Crescents proportions above 10% are associated with unfavorable kidney outcomes in IgA nephropathy patients with partial crescent formation.

Purpose: Whether different crescentic proportions determine the progression of IgA nephropathy (IgAN) with crescents in less than 50% of glomeruli remains controversial. We aimed to evaluate the relationship between different proportions of crescents and kidney outcomes in IgAN with partial crescent formation.

Methods: Patients diagnosed as IgAN, having at least two crescents and in less than 50% of glomeruli, were categorized into three groups: Group I (crescents in ≤10% of glomeruli), Group II (10%< crescents ≤25% of glomeruli) and Group III (crescents >25% of glomeruli). Baseline clinicopathological parameters were evaluated. The kidney endpoint was a composite of  ≥ 40% decline in the initial estimated glomerular filtration rate, end-stage kidney disease, and kidney disease-related death.

Results: Of 183 IgAN patients with crescents in less than 50% of glomeruli, baseline 24-hour urinary protein and immunosuppressive treatment varied among the three groups ( < 0.05). During a median follow-up of 57 months (interquartile range 28-86), 50 (27.3%) patients reached the composite outcome. Kaplan-Meier survival analysis revealed that kidney survival in Group II ( = 0.049) and Group III ( = 0.008) was significantly shorter than in Group I, with no significant difference between Group II and III ( = 0.2). After adjusting for clinical factors and MEST score based on the multivariate Cox regression analysis, a crescent proportion >10% (HR = 3.431, 95% CI 1.067-11.03,  = 0.039) was predictive of time to unfavorable kidney outcome, with model adjustments improving predictability (c-index: 0.817).

Conclusion: The proportion of crescents reaching 10% of glomeruli in IgAN was identified as an independent risk factor for kidney survival.