Table 1.
Baseline characteristics of the Rasch population stratified by disease activity level
| low | n | moderate | n | high | n | p-value | |
|---|---|---|---|---|---|---|---|
| RA | |||||||
| Age (yrs) | 60(53.5–65) | 100 | 61(53–68.5) | 100 | 59(50–68.5) | 100 | 0.84 |
| Duration (yrs) | 8(3–17) | 93 | 5.5(2–14) | 92 | 5(1–14) | 92 | 0.03a |
| PDQ score | 8(5–14) | 100 | 12(7–18) | 100 | 18(12–25) | 100 | <0.01 |
| DMARD mono n (%) | 65(74) | 88 | 62(75) | 83 | 54(70) | 77 | 0.79 |
| > 1 DMARD n (%) | 23(26) | 88 | 21(25) | 83 | 23(30) | 77 | 0.79 |
| Biologics n (%) | 38(38) | 100 | 33(33) | 100 | 31(31) | 100 | 0.56 |
| DAS28-crp | 2.2(1.8–2.7) | 100 | 3.9 (3.6–4.5) | 100 | 5.7(5.4–6.25) | 100 | <0.01 |
| TJC 28 | 0(0–1) | 100 | 4(3–7.5) | 100 | 13(9–18) | 100 | <0.01 |
| SJC 28 | 0(0–0) | 100 | 1(0–3) | 100 | 5.5(2–9) | 100 | <0.01 |
| VAS pain mm | 25.5(13–41.5) | 100 | 50(32.5–65) | 100 | 75(57.5–86.5) | 100 | <0.01 |
| VAS fatigue mm | 29(18.5–56) | 100 | 54(36.5–73.5) | 100 | 77.5(57–92.5) | 100 | <0.01 |
| VAS global mm | 25.5(13.5–52.5) | 100 | 58.5(41.5–74) | 100 | 82.5(70.5–93.5) | 100 | <0.01 |
| HAQ | 0.5(0.125–1) | 99 | 1(0.625–1.375) | 99 | 1.75(1–2.25) | 100 | <0.01 |
| Crp mg/l | 3(1.5–5.5) | 100 | 7(3–14) | 100 | 23.5(11.5–39.5) | 100 | <0.01 |
| IgM-RF n (%) | 69(80) | 86 | 64(79) | 81 | 58(78) | 74 | 0.96 |
| Anti-CCP n (%) | 31(54) | 57 | 30(51) | 59 | 19(42) | 45 | 0.46 |
| PsA | |||||||
| Age (yrs) | 50.5(42–58) | 100 | 52(41.5–60) | 100 | 52(44–60) | 100 | 0.56 |
| Duration (yrs) | 6(3–9) | 91 | 4.5(1–9.5) | 92 | 6(3–9) | 87 | 0.30 |
| PDQ score | 9(5–12) | 100 | 14(9–18) | 100 | 19(14.5–24) | 100 | <0.01 |
| DMARD mono n (%) | 69 (95) | 73 | 53(83) | 64 | 54 (81) | 67 | 0.04 |
| > 1 DMARD n (%) | 4(5) | 73 | 11(17) | 64 | 13(19) | 67 | 0.04 |
| Biologics n (%) | 55(55) | 100 | 44(44) | 100 | 41(41) | 100 | 0.11 |
| DAS28-crp | 1.8(1.6–2.35) | 92 | 2.8(2.4–3.55) | 92 | 4.4(3.8–5.1) | 90 | <0.01 |
| TJC 28 | 0(0–1) | 94 | 1(0–3.5) | 92 | 5(2–12) | 91 | <0.01 |
| SJC 28 | 0(0–0) | 93 | 0(0–0) | 92 | 0(0–2) | 90 | <0.01b |
| BASDAI (0–100) | 21.5(13–28) | 98 | 52(41–64) | 98 | 77(71–85) | 99 | <0.01 |
| BASFI (0–100) | 15.5(7–27) | 98 | 45.5(27–57) | 98 | 74(62–86) | 99 | <0.01 |
| ASDAS | 1.5(1.1–1.8) | 97 | 2.8(2.5–3.1) | 97 | 4(3.7–4.5) | 98 | <0.01 |
| VAS pain mm | 20.5(12–30) | 100 | 50(39.5–63) | 100 | 77 (68–88.5) | 100 | <0.01 |
