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Abstract Background and Aims Persisting proteinuria has been associated with worse kidney outcomes in ANCA-associated glomerulonephritis (AAGN). However, it remains unclear whether this reflects damage from the initial injury or ongoing inflammation. Method A retrospective, single centre study of biopsy-proven AAGN. The group “albuminuria” was defined as urine albumin-to-creatinine ratio (ACR) more than 300 mg/g and the group “no albuminuria”, defined as ACR less than or equal to 300 mg/g at 6 months. We sought the clinical and histopathological characteristics from both the initial and any subsequent biopsies, and long-term kidney outcomes stratified by albuminuria levels. Results 218 patients were included. Within the first six months, 28 (13%) had either died or progressed to end-stage kidney disease (ESKD). Among the remaining 190 patients, 37% had an ACR300 mg/g at 6 months. The albuminuria group more frequently presented with a Berden mixed or crescentic class and had higher glomerular activity on the initial biopsy. They were also more often male odds ratio (OR) 2.69; 95% CI 1.13-6.41, of younger age (OR 0.96; 95% CI, 0.93 to 0.99) and had fewer normal glomeruli in the biopsy (OR 0.96; 95% CI, 0.93 to 0.99) compared to the group without albuminuria. Over the initial 5-year period, the recovery in glomerular filtration rate (GFR) was lower in the albuminuria group (adjusted mean difference in delta GFR −12.5 ml/min per 1.73 m2; 95% CI, −15.8 to −9.1). In multivariable analysis, ACR greater than 300 mg/g was associated with a higher risk of ESKD, even after adjusting for age, Berden classification and GFR at diagnosis (Hazard ratio 7.25; 95% CI, 1.62 to 32.47). Conclusion In a well-defined cohort of AAGN, one third of the patients, primarily younger males with a lower percentage of normal glomeruli, had persisting albuminuria after induction treatment which was associated with worse kidney outcomes independent of Berden class and GFR at diagnosis.
Chalkia et al. (Wed,) studied this question.