Research Viewpoints Outcomes in Anti-GBM Disease

Viewpoint On

Jia X.-Y., Xu H.-Y., Cui Z., Zhao M.-H.: Predictors of Kidney Outcomes of Anti-Glomerular Basement Membrane Disease in a Large Chinese Cohort. American Journal of Nephrology DOI 10.1159/000512365

Anti-GBM disease poses a serious threat to survival and preservation of kidney function, especially if it is discovered or treated late in its evolution. It is a rare disease (1–3 cases per million per year), so information on outcomes is rather limited.

Jia and colleagues conducted a remarkable, retrospective study of 448 patients with serologically or biopsy-proven anti-GBM disease at a single center in China diagnosed and treated over about a 3-decade period (1991–2020). Of these 448 subjects, 218 underwent a kidney biopsy showing typical linear IgG deposits.

The age of the subjects was 47 ± 19 years. There was a male predominance (1.6 male/female). About one-third had concomitant diffuse alveolar hemorrhage. About 21% had concomitant ANCA positivity. The serum creatinine level at diagnosis was 9.2 ± 5.2 mg/dL, and 83% of the kidney biopsies showed crescents in over 50% of glomeruli. The delay from apparent onset of disease to diagnosis (and presumably treatment) was 1.3 months (interquartile range = 0.9–2.8 months). Plasma exchange (PLEX) was carried out in 56% of patients; 88% received steroids and 67% received cytotoxic agents. The overall renal survival of all patients seen over the 3 decades was only 23%, and the 3-month and 12-month patient mortality was 19% and 31%, respectively. For every 2.3 mg/dL increase in serum creatinine, the risk of kidney failure rose by about 16%.

Over the 30 years covered by this analysis, patient mortality declined (from 37% in 1991–2000 to 2.8% in 2011–2020), but the risk of kidney failure hardly changed at all. The average serum creatinine level at diagnosis was 11.2 mg/dL in 1991–2000 and 9.3 mg/dL in 2011–2020. A serum creatinine level of ≥6.1 mg/dL at diagnosis was highly predictive of eventual dialysis dependency (Sensitivity = 88%; Specificity = 81%). ANCA positivity was predictive of higher mortality but not kidney failure. The use of PLEX was associated with better outcomes. Combined membranous nephropathy and anti-GBM disease increased over the decades.

This detailed analysis of a 3-decade experience in diagnosing and managing anti-GBM disease is a valuable addition to the literature. It is worth pointing out that it applies largely to a subset of patients with anti-GBM disease referred for diagnosis and treatment rather late in the course of the disease. This likely explains the rather poor results in causing remissions without permanent loss of kidney function. It points out again the overriding importance of early recognition and prompt diagnosis (by serology and/or kidney biopsy) and institution of therapy (PLEX, steroids, and cytotoxic agents) for optimizing favorable clinical outcomes.