Long-Term Outcomes of C3 Glomerulopathy and Immune-Complex Membranoproliferative Glomerulonephritis in Children
Amrit Kirpalani, Natasha Jawa, William E. Smoyer, Christoph Licht, Gina‐Marie Barletta, Sharon Bartosh, Neal B. Blatt, Tom Blydt‐Hansen, Patrick D. Brophy, Lawrence Copelovitch, Bradley P. Dixon, Anne Durkan, Matthew Eison, Larry A. Greenbaum, Guillermo Hidalgo, Deborah P. Jones, Mini Michael, John T. Sanders, Donald J. Weaver, Amy C. Wilson
Abstract
IntroductionThe reclassification of membranoproliferative glomerulonephritis (MPGN) into immune-complex MPGN (IC-MPGN) and C3 glomerulopathy (C3G) has provided insights into 2 distinct diseases. Although outcomes in adults are poor in both diseases, the pediatric literature is scarce and limited to small, single-center cohorts.MethodsWe conducted a retrospective analysis of 165 pediatric patients across 17 hospitals to compare outcomes between children with IC-MPGN and C3G.ResultsForty-two percent of patients initially diagnosed with MPGN were reclassified as C3G after a review of renal biopsy reports. There was a trend toward higher serum creatinine levels in patients with C3G compared with IC-MPGN both at diagnosis (mean 168.9 [range 45.4–292.4] vs. 93.7 [range 70.7–116.6] μmol/l, P = 0.25) and after a mean follow-up time of 4 years (mean 145.0 (range −8.1 to 298.1) vs 99.1 (range 46.3–151.9) μmol/l, P = 0.47), although the estimated glomerular filtration rate (eGFR) was not significantly different. Steroid treatment was associated with a significant improvement in eGFR versus no steroids in C3G (mean +43.0 (range 12.9–73.0) vs. −3.0 (range −23.1 to 17.2) ml/min per 1.73 m2, P = 0.02) but not in IC-MPGN. Overall kidney function was preserved in both groups although hypertension remained prevalent in 42.5% of the cohort at the last follow-up, and the urine protein/creatinine ratio remained elevated (mean 253.8 [range 91.9–415.7] mg/mmol).ConclusionThis large pediatric IC-MPGN/C3G cohort revealed nearly half of the patients were misclassified, and there may be a trend toward worse renal prognosis in C3G although they may have greater steroid responsiveness. The overall prognosis appears to be more favorable than in adults; however, persistent hypertension and proteinuria suggest suboptimal disease control.