Table 3.
Factors associated with progression to inflammatory arthritis since screened aAb+ visit (n=131)
| Characteristic* | Incident IA: No N=111 |
Incident IA: Yes N=20 |
HR (95% CI) | p-value |
|---|---|---|---|---|
| Age: years | 0.98 (0.95-1.01) | 0.24 | ||
| Sex: Female | 87 (73.4%) | 15 (75.0%) | 0.69 (0.25-1.90) | 0.47 |
| Race: NHW | 91 (82.0%) | 13 (65.0%) | 0.39 (0.16-0.98) | 0.04 |
| Shared Epitope: Present | 58 (52.3%) | 13 (65.0%) | 1.24 (0.49-3.14) | 0.65 |
| BMI: ≥25 | 60 (54.1%) | 11 (55.0%) | 1.31 (0.54-3.17) | 0.56 |
| Cigarette Pack-years > 10: Yes | 17 (15.3%) | 1 (5.0%) | 0.32 (0.04-2.43) | 0.27 |
| Tender joint on exam: Yes | 26 (23.4%) | 8 (40.0%) | 2.05 (0.79-5.35) | 0.14 |
| †Self-report joint symptoms: Yes | 67 (60.9%) | 15 (79.0%) | 1.76 (0.58-5.34) | 0.32 |
| ‡CRP: elevated | 38 (34.2%) | 7 (36.8%) | 1.05 (0.41-2.67) | 0.92 |
| Type of aAb+ | ||||
| Anti-CCP- and RF isotype+ | 54 (48.7%) | 6 (30.0%) | ref | ref |
| Anti-CCP+ and RF isotype− | 49 (44.1%) | 11 (55.0%) | 1.67 (0.62-4.52) | 0.31 |
| Anti-CCP+ and RF isotype+ | 8 (7.2%) | 3 (15.0%) | 3.69 (0.92-14.83) | 0.07 |
| RF+ isotype (IgM and/or IgA) ≥ 2x cut-off: Yes | 29 (26.1%) | 6 (30.0%) | 1.69 (0.64-4.48) | 0.29 |
| Anti-CCP+ ≥ 2x cut-off: Yes | 24 (21.6%) | 12 (60.0%) | 4.09 (1.67-10.04) | 0.002 |
| §Anti-CCP+ ≥ optimal cut-off: Yes | 30 (27.0%) | 13 (65.0%) | 3.95 (1.57-9.91) | 0.003 |
| ∣aAb+ Persistence: Yes | 42 (37.8%) | 4 (23.5%) | 1.92 (0.63-5.91) | 0.25 |
| ∣Anti-CCP Persistence: Yes | 37 (33.3%) | 9 (52.9%) | 1.95 (0.75-5.05) | 0.17 |
| Individual aAb+ | ||||
| Anti-CCP2: % positive standard cut-off | 8 (7.2%) | 9 (47.4%) | 11.51 (4.39-30.18) | <0.001 |
| Anti-CCP2: % ≥ 2x standard cut-off | 6 (5.4%) | 8 (40.0%) | 8.88 (3.48-22.64) | <0.001 |
| Anti-CCP2: % positive optimal cut-off (same as standard cut-off) | 11.51 (4.39-30.18) | <0.001 | ||
| Anti-CCP3.1: % positive standard cut-off | 54 (49.1%) | 13 (65.0%) | 1.61 (0.64-4.04) | 0.31 |
| Anti-CCP3.1: % ≥ 2x standard cut-off | 21 (18.9%) | 10 (50.0%) | 3.04 (1.26-7.33) | 0.01 |
| Anti-CCP3.1: % ≥ optimal cut-off | 27 (24.6%) | 11 (55.0%) | 2.84 (1.17-6.86) | 0.02 |
| RF IgM: % positive standard cut-off | 46 (41.4%) | 8 (40.0%) | 1.00 (0.41-2.44) | 0.99 |
| RF IgM: % ≥ 2x standard cut-off | 22 (19.8%) | 6 (30.0%) | 2.34 (0.88-6.21) | 0.09 |
| RF IgA: % positive standard cut-off | 22 (19.8%) | 2 (10.0%) | 0.57 (0.13-2.45) | 0.45 |
| RF IgA: % ≥ 2x standard cut-off | 7 (6.3%) | 1 (5.0%) | 1.05 (0.14-7.86) | 0.97 |
*
Separate unadjusted models for each risk factor were run
†
2 subjects did not complete self-reported joint symptom questionnaire
‡
1 subject missing CRP
§
The optimal cut-off was calculated as ≥5 U/mL for anti-CCP2, and ≥30 U/mL for anti-CCP3.1
∣
3 subjects removed from the analysis of aAb+ persistence because they developed IA prior to the follow-up visit at which aAb+ persistence would have been assessed