Table 1. Demographic and clinical features of patients with systemic lupus erythematosus.

Characteristics	Non-ILD group (n=449)		ILD group (n=56)
	n	%	n	%	χ2	p
Age (year)					13.553	0.001
≤44	319	71.0	28	50
45-59	101	22.5	18	32.1
≥60	29	6.5	10	17.9
Sex
Female	392	87.3	49	87.5	0.002	0.967
Body mass index (kg/m2)				5.348	0.069
<18.5	77	17.1	6	10.7
18.5-23.9	315	70.2	37	66.1
≥24	57	12.7	13	23.2
SLE duration (year)					14.746	0.001
<1	250	55.7	16	28.6
1-10	167	37.2	33	58.9
≥10	32	7.1	7	12.5
Dry cough	100	22.3	18	32.1	2.709	0.1
Moist rales	40	8.9	11	19.6	6.319	0.012
Malar rash	164	36.5	20	35.7	0.014	0.905
Epilepsy	8	1.8	0	0.0	1.014	0.314
Fever	160	35.6	20	35.7	0	0.991
Arthritis	221	49.2	33	58.9	1.877	0.171
Photosensitivity	58	12.9	6	10.7	0.218	0.64
Serositis	112	24.9	10	17.9	1.365	0.243
Neuropsychological involvement	40	8.9	1	1.8	3.386	0.066
Myalgia/myasthenia	11	2.4	2	3.6	0.25	0.617
Xerostomia/xeroma	37	8.2	4	7.1	0.08	0.777
Oral ulcer	41	9.1	6	10.7	0.148	0.701
Raynaud’s phenomenon	49	10.9	19	33.9	22.635	<0.001
Alopecia	60	13.4	9	16.1	0.31	0.578
Livedo reticularis	4	0.9	0	0.0	0.503	0.478
Finger tip vasculitis	17	3.8	3	5.4	0.323	0.57
Peripheral neuritis	7	1.6	0	0.0	0.885	0.347
Malar rash	120	26.7	11	19.6	1.3	0.254
Tachypnea	50	11.1	17	30.4	15.986	<0.001
SLEDAI					5.579	0.134
0-4	140	90.3	15	9.7
5-9	156	85.2	27	14.8
10-14	91	89.2	11	10.8
≥15	62	95.4	3	4.6
SDI					4.845	0.183
0	267	90.8	27	9.2
1	118	86.8	18	3.2
2	31	91.2	3	8.8
≥3	33	80.5	8	19.5
Abnormal electrocardiogram	244	54.3	34	60.7	0.817	0.366
ILD: Interstitial lung disease; SLE: Systemic lupus erythematosus; SLEDAI: Systemic lupus erythematosus disease activity index; SDI: Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index.