Baseline characteristics of the study cohort stratified by previous exposure to anti-TNF and newly prescribed anti-TNF agent
| Biologic naive | First-time switchers* | |||||||
|---|---|---|---|---|---|---|---|---|
| Characteristics | ADA N=460 | ETA N=480 | INF N=535 | p Value† | ADA N=311 | ETA N=139 | INF N=166 | p Value† |
| Demographics | ||||||||
| Women | 78% | 76% | 72% | 0.06 | 82% | 79% | 82% | 0.72 |
| Age (years) | 55±12 | 54±13 | 61±13 | <0.001 | 56±13 | 56±13 | 56±12 | 0.83 |
| Healthcare coverage‡ | ||||||||
| Private insurance | 78% | 81% | 72% | 0.04 | 79% | 81% | 74% | 0.39 |
| Medicare | 27% | 24% | 45% | <0.001 | 34% | 35% | 34% | 0.98 |
| Medicaid | 7% | 9% | 6% | 0.30 | 9% | 6% | 5% | 0.23 |
| Clinical | ||||||||
| Duration of RA (years) | 8.9±9.5 | 8.8±9.2 | 9.6±9.9 | <0.001 | 12.7±9.7 | 10.6±10.0 | 11.8±9.4 | 0.09 |
| Tender joint count | 7.1±7.1 | 6.4±6.2 | 6.3±6.7 | 0.11 | 7.6±7.1 | 6.6±6.8 | 6.3±6.9 | 0.14 |
| Swollen joint count | 7.6±6.5 | 6.5±5.8 | 8.2±6.9 | <0.001 | 6.7±6.3 | 6.9±6.5 | 7.4±7.00 | 0.57 |
| Patient global assessment (0–100 mm) | 41.2±27.5 | 40.1±24.7 | 38.7±24.9 | 0.34 | 44.4±25.3 | 42.9±27.3 | 38.7±25.5 | 0.09 |
| Patient pain assessment (0–100 mm) | 43.3±28.0 | 41.5±24.7 | 41.5±25.8 | 0.48 | 45.7±25.5 | 46.0±26.0 | 41.9±24.9 | 0.26 |
| Physician global assessment (0–100 mm) | 36.9±20.5 | 33.5±20.3 | 34.4±20.9 | 0.03 | 37.3±22.3 | 33.3±20.5 | 32.8±22.2 | 0.05 |
| mHAQ score | 0.5±0.5 | 0.5±0.5 | 0.4±0.5 | 0.11 | 0.6±0.5 | 0.6±0.5 | 0.4±0.4 | 0.01 |
| ESR (mm/h) | 25.7±23.3 | 24.2±19.8 | 28.2±23.2 | 0.19 | 28.9±23.2 | 28.1±23.5 | 28.2±22.0 | 0.96 |
| DAS28 | 4.49±1.6 | 4.48±1.4 | 4.53±1.4 | 0.91 | 4.55±1.5 | 4.39±1.3 | 4.46 ±.6 | 0.79 |
| CDAI | 22.3±13.7 | 20.2±12.3 | 22.0±13.4 | 0.04 | 22.4±14.3 | 21.1±13.4 | 20.6±13.9 | 0.43 |
| Disease activity per CDAI | 0.15 | 0.69 | ||||||
| High (>21) | 21 | 22 | 22 | 23 | 21 | 25 | ||
| Moderate (>5–≤21) | 37 | 41 | 34 | 33 | 39 | 36 | ||
| Low (>2.2–≤5) | 42 | 37 | 44 | 44 | 40 | 39 | ||
| BMI | 29.2±7.1 | 29.5±7.6 | 29.6±7.5 | 0.67 | 28.6±7.3 | 30.5±7.7 | 29.2±6.6 | 0.04 |
| Disabled | 11 | 11 | 10 | 0.79 | 24 | 12 | 17 | 0.01 |
| Medication at entry | ||||||||
| Prednisone | 35 | 33 | 33 | 0.80 | 35 | 35 | 33 | 0.81 |
| Methotrexate | 68 | 61 | 68 | 0.05 | 53 | 63 | 60 | 0.13 |
| Methotrexate dose | ||||||||
| ≤7.5 mg | 22% | 17% | 28% | 24% | 15% | 23% | ||
| 10–17.5 mg | 43% | 49% | 38% | 37% | 48% | 36% | ||
| ≥20 mg | 35% | 34% | 35% | 40% | 36% | 41% | ||
| No of previous DMARD | 0.7±1.0 | 0.7±1.0 | 0.7±1.0 | 0.73 | 2.1±1.4 | 1.5±1.3 | 1.8±1.3 | <0.001 |
Data shown are percentages of patients or mean±SD.
↵* Second-time switchers, including 103 switched to adalimumab, 21 to etanercept and 27 to infliximab, are not included due to relatively small sample size.
↵† p Values are derived from analysis of variance for continuous measures and Fisher's exact test for dichotomous variables.
‡ Categories are not mutually exclusive.
ADA, adalimumab; BMI, body mass index; CDAI, clinical disease activity index; DAS28, disease activity score employing 28-joint count; DMARD, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; ETA, etanercept; INF, infliximab; mHAQ, modified health assessment questionnaire; RA, rheumatoid arthritis; TNF, tumour necrosis factor.