Impact of renal involvement on survival in ANCA-associated vasculitis

Renal involvement is a serious complication of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). We describe the pattern of renal involvement and its correlation with outcomes.

Medical records of 92 patients seen in rheumatology clinic and diagnosed as AAV between January 2007 and June 2014 were analysed. Patients were classified as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA) and undifferentiated AAV. Overall and renal outcomes were analysed. Patients were classified as advanced renal failure (creatinine >5.7 mg/dl or requiring dialysis), deranged RFT not qualifying the above parameters, and normal renal function.

Sixty-seven (72.8 %) patients had GPA, 14 (15.2 %) had MPA, 8 (8.7 %) had EGPA, and 3 (3.3 %) had undifferentiated AAV. Renal involvement was seen in 51 (55.4 %) patients (46.3 % of GPA patients, 78.6 % of MPA, 37.5 % of EGPA and 33.3 % of unclassifiable AAV patients). Renal involvement was more common in males (p = 0.008). Patients with renal involvement had higher mean BVAS scores as compared to patients without renal involvement (p < 0.01). Thirteen patients (25.5 %) presented with advanced renal failure (creatinine >5.7 mg/dl or requiring dialysis), 21 (41.2 %) had deranged renal functions but did not require dialysis, and the rest had proteinuria and active sediments with normal serum creatinine. Twenty-four patients (47.1 %) had good renal outcome with normal creatinine, 12 (23.5 %) had persistent renal insufficiency, 12 (23.5 %) died, and one (2 %) remained dialysis dependent. Mean survival and mortality did not differ in patients with and without renal involvement (p = 0.454, p = 0.388).

Renal involvement was more common in males. BVAS was higher in patients with renal involvement. The mean survival and mortality were similar in patients with or without renal involvement.