Table 1.
Characteristics of the RA study population in CPRD and in CPRD-HES
| Characteristic | CPRD (n=11 582) |
CPRD-HES (n=7221) |
|---|---|---|
| Median follow-up, years (IQR) | 9.0 (4.7–10) | 9.0 (5.3–10) |
| Sex, n (%) | ||
| Male | 3729 (32.2) | 2263 (31.3) |
| Female | 7853 (67.8) | 4958 (68.7) |
| Age, years, mean (±SD) | 62.9 (11.4) | 63.0 (11.5) |
| Body mass index, kg/m2, mean (±SD) | 26.8 (5.3) | 26.7 (5.3) |
| Missing | 1780 (15.4) | 1086 (15.0) |
| Current smoking, n (%) | 4147 (35.8) | 2573 (35.6) |
| Missing, n (%) | 890 (7.7) | 547 (7.6) |
| Alcohol use ≥3 units per day, n (%) | 580 (5.0) | 371 (5.1) |
| Missing, n (%) | 1759 (15.2) | 1081 (15.0) |
| Previous fracture, n (%) | 1908 (16.5) | 1184 (16.4) |
| Glucocorticoid use yes/no*, n (%) | 1806 (15.6) | 1176 (16.3) |
| Glucocorticoid use, daily dose†, mean (±SD) | 4.9 (3.2) | 4.9 (3.2) |
| 0<GC<2.5 mg/day, n (%) | 508 (4.4) | 295 (4.1) |
| 2.5≤GC≤7.5 mg/day, n (%) | 1160 (10.0) | 786 (10.9) |
| >7.5 mg/day, n (%) | 305 (2.6) | 200 (2.8) |
| Secondary osteoporosis, n (%) | 580 (5.0) | 372 (5.2) |
| Age of RA onset, years, mean (±SD) | 52.8 (13.5) | 52.8 (13.7) |
| RA disease duration, years, mean (±SD) | 10.1 (9.2) | 10.2 (9.3) |
| <2 years since diagnosis | 1336 (11.5) | 824 (11.4) |
| 2–10 years since diagnosis | 5900 (50.9) | 3671 (50.8) |
| >10 years since diagnosis | 4346 (37.5) | 2726 (37.8) |
*Glucocorticoid use was defined as in FRAX: prescription within 90 days before or ≥two prescriptions with a mean daily dose of prednisolone (or equivalents) of ≥5 mg in the year before.
†Glucocorticoid use was defined as ≥two prescriptions with a mean daily dose of prednisolone (or equivalents) of <2.5, 2.5–7.5 or >7.5 mg/day in the year before.CPRD, Clinical Practice Research Datalink; GC, oral glucocorticoids; HES, Hospital Episode Statistics; RA, rheumatoid arthritis.