Table 1.
Participant demographics, clinical characteristics, and inflammation
| Rheumatoid arthritis (n = 50) |
Controls (n = 39) |
|
|---|---|---|
| Age (years) | 55.4 ± 12.8 | 52.1 ± 11.4 |
| Gender | ||
| Female | 35 (70 %) | 27 (69 %) |
| Male | 15 (30 %) | 12 (31 %) |
| Race | ||
| Pacific Islander | 1 (2 %) | 0 (0 %) |
| African American | 14 (28 %) | 12 (31 %) |
| Caucasian | 35 (70 %) | 27 (69 %) |
| Clinical characteristics | ||
| BMI (kg/m2) | 30.5 ± 7.5 | 29.0 ± 5.3 |
| Waist circumference (cm) | 95.3 ± 16.7 | 85.0 ± 27.9 |
| HAQ-DI | 0.7 ± 0.7*** | 0 ± 0 |
| Pain (VAS) (mm) | 40.1 ± 28.9*** | 9.8 ± 2.4 |
| Comorbidity index | 1.6 ± 1.2** | 0.6 ± 0.9 |
| DASESR-28 | 3.0 ± 1.4 | NA |
| Remission (DAS <2.6) | 19 (40 %) | |
| Low activity (DAS 2.6–3.2) | 8 (17 %) | |
| Moderate activity (DAS 3.2–5.1) | 16 (33 %) | |
| High activity (DAS >5.1) | 5 (10 %) | |
| RF positive | 41/46 | NA |
| Anti-CCP positive | 20/21 | NA |
| Radiograph erosions present | 21/38 | NA |
| Medication use | ||
| Etanercept | 10 (20 %) | NA |
| Infliximab | 2 (4 %) | NA |
| Adalimumab | 5 (10 %) | NA |
| Abatacept | 5 (10 %) | NA |
| Methotrexate | 38 (76 %) | NA |
| Leflunomide | 1 (2 %) | NA |
| Sulfasalazine | 0 | NA |
| Hydroxychloroquine | 10 (20 %) | NA |
| NSAID | 18 (36 %) | NA |
| Prednisone | 12 (24 %) | NA |
| Systemic inflammation (mean ± SEM) | ||
| ESR (mm/hour) | 11.9 ± 1.7* | 7.6 ± 2.6 |
| hsCRP (mg/l) | 7.9 ± 1.2** | 3.2 ± 0.7 |
| IL-1β (pg/ml) | 0.8 ± 0.2* | 0.7 ± 0.2 |
| IL-6 (pg/ml) | 19.8 ± 7.3*** | 3.1 ± 0.3 |
| IL-8 (pg/ml) | 10.9 ± 1.1* | 17.8 ± 8.0 |
| IL-18 (pg/ml) | 464.2 ± 21.1** | 390.8 ± 21.8 |
| TNFα (pg/ml) | 31.5 ± 5.0*** | 11.4 ± 8.6 |
| Metabolic | ||
| Fasting insulin (mU/l) | 7.5 ± 7.5 | 7.5 ± 5.6 |
| Fasting glucose (mg/dl) | 89.9 ± 13.6* | 97.2 ± 11.4 |
| HOMA | 1.7 ± 1.8 | 1.8 ± 1.5 |
| IS index (×10–5.min−1/(pmol/l)) | ||
| Women | 6.8 ± 6.5 | 8.4 ± 10.4 |
| Men | 4.2 ± 3.3 | 5.3 ± 3.3 |
| Acute insulin response (pmol/l) | 481 ± 523 | 324 ± 230 |
| Adiposity and muscle | ||
| Abdominal | ||
| Total adipose area (cm2) | 411 ± 201 | 400 ± 157 |
| Subcutaneous adiposity (cm2) | 306 ± 155 | 275 ± 132 |
| Visceral adiposity (cm2) | 105 ± 86 | 125 ± 96 |
| Liver density (Hu) | 60 ± 11 | 59 ± 12 |
| Thigh | ||
| Total thigh area (cm2) | 250 ± 74 | 244 ± 59 |
| Subcutaneous adiposity (cm2) | 124 ± 63 | 108 ± 51 |
| Intermuscular adiposity (cm2) | 12 ± 7 | 12 ± 8 |
| Muscle area (cm2) | 115 ± 37 | 124 ± 32 |
| Muscle density (Hu) | 51 ± 6 | 52 ± 4 |
Data presented as mean ± standard deviation or frequency (percentage) unless otherwise stated
*P <0.05, **P <0.01, ***P <0.001 as compared with controls
BMI body mass index, CCP cyclic citrullinated peptide, DAS Disease Activity Score, DAS ESR -28 Disease Activity Score with 28-joint count using the erythrocyte sedimentation rate, ESR erythrocyte sedimentation rate, HAQ-DI Health Assessment Questionnaire—Disability Index, HOMA homeostasis model assessment, hsCRP high-sensitivity C-reactive protein, IL interleukin, IS insulin sensitivity, NSAID nonsteroidal anti-inflammatory drug, RF rheumatoid factor, SEM standard error of the mean, TNFα tumor necrosis factor alpha, VAS visual analog scale, NA not applicable