Table 2.

DAS28 over time with and without confounders with linear mixed models and DAS28 baseline as covariate.

β95% CIp
Model without confounder correction
Intercept1.5381.294–1.781< 0.001
TNFi mono (ref)
  TNFi + SSZ−0.375−0.601 to −0.1490.001
  TNFi + LEF−0.043−0.290 to 0.2040.731
  TNFi + other csDMARD−0.372−0.605 to −0.1380.002
  TNFi + MTX−0.510−0.606 to −0.343< 0.001
Time−0.029−0.039 to −0.019< 0.001
DAS28 at baseline0.5030.464–0.543< 0.001
Model with confounder correction
Intercept< 0.001
TNFi mono (ref)
  TNFi + SSZ−0.420−0.696 to −0.1440.003
  TNFi + LEF−0.275−0.584 to 0.0330.080
  TNFi + other csDMARD−0.502−0.806 to −0.1980.001
  TNFi + MTX−0.572−0.734 to −0.411< 0.001
Time−0.032−0.041 to −0.022< 0.001
DAS28 at baseline0.4150.359–0.471< 0.001
Erosive disease negative0.2170.071–0.3620.004
HAQ baseline0.1920.074–0.3090.001
Age0.0160.011–0.021< 0.001
Disease duration−0.009−0.017 to −0.0000.041
Medication: Infliximab (ref)
  Adalimumab−0.678−0.869 to −0.488< 0.001
  Etanercept−0.704−0.891 to −0.517< 0.001
Male sex−0.069−0.206 to 0.0680.326
RF-negative0.103−0.042 to 0.2490.164
No. previous DMARD > 4 (ref)
  1−0.048−0.336 to 0.2390.741
  2−0.008−0.238 to 0.2210.944
  30.136−0.088 to 0.3610.234
  40.079−0.162 to 0.3200.518
Year of starting TNFi0.7340.678 to 0.795< 0.001
  • Data are missing for 53.7% of the patients. Patients with missing DAS28 values are equally divided among the groups TNFi monotherapy, TNFi + LEF, TNFi + SSZ, TNFi + MTX, TNFi + other csDMARD, TNFi + MTX + other csDMARD (p value = 0.365). The missing data per measurement timepoints are equally divided among the groups. TNFi: tumor necrosis factor inhibitor; MTX: methotrexate; SSZ: sulfasalazine; LEF: leflunomide; csDMARD: conventional synthetic disease-modifying antirheumatic drugs; ref: reference; HAQ: Health Assessment Questionnaire; DAS28: 28-joint Disease Activity Score; RF: rheumatoid factor.