Classification and characteristics of Japanese patients with antineutrophil cytoplasmic antibody-associated vasculitis in a nationwide, prospective, inception cohort study

Table 1 Comparison of demographics and disease states among AAV diseases

	EGPA	GPA	MPA/RLV	Unclassifiable
	(n = 14)	(n = 33)	(n = 78)	(n = 31)
Male/female	5/9	12/21	35/43	9/22
Mean (median) age (years)^a,c	58.0 ± 16.9 (62)	63.6 ± 12.6 (61)	71.1 ± 10.0 (73)	70.6 ± 11.8 (73)
MPO-ANCA^a,c	7 (50.0)	18 (54.6)	76 (97.4)	29 (93.5)
PR3-ANCA^b,c	0 (0)	15 (45.5)	2 (2.6)	1 (3.2)
ANCA-negative^a,b	7 (50.0)	3 (9.1)	1 (1.3)	2 (6.5)
Serum creatinine (mg/dl)^a	0.71 ± 0.39	1.51 ± 1.32	2.46 ± 2.18	0.69 ± 0.23
Disease severity^c
Localised	0 (0)	4 (12.1)	0 (0)	0 (0)
Early systemic	1 (7.1)	5 (15.1)	15 (19.2)	15 (48.4)
Generalised	13 (92.9)	18 (54.6)	47 (60.3)	13 (41.9)
Severe	0 (0)	6 (18.2)	16 (20.5)	3 (9.7)
General performance^d
0/1/2/3/4	1/7/2/4/0	8/11/2/11/1	10/29/17/16/6	3/11/7/9/1
Nongranulomatous pulmonary involvement
Interstitial lung disease^a	2 (14.3)	3 (9.0)	37 (47.4)	19 (61.3)
Alveolar haemorrhage	0 (0)	2 (6.1)	9 (11.5)	2 (6.5)

Values expressed as mean ± standard deviation or number (percentage) unless otherwise noted. AAV, antineutrophil cytoplasmic antibody-associated vasculitis; ANCA, antineutrophil cytoplasmic antibody; EGPA, eosinophilic granulomatosis with polyangiitis (Churg–Strauss syndrome); GPA, granulomatosis with polyangiitis (Wegener’s granulomatosis); MPA, microscopic polyangiitis; MPO, myeloperoxidase; PR3, proteinase-3; RLV, renal-limited vasculitis. Comparisons between the EGPA, GPA, and MPV/RLV groups were made by Student t test or Mann–Whitney U test. Statistical significance was determined by P < 0.05/3 using Bonferroni correction: ^aEGPA versus MPA/RLV, ^bEGPA versus GPA, ^cGPA versus MPA/RLV. Unclassifiable AAV was not compared with other forms of AAV. ^dGeneral performance was categorised according to the World Health Organization performance status except category 5 (death).