Characteristics of patients with incident RA in the 1985–1994 cohort (Rochester, Minnesota residents) and 1995–2007 cohort (Olmsted County, containing Rochester, Minnesota, residents).
| Variable | Period of RA Incidence | p | |
|---|---|---|---|
| 1985–1994 (n = 147) | 1995–2007 (n = 463) | ||
| Age, mean ± SD, yrs | 57.8 ± 16.4 | 55.6 ± 15.6 | 0.14 |
| Female, n (%) | 101 (69) | 320 (69) | 0.93 |
| RF-positive, ever, n (%) | 108 (73) | 306 (67) | 0.12 |
| % tested for RF, ever | 100 | 99 | |
| ANA-positive, ever, n (%) | 77 (60) | 105 (26) | < 0.001 |
| % tested for ANA, ever | 88 | 86 | |
| Highest ESR in the 1st year after RA incidence, mean ± SD mm/h | 35.3 ± 25.1 | 30.0 ± 24.7 | 0.007 |
| ESR ≥ 3 values ≥ 60 mm/h, n (%) | 23 (16) | 28 (6) | < 0.001 |
| Joint erosions/destructive changes, n (%) | |||
| Ever | 66 (45) | 229 (49) | 0.33 |
| In 1st year after RA incidence | 31 (21) | 134 (29) | 0.06 |
| % radiographed, ever | 89 | 97 | |
| Cigarette smoking, n (%) | |||
| Ever | 88 (60) | 233 (50) | 0.04 |
| Current | 27 (18) | 80 (17) | 0.76 |
| Obesity (BMI ≥ 30 kg/m2), n (%) | |||
| Ever | 37 (25) | 237 (51) | < 0.001 |
| In 1st year after RA incidence | 32 (22) | 218 (47) | < 0.001 |
| Drug exposure, ever, n (%) | |||
| Methotrexate | 75 (51) | 299 (65) | 0.003 |
| Hydroxychloroquine | 72 (49) | 295 (65) | 0.002 |
| Other DMARD | 67 (46) | 104 (23) | < 0.001 |
| Biologic response modifiers | 3 (2) | 96 (21) | < 0.001 |
| Corticosteroids | 109 (74) | 376 (81) | 0.06 |
RA: rheumatoid arthritis; RF: rheumatoid factor; ANA: antinuclear antibody; ESR: erythrocyte sedimentation rate; BMI: body mass index; DMARD: disease-modifying antirheumatic drugs.