Patient characteristics at the end of the STRASS trial
| M-arm | S-arm | |||
| STRASS population (n=73) | Extended follow-up population (n=52) | STRASS population (n=64) | Extended follow-up population (n=44) | |
| Age, years | 57.9±12.0 | 64.1±10.8 | 55.8±10.7 | 61.1±11.5 |
| Female sex, n (%) | 54 (74) | 37 (71.1) | 53 (82.8) | 47 (84.1) |
| Disease duration, years | 12.5±10.3 | 18.9±9.5 | 9.8±5.4 | 18.7±8.9 |
| IgM RF positivity, n (%) | 42 (67.7) | 41 (78.8) | 37 (68.5) | 29 (65.9) |
| ACPA positivity, n (%) | 46 (76.7) | 30 (57.7) | 45 (80.4) | 28 (63.6) |
| Erosive disease on X-rays (%) | 64 (87.7) | 44 (84.6) | 57 (89.1) | 40 (90.9) |
| ACR 1987 criteria, n (%) | 73 (100) | 52 (100) | 64 (100) | 44 (100) |
| ACR/EULAR 2010, n (%) | 64 (100)* | 52 (100) | 60 (100)* | 44 (100) |
| Tender joint count (28 joints) | 0.7±2.7 | 1.1±1.7 | 0.9±1.8 | 2.7±5.1 |
| Swollen joint count (28 joints) | 0.2±0.5 | 1.1±2.2 | 0.2±0.6 | 0.8±1.2 |
| ESR, mm/first hour | 15.8±15.6 | 14±11.5 | 16.5±10.9 | 17.7±11.8 |
| CRP, mg/L | 6.8±10.2 | 4.3±6.3 | 4.0±3.4 | 3.2±3.3 |
| DAS28 | 2.2±1.2 | 1.9±0.6 | 2.7±1.1 | 2.6±1.1 |
| Ongoing bDMARD and DMARD treatment | ||||
| ADA, n (%) | 34 (46.6) | 23 (44.2) | 29 (45.3) | 12 (27.3) |
| ETA, n (%) | 39 (53.4) | 28 (53.9) | 35 (54.7) | 19 (43.2) |
| Step 0, n (%) | 73 (100) | 51 (98.1) | 13 (20.3) | 9 (20.4) |
| Step 1, n (%) | 0 (0) | 0 (0) | 6 (9.4) | 6 (13.6) |
| Step 2, n (%) | 0 (0) | 0 (0) | 7 (10.9) | 4 (9.1) |
| Step 3, n (%) | 0 (0) | 0 (0) | 10 (15.6) | 12 (27.3) |
| No bDMARD treatment, n (%) (ie, step 4) | 0 (0) | 0 (0) | 26 (40.6) | 12 (27.3) |
| Other, n (%) | 0 (0) | 1 (1.9) | 1 (2.2) | 1 (2.2) |
| Switch from initial bDMARD during STRASS | 0 (0) | 2 (3.8) | 2 (3.1) | 2 (4.5) |
| Dose quotient of bDMARD intake | 1±0 | 1±0 | 0.38±0.39 | 0.45±0.38 |
| DMARD combination, n (%) | 56 (76.7) | 38 (73.1) | 48 (75.0) | 30 (68.2) |
Data are presented as mean±SD or n (%).
The end of the STRASS trial corresponds to 18 months after randomisation.
*Data available for 64 and 60 patients in the M-arm and S-arm, respectively, for 2010 ACR/EULAR criteria assessment.
ACPA, anticitrullinated peptide antibody; ACR, American College of Rheumatology; ADA, adalimumab; bDMARD, biological disease-modifying antirheumatic drug; CRP, C reactive protein; DAS, Disease Activity Score; Dose quotient, actual total intake over a month/standard full regimen intake over a month; ESR, erythrocyte sedimentation rate; ETA, etanercept; EULAR, European League Against Rheumatism; IgM, immunoglobulin M; M-arm, maintenance arm; RF, rheumatoid factor; S-arm, spacing arm; STRASS, Spacing of TNF-blocker injections in Rheumatoid ArthritiS Study.