Table 3.
Thermal pain thresholds and pressure pain thresholds among juvenile idiopathic arthritis (JIA) and controls*
| n | Cold pain thresholda | Heat pain threshold | Pressure pain threshold | ||||
|---|---|---|---|---|---|---|---|
| Absolute temperature °C (95% CI) | Absolute temperature °C (95% CI) | Kilopascal (95% CI) | |||||
| Upper limb | Lower limb | Upper limb | Lower limb | Upper limb | Lower limb | ||
| Control | 109 | 15.9 (13.8, 18.0) | 13.2 (11.1, 15.3) | 44.3 (43.6, 45.0) | 44.9 (44.3, 45.4) | 1029 (999, 1059) | 760 (726, 794) |
| JIA (total group)b | 96 | 15.5 (13.1, 17.8) | 13.4 (11.1, 15.8) | 44.0 (43.1, 44.8) | 44.8 (44.2, 45.4) | 888 (846, 930) | 702 (670, 734) |
| p = 0.8 | p = 0.9 | p = 0.5 | p = 0.8 | p < 0.001 | p = 0.01 | ||
| JIA | |||||||
| Remission off med.c | 43 | 14.3 (10.7, 17.8) | 11.8 (8.2, 15.4) | 43.6 (42.2, 45.0) | 44.8 (43.8, 45.8) | 893 (823, 962) | 731 (674, 788) |
| p = 0.4 | p = 0.5 | p = 0.4 | p = 0.9 | p < 0.001 | p = 0.4 | ||
| Inactive diseasec | 20 | 16.9 (11.9, 22.0) | 17.4 (12.4, 22.4) | 44.2 (42.4, 46.0) | 44.9 (43.5, 46.3) | 836 (761, 910) | 626 (574, 677) |
| p = 0.7 | p = 0.1 | p = 0.9 | p = 1.0 | p < 0.001 | p < 0.001 | ||
| Active diseasec | 33 | 16.2 (12.4, 20.0) | 13.1 (9.2, 17.0) | 44.3 (43.1, 45.4) | 44.6 (43.9, 45.3) | 910 (842, 978) | 707 (662, 752) |
| p = 0.9 | p = 1.0 | p = 0.9 | p = 0.6 | p = 0.002 | p = 0.06 | ||
*Multilevel modeling with predicted values as absolute temperature with 95% CI, adjusted for age and sex
CI confidence interval, p p value comparing controls with JIA disease group (either total group or according to disease status)
aA substantial number were censored because the participants did not reach their cold pain thresholds due to floor temperature of the hardware was 5 °C; 212 (28%) in the JIA group and 198 (23%) in the control group. We accounted for these censored responses in the statistical analyses
bSeparate multilevel model of the total JIA cohort
cDisease status according to the definition by Wallace et al. Remission off med. remission off medication for ≥ 12 months, Inactive disease inactive disease on medication for less than 6 months or inactive disease off medication for less than 12 months or remission on medication (inactive disease on medication for more than 6 months). Active disease flare or continuous active disease