Table 1.
Baseline sociodemographic and clinical characteristics
| Variables | Initiated first biologic† | Initiated TNF-inhibitor as first biologic† | Initiated non- TNF-inhibitor as first biologic† | Initiated second biologic‡ | Initiated TNF-inhibitor as second biologic‡ | Initiated non-TNF-inhibitor as second biologic‡ |
|---|---|---|---|---|---|---|
| N | 2281 | 2225 | 56 | 1097 | 988 | 109 |
| Started biologic ≥2005 (%) | 524 (23) | 470 (21)** | 54 (96)** | 520 (47) | 414 (42)** | 106 (97)** |
| Age (years) | 59.7 [12.4] | 59.6 [12.4]** | 65.3 [11.1]** | 60.8 [12.2] | 60.5 [12.0]* | 63.0 [13.7]* |
| Gender (% female) | 1830 (80) | 1784 (80) | 46 (82) | 871 (79) | 784 (79) | 87 (80) |
| Disease duration (years) | 15.0 [11.0] | 14.9 [11.0] | 16.4 [11.3] | 16.2 [11.3] | 16.0 [11.4] | 18.1 [11.0] |
| Ethnicity (% Caucasian) | 2090 (93) | 2051 (93)** | 39 (74)** | 975 (91) | 879 (91) | 96 (93) |
| Body mass index (kg/m2) | 27.5 [6.6] | 27.4 [6.6] | 28.8 [6.5] | 28.1 [6.3] | 28.1 [6.3] | 27.8 [5.6] |
| Married (%) | 1626 (71) | 1593 (72)* | 33 (59)* | 786 (72) | 709 (72) | 77 (71) |
| Educational level (years) | 13.8 [2.3] | 13.8 [2.3] | 14.2 [2.1] | 13.6 [2.2] | 13.6 [2.2] | 13.9 [2.1] |
| Employed (%) | 775 (34) | 760 (34) | 15 (27) | 337 (31) | 314 (32)* | 23 (21)* |
| Total income ($10 000) | 4.8 [3.0] | 4.9 [3.0] | 4.4 [3.1] | 4.8 [3.0] | 4.8 [3.0] | 4.7 [2.8] |
| Smoking (%) | 286 (13) | 283 (13) | 3 (5) | 126 (11) | 118 (12) | 53 (10) |
| Comorbidity index (0–9) | 1.5 [1.4] | 1.5 [1.4] | 1.8 [1.3] | 1.8 [1.6] | 1.7 [1.5]* | 2.1 [1.6]* |
| HAQ (0–3) | 1.2 [0.7] | 1.2 [0.7] | 1.1 [0.7] | 1.2 [0.7] | 1.2 [0.7] | 1.3 [0.8] |
| Pain scale (0–10) | 4.5 [2.8] | 4.5 [2.8] | 4.6 [2.9] | 4.4 [2.8] | 4.4 [2.8] | 4.6 [2.9] |
| Global severity (0–10) | 4.0 [2.4] | 4.0 [2.4] | 4.3 [2.4] | 4.2 [2.4] | 4.1 [2.4] | 4.6 [2.4] |
| Fatigue (0–10) | 4.8 [2.9] | 4.8 [2.9] | 4.8 [3.3] | 4.8 [2.9] | 4.8 [2.9] | 5.1 [2.8] |
| Sleep scale (0–10) | 4.0 [3.0] | 4.0 [3.0] | 3.7 [2.9] | 4.1 [3.0] | 4.2 [3.1] | 4.0 [2.9] |
| RADAI | 3.2 [1.6] | 3.2 [1.6] | 3.1 [1.8] | 3.1 [1.7] | 3.1 [1.7] | 3.1 [1.6] |
| SF-36 PCS (0–100) | 34.0 [10.5] | 34.0 [10.5] | 35.9 [10.6] | 33.9 [10.7] | 33.9 [10.8] | 33.1 [9.9] |
| SF-36 MCS (0–100) | 49.3 [11.1] | 49.3 [11.1] | 48.4 [12.6] | 48.6 [11.3] | 48.6 [11.1] | 48.2 [12.4] |
| Polysymptomatic distress (0–31) | 11.6 [7.2] | 11.7 [7.2] | 11.1 [7.4] | 11.9 [7.5] | 11.8 [7.5] | 13.0 [7.5] |
| Number of DMARDs | 3.0 [1.6] | 3.0 [1.6]* | 2.5 [1.4]* | 3.1 [1.7] | 3.1 [1.7] | 2.9 [1.7] |
| Concomitant DMARD (%) | 2084 (91) | 2035 (91) | 49 (88) | 883 (80) | 797 (81) | 86 (79) |
| Methotrexate (%) | 1567 (69) | 1534 (69) | 33 (59) | 661 (60) | 596 (60) | 65 (60) |
| Methotrexate duration (months) | 48.8 [54.7] | 48.8 [54.5] | 48.9 [60.4] | 58.4 [58.9] | 56.3 [56.8]* | 77.4 [72.8]* |
| Leflunomide (%) | 532 (23) | 516 (23) | 16 (29) | 185 (17) | 171 (17) | 14 (13) |
| Prednisone (%) | 1073 (47) | 1053 (47) | 20 (36) | 482 (44) | 433 (44) | 49 (45) |
| NSAIDs (%) | 1599 (70) | 1574 (71)** | 25 (45)** | 659 (60) | 600 (61) | 59 (54) |
| Biologic started (%) | ||||||
| Etanercept | 1018 (45) | 315 (29) | ||||
| Infliximab | 873 (38) | 427 (39) | ||||
| Adalimumab | 310 (14) | 218 (20) | ||||
| Golimumab | 8 (0.4) | 11 (1.0) | ||||
| Certolizumab pegol | 16 (0.7) | 17 (1.5) | ||||
| Abatacept | 28 (1.2) | 61 (6) | ||||
| Rituximab | 25 (1.1) | 42 (4) | ||||
| Tocilizumab | 3 (0.1) | 6 (0.5) |
Results are expressed in mean [SD] or n (%). Percentages refer to the total number of patients with information available on a specific variable, which might not match with dividing the n over the total group N due to eventual missing items
*p Value <0.05; **p value<0.001.
†Information corresponding to the observation when the first biologic was started.
‡Information corresponding to the observation when the second biologic was started.
DMARDs, disease-modifying antirheumatic drugs; HAQ, Health Assessment Questionnaire; NSAIDs, non-steroidal anti-inflammatory drugs; RADAI, rheumatoid arthritis disease activity index; SF-36 MCS and PCS, Short form-36, mental component summary and physical component summary.