Baseline predictors of non-remission at 24 months in the SWEFOT trial population with available BMI, ORs and 95% CIs
| Parameters | Univariate (n=215)* | Univariate (n=154)† | Multivariate (n=154)† |
| Obesity | 4.1 (1.8–9.1) | 5.4 (1.9–15.2) | 5.2 (1.8–15.2) |
| Female sex | 2.5 (1.4–4.6) | 2.4 (1.1–4.9) | 2.6 (1.1–5.8) |
| Current smokers | 1.8 (0.9–4.0) | 1.9 (0.9–4.0) | 2.6 (1.1–6.3) |
| HAQ | 2.0 (1.2–3.2) | 1.9 (1.1–3.2) | 1.9 (1.1–3.4) |
| Age, years | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) |
| DAS28 | 1.7 (1.3–2.3) | 1.9 (1.3–2.7) | 1.9 (1.3–2.9)‡ |
| Tender joints | 1.1 (1.0–1.1) | 1.1 (1.0–1.2) | 1.1 (1.0–1.2)‡ |
| Prednisolone | 1.3 (0.6–3.0) | 1.4 (0.5–3.8) | – |
| Symptom duration | 1.0 (1.0–1.1) | 1.0 (0.9–1.1) | – |
| Erosions | 0.8 (0.5–1.5) | 0.9 (0.5–1.9) | – |
| SHS | 1.0 (1.0–1.0) | 1.0 (0.9–1.0) | – |
| Swollen joints | 1.0 (1.0–1.1) | 1.0 (1.0–1.1) | – |
| VAS-global | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | – |
| VAS-pain | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | – |
| ESR | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | – |
| CRP | 1.0 (1.0–1.0) | 1.0 (1.0–1.0) | – |
| ACPA positive | 0.9 (0.5–1.5) | 0.9 (0.4–1.7) | – |
| RF positive | 1.1 (0.6–1.9) | 1.2 (0.6–2.4) | – |
Risk of not achieving clinical remission (DAS28 ≥2.6) after 24 months was calculated using univariate and multivariate binary logistic regression (significant findings are in bold). Obese (BMI ≥30) (*n=39; †n=26) were compared with non-obese patients (BMI <30, *n=176; †n=128). Additional outcomes assessed: female sex; current vs non-current smokers (*n=156); per-unit increase in HAQ (*n=211); per-year increase in age; DAS28; tender joints; concurrent use of prednisolone (*n=212; †n=152); patient-reported symptom duration in months before baseline; presence of erosions and SHS (*n=197; †n=140); swollen joints; VAS-global (*n=214); VAS-pain (*n=214); ESR (*n=214; †n=153); CRP; and ACPA (*n=200; †n=147) or RF positivity (*n=214; †n=153).
†Among patients who had available data for all parameters included in the final multivariate model (highlighted in grey: obesity, sex, smoking status, DAS28, HAQ and age) (n=154), each predictor was also tested by univariate analysis individually.
‡DAS28 and tender joints were not chosen as predictors in the final model due to collinearity. These variables were tested and weighed against their counterparts in a multivariate model (DAS28 or tender joints instead of HAQ). The final model provided the greatest predictive capacity; predicting non-remission with a classification accuracy rate of 67.5% vs a null proportional-by-chance accuracy rate of 50%.
ACPA, anticitrullinated protein antibody; BMI, body mass index; CRP, C reactive protein; DAS28, 28-joint count Disease Activity Score; HAQ, Health Assessment Questionnaire; ESR, erythrocyte sedimentation rate; RF, rheumatoid factor; SHS, Sharp-van der Heijde Score; SWEFOT, Swedish Pharmacotherapy Trial; VAS-global, Visual Analogue Scale for global assessment; VAS-pain, Visual Analogue Scale for pain.