Table 1. Baseline Characteristics.
| All Patients | ACPA+ and/or RF+ Patients | |||||
| Abatacept n=100 | TNFi n=165 | P-Value | Abatacept n=55 | TNFi n=108 | P-Value | |
| TNFi, n (%) | n/a | n/a | ||||
| Adalimumab | - | 67 (40.6) | - | 44 (40.7) | ||
| Etanercept | - | 55 (33.3) | - | 36 (33.3) | ||
| Infliximab | - | 28 (17.0) | - | 20 (18.5) | ||
| Golimumab | - | 11 (6.7) | - | 6 (5.6) | ||
| Certolizumab Pegol | - | 4 (2.4) | - | 2 (1.9) | ||
| Clinic, n (%) | <0.001 | 0.002 | ||||
| 1 | 5 (5.0) | 33 (20.0) | 5 (9.1) | 27 (25.0) | ||
| 2 | 24 (24.0) | 42 (25.5) | 16 (29.1) | 30 (27.8) | ||
| 3 | 45 (45.0) | 22 (13.3) | 16 (29.1) | 12 (11.1) | ||
| 4 | 10 (10.0) | 51 (30.9) | 6 (10.9) | 27 (25.0) | ||
| 5 | 5 (5.0) | 11 (6.7) | 4 (7.3) | 6 (5.6) | ||
| 6 | 11 (11.0) | 6 (3.6) | 8 (14.6) | 6 (5.6) | ||
| Female, n (%) | 82 (82.0) | 121 (73.3) | 0.106 | 46 (83.6) | 78 (72.2) | 0.106 |
| Age in Years (in 2017), Mean (SD) | 67.0 (13.6) | 60.3 (12.2) | <0.001 | 64.5 (12.7) | 59.4 (12.5) | 0.014 |
| CCI, Mean (SD) | 0.7 (1.0) | 0.5 (0.9) | 0.080 | 0.7 (1.1) | 0.5 (0.9) | 0.170 |
| Total Duration of Treatment at Clinic (years), Mean (SD) | 5.7 (4.2) | 5.2 (3.4) | 0.288 | 5.1 (3.7) | 4.8 (3.0) | 0.575 |
| No. Physician Office Visits (1-year pre-index), Mean (SD) | 3.8 (2.4) | 4.0 (3.4) | 0.588 | 3.7 (2.2) | 3.6 (2.3) | 0.760 |
| No. Hospitalizations (1-year pre-index), Mean (SD) | 0.1 (0.4)a | 0.1 (0.3)a | 0.037 | 0.2 (0.4)b | 0.1 (0.4)b | 0.084 |
Abbreviations: ACPA+, positive anti-cyclic citrullinated peptide antibodies; CCI, Charlson comorbidity index; RF+, positive rheumatoid factor antibodies; SD, standard deviation; TNFi, tumor necrosis factor inhibitor.
a Additional detail provided to describe significant differences: abatacept=0.12 (0.35); TNFi=0.06 (0.29).
b Additional detail provided to describe significant differences: abatacept=0.18 (0.43); TNFi=0.10 (0.36).