Characteristics of the register-identified prevalent and incident patients with RA
| Variable | Prevalent RA | Incident RA | |
|---|---|---|---|
| Overall | Treated with biologics* | Overall | |
| n | 49 829 | 9139 | 2695 |
| Women, n (%) | 36 325 (73) | 6896 (75) | 1847 (69) |
| Age | |||
| Mean (SD) | 65.1 (14.3) | 58.4 (12.9) | 61.9 (15.7) |
| Median (25th–75th; min–max) | 66.1 (57–76; 18–100) | 60.2 (50–67; 20–93) | 64.0 (53–74; 18–97) |
| Age 18–64 years, n (%) | 21 551 (43) | 5835 (64) | 1353 (50) |
| Age ≥65 years, n (%) | 28 278 (57) | 3304 (36) | 1342 (50) |
| Rheumatoid factor positive†, n (%) | 34 728 (70) | 7468 (82) | 1531 (57) |
| Level of education, n (%) | |||
| ≤9 years | 18 178 (36) | 2361 (26) | 952 (35) |
| 10–12 years | 20 891 (42) | 4085 (45) | 1145 (42) |
| >12 years | 10 545 (21) | 2668 (29) | 577 (21) |
| Missing | 215 (0) | 25 (0) | 21 (1) |
| Time since register identification (years)‡ | |||
| Mean (SD) | 9.7 (8.2) | 10.4 (7.6) | – |
| Median (25th–75th; min–max) | 7.7 (4–12; 0–40) | 8.6 (5–13; 0–40) | – |
| Mortality during follow-up | |||
| n deaths, (%) | 1847 (3.7) | 87 (1.0) | 72 (2.7) |
*Patients with RA, with any dispensed non-infusion biologics in 2009, or with an ongoing treatment of infusion biologics on 1 January 2010.
†Rheumatoid factor status was collected from the Swedish Rheumatology Quality register. Patients with missing rheumatoid factor status were defined with an algorithm using ICD10-codes.
‡Possible truncation of time since the outpatient part of the patient register started in 2001, resulting in that a large proportion of the patients with RA were identified in 2001 (15%) and a possible underestimation of the true time since disease onset.
RA, rheumatoid arthritis.