la Nieta, Eva Rodríguez, Teresa Olea, Marta Melgosa, Ana Huerta, Rosa Miquel, Carmen Mon, Gloria Fraga, Alberto de Lorenzo, Juliana Draibe, Fayna González, Amir Shabaka, Maria Esperanza López-Rubio, María Ángeles Fenollosa, Luis Martín‐Penagos, Iara Da Silva, Juana Alonso Titos, Santiago Rodrı́guez de Córdoba, Elena Goicoechea de Jorge, Manuel Praga
Abstract
Background: C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival. Methods: = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets. Results: The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24-112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834-0.887) and calibration plots showed optimal agreement between predicted and observed outcomes. Conclusions: We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.