Clinical and sociodemographic data of the patient groups and reference data from the national database (NDB).
| Control Group, n = 178 | Patients with RA, n = 270 | Patients with SLE, n = 247 | NDB* RA, n = 2788 | NDB* SLE, n = 612 | |
|---|---|---|---|---|---|
| Female (%) | 89.8 | 85.2 | 95.5 | 74.2 | 89.5 |
| Age, yrs, mean ± SD | 43.2 ± 9.9 | 47.7 ± 10.0 | 40.0 ± 9.4 | 48.2 ± 9.1 | 39.5 ± 9.8 |
| Disease duration, yrs, mean ± SD | — | 8.8 ± 7.9 | 10.5 ± 7.4 | 6.6 ± 7.4 | 9.5 ± 7.6 |
| No. comorbidities, median (IQR) | 0 (0–1)# | 2 (1–4)# | 2 (1–4)# | 1 (0–2)+ | 1 (0–2)+ |
| HAQ (mean ± SD) | 0.42 ± 0.15 | 1.12 ± 0.53 | 0.78 ± 0.44 | 0.85 ± 0.49 | 0.61 ± 0.38 |
| BMI, kg/m2, mean ± SD | 25.2 ± 4.8 | 25.7 ± 5.2 | 24.9 ± 4.6 | 25.7 ± 4.9 | 24.2 ± 4.7 |
| Participation online (%) | 23.6 | 25.6 | 46.6 | — | — |
| Marital status (%) | |||||
| Single/widowed/living alone | 26.3 | 31.8 | 33.1 | 24.5 | 27.5 |
| Married or in marriage-like relationship | 73.7 | 68.2 | 66.9 | 76.5 | 72.5 |
| Highest professional education (%) | |||||
| No professional education | 4.1 | 7.9 | 9.4 | 12.8 | 10.3 |
| Nonacademic training | 66.7 | 70.3 | 65.8 | 63.9 | 61.6 |
| Academic training | 29.2 | 21.8 | 24.8 | 23.3 | 28.1 |
| Current working and employment situation (%) | |||||
| Full-time | 65.2 | 57.0 | 58.3 | 66.4 | 62.7 |
| Employee | 83.7 | 85.9 | 81.8 | 83.6 | 88.1 |
| White-collar worker | 92.1 | 84.8§ | 91.9§ | 78.6 | 86.3 |
| Pain score last 7 days, (0–10), median (IQR) | 0 (0–1) | 4 (3–7) | 3 (2–5) | 4 (2–6) | 2 (0–5) |
| Impairment score last 7 days, (0–10), median (IQR) | 0 (0–1) | 4 (2–6) | 3 (1–5) | n.a. | n.a. |
↵* Data from the NDB of the German Collaborative Arthritis Centres at the German Rheumatism Research Center in Berlin, reference years 2006–2009, including only employed patients below retirement age13.
↵# Self-reported comorbidities were assessed in multiple choice, pre-given categories only: myocardial infarction, apoplexy, arterial hypertension, diabetes, malignancies, chronic kidney disease, chronic lung disease, chronic liver disease, chronic gastrointestinal diseases, osteoporosis, depression/psychiatric diseases, fibromyalgia, venous thrombosis, degenerative joint disease, elevated blood lipids, cicatrizing skin changes.
↵+ Physician-derived comorbidities also assessed in prespecified categories only, from Albrecht, et al14.
↵§ Chi-square test comparing RA, respectively. SLE patients with the corresponding NDB cohorts, p < 0.05. n.a.: not available; RA: rheumatoid arthritis; SLE: systemic lupus erythematosus; IQR: interquartile range; HAQ: Health Assessment Questionnaire; BMI: body mass index.