Associations between subclinical joint inflammation scores and hand function measures, and their diagnostic characteristics for the presence of tenosynovitis
| (A) Derivation cohort | |||
| Association with subclinical joint inflammation (semiquantitative score; per point) | |||
| Dynamometer-measured GS (in kg) | Patient-reported grip difficulties (OR) | Incomplete fist closure (OR) | |
| Total inflammation score | −0.38 (−0.68 to −0.08)* | 1.12 (1.04 to 1.20)* | 0.98 (0.89 to 1.07) |
| Individual features (multivariable): | |||
| Synovitis score | 0.27 (−1.02 to 1.35) | 1.15 (0.89 to 1.50) | 0.67 (0.46 to 0.98) |
| Tenosynovitis score | −2.63 (−2.26 to −0.33)* | 1.12 (1.07 to 1.40)* | 1.36 (1.03 to 1.79)* |
| BME score | 0.96 (−0.36 to 1.04) | 1.03 (0.87 to 1.22) | 0.91 (0.68 to 1.23) |
| Diagnostic characteristic for the presence of tenosynovitis | |||
| Sensitivity (%) | 75 (67 to 83) | 54 (45 to 67) | 14 (8 to 22) |
| Specificity (%) | 25 (18 to 34) | 45 (35 to 54) | 88 (80 to 93) |
| (B) Validation cohort | |||
| Associations with subclinical joint inflammation (semiquantitative; per point) | |||
| Examiner-assessed decreased GS (OR) | Patient-reported grip difficulties (OR) | Incomplete fist closure (OR) | |
| Total inflammation score | 1.06 (1.02 to 1.11)* | 1.08 (1.02 to 1.13)* | 1.11 (1.05 to 1.17)* |
| Individual features (multivariable): | |||
| Synovitis score | 0.93 (0.77 to 1.12) | 0.97 (0.80 to 1.18) | 0.86 (0.67 to 1.11) |
| Tenosynovitis score | 1.20 (1.02 to 1.40)* | 1.17 (1.01 to 1.36)* | 1.40 (1.13 to 1.74)* |
| BME score | 1.28 (0.99 to 1.48) | 1.13 (0.94 to 1.36) | 1.14 (0.98 to 1.34) |
| Diagnostic characteristic for the presence of tenosynovitis | |||
| Sensitivity (%) | 40 (32 to 49) | 57 (48 to 67) | 22 (14 to 30) |
| Specificity (%) | 65 (60 to 69) | 52 (46 to 57) | 90 (87 to 93) |
Total inflammation score is the sum of synovitis, tenosynovitis and BME scores. Measures of hand function were analysed as the dependent variable with linear/logistic regression including total inflammation or the three separate MRI features, adjusted for age and sex. Tenosynovitis was considered present if scored by two independent readers and if detected in <5% of age-matched healthy controls as described in online supplemental appendix. For the diagnostic characteristics of tenosynovitis, dynamometer-measured GS was compared with the mean GS in healthy individuals of the same age and sex as reported by Günther et al.6
95% CI is given between the brackets.
*Denotes statistical significance.
BME, bone marrow oedema; GS, grip strength.