Histopathological Findings Predict Renal Recovery in Severe ANCA-Associated Vasculitis Requiring Intensive Care Treatment

Abstract

Renal involvement is a common and severe complication of AAV as it can cause ESRD. Histopathological subgrouping and ARRS are helpful to predict long-term ESRD in patients with AAV. Because a subgroup of critically ill patients with severe AAV present with deterioration of kidney function requiring RRT at admission, we here aimed to evaluate histopathological findings and predictive value of Berden's histopathological subgrouping and ARRS for severity of AKI and requirement of RRT during the short-term clinical course in critically ill patients requiring intensive care treatment and predictors for short-term renal recovery in patients requiring RRT. A subgroup of 15/46 (32. 6%) AAV patients with biopsy-proven AAV required RRT during the short-term course of disease, associated with requirement of critical care treatment. While histopathological subgrouping and ARRS were associated with requirement of acute RRT, presence of global glomerular scarring was the strongest predictor of failure to recover from RRT after initiation of remission induction therapy. This new aspect requires further investigation in a prospective controlled setting for therapeutic decision making especially in this subgroup.

Keywords: ANCA-associated vasculitis; acute kidney injury; autoimmune diseases; inflammation; intensive care treatment; renal replacement therapy; systemic vasculitis.

Figure 1

Histopathological findings associate with severity of acute kidney injury in severe AAV. (A) Association between requirement of RRT within 30 days after admission; clinical/laboratory and histopathological findings is shown by a heat map reflecting mean values of Spearman's ρ, asterisks indicate p < 0.05. (B–G) Cutoff points on the ROC that maximized Youden's index were used for cumulative incidence of RRT within 30 days after admission for each parameter. (H,I) Histopathological subgrouping and ARRS for successful recovery from RRT within 30 days are shown. Analysis was performed using log rank (Mantel–Cox) testing. ANCA, anti-neutrophil cytoplasmic antibodies; ARRS, ANCA renal risk score; CI, confidence interval; CRP, C-reactive protein; GFR, glomerular filtration rate (CKD-EPI); HR, hazard ratio; IF/TA, interstitial fibrosis/tubular atrophy; RRT, renal replacement therapy; SAPS II, simplified acute physiology score II; uACR, urinary albumin/creatinine ratio.

Figure 2

Global glomerular sclerosis associates with failure to recover from RRT in critically ill patients. (A) Association between successful recovery from RRT within 30 days after RRT initiation; clinical/laboratory and histopathological findings are shown by heat map reflecting mean values of Spearman's ρ, asterisks indicate p < 0.05. (B–E) Cutoff points on the ROC that maximized Youden's index were used for cumulative incidence of successful recovery from RRT within 30 days after RRT initiation for each parameter. (F,G) Histopathological subgrouping and ARRS for successful recovery from RRT within 30 days after RRT initiation are shown. Analysis was performed using log rank (Mantel–Cox) testing. ANCA, anti-neutrophil cytoplasmic antibodies; ARRS, ANCA renal risk score; CI, confidence interval; CRP, C-reactive protein; GFR, glomerular filtration rate (CKD-EPI); HR, hazard ratio; IF/TA, interstitial fibrosis/tubular atrophy; RRT, renal replacement therapy; SAPS II, simplified acute physiology score II; uACR, urinary albumin/creatinine ratio.