Demographics, characteristics, and healthcare use in sample of veterans at risk for axSpA.
| Variables | Yes axSpA, n = 162 | No axSpA, n = 438 | ||||||
|---|---|---|---|---|---|---|---|---|
| N or Mean | SD or % | 95% CI | N or Mean | SD or % | 95% CI | |||
| Demographics | ||||||||
| Age at cohort entry, yrs | 56.2 | 13.5 | 54.1 | 58.3 | 59.8 | 13.3 | 58.6 | 61.1 |
| Sex, male | 155 | 95.7 | 91.4 | 97.9 | 391 | 89.3 | 86.0 | 91.8 |
| Race | ||||||||
| White | 128 | 79.0 | 72.1 | 84.6 | 327 | 74.7 | 70.4 | 78.5 |
| Black | 18 | 11.1 | 7.1 | 16.9 | 67 | 15.3 | 12.2 | 19.0 |
| Other | 2 | 1.2 | 0.3 | 4.4 | 6 | 1.4 | 0.6 | 3.0 |
| Unknown | 14 | 8.6 | 5.2 | 14.0 | 38 | 8.7 | 6.4 | 11.7 |
| Ethnicity | ||||||||
| Non-Hispanic | 144 | 88.9 | 83.1 | 92.9 | 394 | 90.0 | 86.8 | 92.4 |
| Hispanic | 7 | 4.3 | 2.1 | 8.7 | 21 | 4.8 | 3.2 | 7.2 |
| Unknown | 11 | 6.8 | 3.8 | 11.8 | 23 | 5.3 | 3.5 | 7.8 |
| Geographic region at cohort entry | ||||||||
| Southeast | 57 | 35.2 | 28.3 | 42.8 | 167 | 38.1 | 33.7 | 42.8 |
| North Atlantic | 35 | 21.6 | 16.0 | 28.6 | 91 | 20.8 | 17.2 | 24.8 |
| Midwest | 30 | 18.5 | 13.3 | 25.2 | 70 | 16.0 | 12.9 | 19.7 |
| Continental | 22 | 13.6 | 9.1 | 19.7 | 62 | 14.2 | 11.2 | 17.7 |
| Pacific | 18 | 11.1 | 7.1 | 16.9 | 48 | 11.0 | 8.4 | 14.2 |
| Laboratory tests | ||||||||
| C-reactive protein, mean (mg/l) | 19.4 | 29.4 | 14.2 | 24.5 | 18.3 | 39.3 | 12.7 | 24.0 |
| ESR, mean, mm/h | 25.3 | 26.1 | 20.9 | 29.7 | 22.1 | 23.9 | 19.2 | 25.0 |
| RF tested | 65 | 40.1 | 32.9 | 47.8 | 162 | 37.0 | 32.6 | 41.6 |
| RF-positive, among tested patients | 9 | 13.9 | 7.5 | 24.3 | 28 | 17.3 | 12.2 | 23.9 |
| CCP tested | 33 | 20.4 | 14.9 | 27.2 | 68 | 15.5 | 12.4 | 19.2 |
| CCP-positive, among tested patients | 0 | 0.0 | 0.0 | 0.0 | 12 | 17.7 | 10.4 | 28.4 |
| HLA-B27 tested | 72 | 44.4 | 37.0 | 52.1 | 81 | 18.5 | 15.1 | 22.4 |
| HLA-B27–positive, among tested patients | 59 | 81.9 | 71.5 | 89.1 | 66 | 81.5 | 71.7 | 88.4 |
| HLA-B27–positive, among tested patients not selected into population for HLA-B27 positivity* | 21 | 61.8 | 45.0 | 76.1 | 4 | 21.1 | 11.8 | 48.8 |
| DMARD | ||||||||
| ≥ 1 biologic during study period | 72 | 44.4 | 37.0 | 52.1 | 40 | 9.1 | 6.8 | 12.2 |
| ≥ 1 nonbiologic during study period | 52 | 32.1 | 25.4 | 39.6 | 81 | 18.5 | 15.1 | 22.4 |
| Healthcare use within the VA | ||||||||
| Active system use duration during study period, yrs | 9.3 | 2.0 | 9.0 | 9.6 | 9.0 | 2.4 | 8.7 | 9.2 |
| No. provider visits/yr during active system use | 43.6 | 39.3 | 37.5 | 49.6 | 44.5 | 42.0 | 40.6 | 48.5 |
↵* The 100 patients who were selected into the study population specifically because of a positive HLA-B27 test were excluded. RF: rheumatoid factor; CCP: cyclic citrullinated peptide antibody; DMARD: disease-modifying antirheumatic drugs; ESR: erythrocyte sedimentation rate; axSpA: axial spondyloarthritis; VA: (US) Veterans Affairs.