Table 2.

Disease characteristics and health-related quality of life stratified by socioeconomic status. Numbers are mean ± SD, median.

Characteristic	Z-AHI (US dollars: unit = 1000)		Education
Characteristic	≤ $35,000/yr	> $35,000/yr	< High School	High School	College/Univ Degree	Graduate Degree
Physician global assessment	1.09 ± 0.83, 1.00	1.11 ± 0.75, 1.00	0.91 ± 0.77, 1.00	1.17 ± 0.84, 1.00	1.14 ± 0.75, 1.00	1.04 ± 0.75, 1.00
SLEDAI	6.50 ± 6.09, 5.00	6.33 ± 6.26, 4.00	7.88 ± 7.92, 6.00	7.17 ± 6.89, 5.00	5.75 ± 4.53, 4.00	4.00 ± 4.03, 2.00
SDI	1.86 ± 1.99, 1.00	1.98 ± 1.96, 1.00	2.76 ± 2.61, 2.00	1.90 ± 1.82, 1.00	1.61 ± 1.83, 1.00	1.72 ± 1.60, 1.00^{^*}
Physical function	51.23 ± 27.19, 50.00	55.79 ± 29.61, 55.00	46.47 ± 25.24, 47.50	48.67 ± 27.24, 50.00	59.18 ± 28.49, 55.00	61.00 ± 32.08, 70.00^{^*}
Role physical	34.09 ± 39.31, 25.00	38.61 ± 41.16, 25.00	38.97 ± 45.31, 0.00	29.11 ± 35.90, 0.00	40.07 ± 41.19, 25.00	44.00 ± 41.63, 50.00
Bodily pain	48.81 ± 25.14, 41.00	56.86 ± 27.00, 52.00^{^*}	54.71 ± 25.59, 51.00	47.13 ± 26.72, 41.00	53.88 ± 26.00, 51.00	63.84 ± 23.63, 62.00^{^*}
General health	39.85 ± 20.50, 37.00	43.21 ± 19.48, 42.00	38.00 ± 19.88, 35.00	38.71 ± 19.68, 37.00	43.68 ± 19.48, 42.00	48.36 ± 21.63, 52.00
Vitality	47.09 ± 20.70, 50.00	45.54 ± 22.62, 45.00	51.47 ± 21.12, 50.00	45.19 ± 21.48, 45.00	45.00 ± 22.90, 45.00	47.00 ± 18.71, 50.00
Social function	59.20 ± 25.55, 50.00	59.90 ± 27.06, 62.50	59.93 ± 26.61, 62.50	57.28 ± 25.76, 62.50	59.76 ± 25.79, 62.50	65.50 ± 28.93, 75.00
Role emotional	53.33 ± 45.42, 66.67	59.74 ± 44.05, 66.67	55.88 ± 44.74, 66.67	53.16 ± 45.45, 66.67	57.99 ± 45.14, 66.67	62.67 ± 43.38, 100.00
Mental health	67.13 ± 19.89, 68.00	68.24 ± 20.02, 72.00	63.88 ± 24.43, 70.00	69.27 ± 18.22, 72.00	66.41 ± 19.76, 68.00	71.36 ± 18.71, 80.00
Physical component scale	33.80 ± 10.41, 33.20	36.08 ± 10.81, 35.90	34.30 ± 10.34, 33.68	32.17 ± 10.44, 31.02	36.84 ± 10.70, 37.85	38.63 ± 9.71, 40.97^**
Mental component scale	52.02 ± 8.12, 51.75	51.92 ± 8.79, 53.69	51.95 ± 9.02, 52.50	53.11 ± 8.41, 52.73	50.88 ± 7.82, 51.32	51.59 ± 9.41, 53.70

↵* p < 0.05,
↵** p < 0.01. Z-AHI: zip code-based annual household income; SLEDAI: Systemic Lupus Erythematosus Disease Activity Index; SDI: American College of Rheumatology Damage Index.