| VAS fatigue mm | 27(15–38) | 100 | 65(48–77) | 100 | 85(75–93) | 100 | <0.01 |
| VAS global mm | 22(14–30) | 100 | 59.5(46–74) | 100 | 85.5(77–94) | 100 | <0.01 |
| HAQ | 0.375(0–0.625) | 96 | 0.75(0.51.25) | 95 | 1.5(1–1.875) | 96 | <0.01 |
| Crp mg/l | 2(1–4) | 100 | 3(1.5–6) | 100 | 6(3–14) | 100 | <0.01 |
| HLA-B27 n (%) | 7(54) | 13 | 10(53) | 19 | 7(58) | 12 | 0.95 |
| SpA | |||||||
| Age (yrs) | 45.5(36–53) | 100 | 43.5 (35–52.5) | 100 | 47(37–54) | 100 | 0.52 |
| Duration (yrs) | 6(3–13) | 94 | 4.5(2–9) | 90 | 5(2–12) | 89 | 0.14 |
| PDQ score | 8(5–13.5) | 100 | 15(9–19.5) | 100 | 17.5(10.5–22.5) | 100 | <0.01 |
| DMARD mono n (%) | 24(100) | 24 | 21(84) | 25 | 26(96) | 27 | 0.06 |
| > 1 DMARD n (%) | 0 (0) | 24 | 4(16) | 25 | 1(4) | 27 | 0.06 |
| Biologics n (%) | 78(78) | 100 | 56(56) | 100 | 54(54) | 100 | <0.01c |
| BASDAI (0–100) | 22.5(14–34) | 100 | 49(39–61) | 100 | 72.5(65–83) | 100 | <0.01 |
| BASFI (0–100) | 16(10.5–31.5) | 100 | 40.5(27–56) | 100 | 67.5(49–83.5) | 100 | <0.01 |
| ASDAS | 1.7(1.3–1.90) | 100 | 2.9(2.5–3.1) | 100 | 4.1(3.8–4.5) | 100 | <0.01 |
| VAS pain mm | 21.5(12–35) | 100 | 53.5(38–72) | 100 | 75.5(65.5–86) | 100 | <0.01 |
| VAS fatigue mm | 31.5(17.5–48) | 100 | 65(45.5–81) | 100 | 83(71.5–92) | 100 | <0.01 |
| VAS global mm | 24.5(15.5–36) | 100 | 61(46–78) | 100 | 84(74–92) | 100 | <0.01 |
| Crp mg/l | 2(1–4) | 100 | 3(2–7) | 100 | 10(5–21) | 100 | <0.01 |
| HLA-B27 n (%) | 28(82) | 34 | 20(63) | 32 | 20(67) | 30 | 0.17 |
Values are the median (interquartile range) or (n (%)). P-values are calculated by Kruskal-Wallis Test, Fishers exact test or Chi square. Except where indicated otherwise there are difference/no difference across all groups according to p value. ano group difference between moderate – high disease activity p = 0.54, bno group difference between low-moderate disease activity p = 0.31, cno group difference between moderate-high disease activity p = 0.78.DMARD Disease Modifying Anti-Rheumatic Drug, DAS28-crp Disease Activity Score 28 –crp, TJC Tender Joint Count, SJC Swollen Joint Count, BASDAI Bath Ankylosing Spondylitis Disease Activity Index, BASFI Bath Ankylosing Spondylitis Functional Index, ASDAS Ankylosing Spondylitis Disease Activity Score, VAS Visual Analogue Scale, HAQ Health Assessment Questionnaire, HLA-B27 Human Leucocyte Antigen-B27, IgM-RF Immunoglobulin M Rheumatoid Factor, Anti-CCP Anti–citrullinated protein antibodies