Patient population. Statistically significant differences (p < 0.05) are depicted in bold type.
| Feature | Entire Group, n = 187 | TMJ Arthritis-negative, n = 106 | TMJ Arthritis-positive, n = 81 | p |
|---|---|---|---|---|
| Demographics | ||||
| Age at diagnosis, yrs; mean, SEM, range | 6.7, 0.31, 1–15 | 6.0, 0.40, 1–15 | 7.6, 0.46, 1–15 | 0.006 |
| Disease duration*, yrs; mean, SEM, range | 2.5, 0.3, 0–17 | 3.1, 0.38, 0–14 | 1.6, 0.31, 0–17 | 0.005 |
| Newly diagnosed (< 3 mo) | 56, 30 | 28, 26 | 28, 35 | 0.228 |
| Age at study, yrs; mean, SEM, range | 9.1, 0.34, 1.7–21 | 9.1, 0.50, 1.7–2.1 | 9.2, 0.45, 2–18 | 0.794 |
| Female, n, % | 116, 62 | 63, 59 | 53, 65 | 0.402 |
| Race, n (%) | 0.981 | |||
| White | 162, 87 | 92, 87 | 70, 86 | |
| African-American | 23, 12 | 13, 12 | 10, 12 | |
| Other | 2, 1.0 | 1, 0.9 | 1, 1.2 | |
| JIA subtype, n, % | 0.251 | |||
| Oligoarticular JIA | 56, 30 | 31, 29 | 25, 31 | |
| RF– polyarticular JIA | 35, 19 | 18, 17 | 17, 21 | |
| RF+ polyarticular JIA | 3, 1.6 | 1, 0.9 | 2, 2.5 | |
| Psoriatic JIA | 37, 20 | 23, 22 | 14, 17 | |
| Enthesitis-related arthritis | 40, 21 | 25, 24 | 15, 18 | |
| Systemic-onset JIA | 12, 6.4 | 8, 7.5 | 4, 4.9 | |
| Undifferentiated | 4, 2.1 | 0 | 4, 4.9 | |
| Laboratory studies | ||||
| Positive ANA | 39/164, 24 | 23/92, 25 | 16/72, 22 | 0.678 |
| Positive RF | 6/118, 5.1 | 3/63, 4.8 | 3/55, 5.5 | 1.000 |
| ACPA | 4/50, 8.0 | 1/23, 4.3 | 3/27, 11 | 0.617 |
| Positive HLA-B27 | 17/104, 16 | 11/54, 20 | 6/50, 12 | 0.249 |
| Medications, n, % | ||||
| NSAID | 125, 67 | 77, 73 | 48, 59 | 0.054 |
| MTX | 110, 59 | 68, 64 | 42, 52 | 0.090 |
| Sulfasalazine | 2, 1.1 | 0 | 2, 2.5 | 0.186 |
| Leflunomide | 2, 1.1 | 2, 1.9 | 0 | 0.506 |
| Any anti-TNF | 84, 45 | 50, 47 | 34, 42 | 0.479 |
| Anakinra | 9, 4.8 | 5, 4.7 | 4, 4.9 | 1.000 |
| Combination DMARD | 80, 43 | 49, 46 | 31, 38 | 0.276 |
| MTX and anti-TNF | 70, 37 | 42, 40 | 28, 35 | 0.479 |
| MTX and anakinra | 8, 4.3 | 5, 4.7 | 3, 3.7 | 1.000 |
| Any DMARD | 126, 67 | 76, 72 | 50, 62 | 0.150 |
| Oral corticosteroids | 32, 17 | 19, 18 | 13, 16 | |
| Physical examination, n, % | ||||
| Mouth opening deviation | 53, 28 | 13, 12 | 40, 49 | < 0.001 |
| MIO, mm; mean, SEM, range | ||||
| Age 0–7.9 | 41.3, 0.74, 23–54 | 43.1, 0.86, 34–54 | 38.9, 1.2, 23–49 | 0.004 |
| Age 8+ | 45.8, 0.77, 30–65 | 47.8, 1.1, 31–65 | 43.6, 0.97, 30–62 | 0.005 |
| Low MIO for age** | 48, 27 | 21/99, 21 | 27/81, 33 | 0.067 |
| Mouth opening deviation or low MIO | 81, 43 | 30, 28 | 51, 63 | < 0.001 |
| Overall joint count†; mean, SEM, range | 2.2, 0.32, 0–34 | 2.0, 0.31, 0–16 | 2.6, 0.61, 0–34 | 0.358 |
| Joint count 0† | 73, 39 | 37, 35 | 36, 44 | 0.185 |
| Joint count 1 or lower† | 115, 62 | 63, 59 | 52, 64 | 0.507 |
| Joint count 4 or lower† | 165, 88 | 94, 89 | 71, 88 | 0.829 |
↵* Elapsed time between diagnosis of JIA and the initial MRI.
↵** Defined as < 2 SD below norm for age20.
↵† Total joint count is exclusive of the TMJ itself. TMJ: temporomandibular joint; ANA: antinuclear antibody; ACPA: anticitrullinated protein antibodies; DMARD: disease-modifying antirheumatic drug (includes methotrexate, sulfasalazine, leflunomide, and biologic); JIA: juvenile idiopathic arthritis; MIO: maximal incisal opening; MTX: methotrexate; NSAID: nonsteroidal antiinflammatory drugs; RF: rheumatoid factor; TNF: tumor necrosis factor.