Baseline characteristics of patients
| Total | Non-CD | CD | Absolute standardised differences (%) | |
| N=301 | n=195 (64.8%) | n=106 (35.2%) | ||
| Sex, n (%) | ||||
| Female | 268 (89.0) | 178 (91.3) | 90 (84.9) | 19.8 |
| Male | 33 (11.0) | 17 (8.7) | 16 (15.1) | |
| Age at enrolment, n (%) | ||||
| 18–29 | 54 (20.3) | 35 (19.3) | 19 (22.4) | 7.4 |
| 30–39 | 79 (29.7) | 58 (32.0) | 21 (24.7) | 16.3 |
| 40–49 | 59 (22.2) | 40 (22.1) | 19 (22.4) | 0.6 |
| 50–59 | 51 (19.2) | 28 (15.5) | 23 (27.1) | 28.6 |
| 60–65 | 23 (8.7) | 20 (11.1) | 3 (3.5) | 29.2 |
| Age at SLE diagnosis | ||||
| Mean±SD | 27.0±10.5 | 26.3±10.3 | 28.3±10.8 | 18.6 |
| Median (IQR) | 25.1 (18.9–33.2) | 23.6 (18.8–32.4) | 28.3 (19–34.9) | |
| Disease duration at enrolment | ||||
| Mean±SD | 14.0±10.1 | 14.7±10.3 | 12.7±9.40 | 20.2 |
| Median (IQR) | 12.4 (6–21.6) | 12.9 (6.5–22.2) | 11.7 (4.1–19.8) | |
| SLEDAI-2KG score | ||||
| Mean±SD | 4.4±4.7 | 4.0±4.2 | 5.0±5.5 | 20.3 |
| Median (IQR) | 3.0 (0.9–6.2) | 3.0 (1.0–6.0) | 4.0 (0–6.9) | |
| SDI | ||||
| Mean±SD | 1.0±1.5 | 0.9±1.4 | 1.2±1.6 | 19.4 |
| Median (IQR) | 0 (0–2.0) | 0 (0–1.0) | 1.0 (0–2.0) | |
| Presence of anxiety or depression, n (%) | 98 (40.5) | 59 (37.1) | 39 (47.0) | 20.1 |
| Socioeconomic status (in quintiles), n (%) | ||||
| Lowest | 64 (21.3) | 36 (18.5) | 28 (26.4) | 12.9 |
| Medium-low | 61 (20.3) | 38 (19.5) | 23 (21.7) | 5.6 |
| Middle | 74 (24.6) | 51 (26.2) | 23 (21.7) | 10.0 |
| Medium-high | 48 (16.0) | 30 (15.4) | 18 (17.0) | 1.6 |
| Highest | 52 (17.3) | 38 (19.5) | 14 (13.2) | 7.5 |
| Ethnicity, n (%) | ||||
| Black | 59 (19.6) | 23 (11.8) | 36 (34.0) | 54.7 |
| White | 163 (54.2) | 119 (61.0) | 44 (41.5) | 39.8 |
| Chinese | 33 (11.0) | 23 (11.8) | 10 (9.4) | 7.7 |
| Others | 46 (15.3) | 30 (15.4) | 16 (15.1) | 0.8 |
| Education level, n (%) | ||||
| Below grade 8 | 0 | 0 | 0 | |
| Grade 8 | 11 (3.7) | 8 (4.1) | 3 (2.9) | 6.6 |
| High school graduate | 50 (16.8) | 28 (14.4) | 22 (21.4) | 18.1 |
| College | 113 (38.1) | 71 (36.6) | 42 (40.8) | 8.6 |
| University | 123 (41.4) | 87 (44.9) | 36 (35.0) | 20.3 |
| Employment status, n (%) | ||||
| Employed | 167 (55.5) | 115 (59.0) | 52 (49.1) | 20 |
| Retired | 5 (1.7) | 3 (1.5) | 2 (1.9) | 2.7 |
| Home maker | 17 (5.7) | 12 (6.2) | 5 (4.7) | 6.3 |
| Student | 29 (9.6) | 20 (10.3) | 9 (8.5) | 6.1 |
| Disabled | 55 (18.3) | 30 (15.4) | 25 (23.6) | 20.8 |
| Sick leave | 12 (4.0) | 7 (3.6) | 5 (4.7) | 5.7 |
| Looking for work | 8 (2.7) | 4 (2.1) | 4 (3.8) | 10.3 |
| Other | 8 (2.7) | 4 (2.1) | 4 (3.8) | 10.3 |
| Marital status, n (%) | ||||
| Single | 155 (51.7) | 98 (50.3) | 57 (54.3) | 8.1 |
| Married | 104 (34.7) | 78 (40.0) | 26 (24.8) | 33 |
| Widowed | 3 (1.0) | 2 (1.0) | 1 (1.0) | 0.7 |
| Divorced | 17 (5.7) | 8 (4.1) | 9 (8.6) | 18.4 |
| Separated | 7 (2.3) | 4 (2.1) | 3 (2.9) | 5.2 |
| Common law | 14 (4.7) | 5 (2.6) | 9 (8.6) | 26.4 |
Cognitive status was defined as follows: non-CD: z-score of ≤−1.5 in ≤1 domain and CD: z-score of ≤−1.5 in ≥2 domains of the ACR-NB.
ACR-NB, American College of Rheumatology neuropsychological battery; CD, cognitive dysfunction; SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SLEDAI-2KG, SLE Disease Activity Index 2000 Glucocorticoid Index.