Pain sensitivity in young adults with juvenile idiopathic arthritis: a quantitative sensory testing study

Abstract

Background: To study for the first-time, pain perception, pain sensitivity, and self-reported pain in young adults with long disease duration of juvenile idiopathic arthritis (JIA) compared with controls.

Methods: Children from Central Norway diagnosed with JIA between 1997 and 2004 were included consecutively in a population-based prospective study. Children with onset 1997-2000 were part of the Nordic JIA cohort. Controls were age- and sex-matched. In 2015-2017, study visits with investigator-blinded quantitative sensory testing (QST) comprising cold and warm detection thresholds (CDT/WDT), cold and heat pain thresholds (CPT/HPT), pressure pain threshold (PPT), and a suprathreshold heat pain test were performed. We constructed separate multilevel models for each variable of detection and pain thresholds with interaction between groups and site adjusted for the effect of age and sex.

Results: Among 96 young adults with JIA, 71% were female, median age was 22.7 years, disease duration was 16.1 years, and 47% had oligoarticular disease. Among 109 controls, 71% were female, and median age was 23.5 years. Participants with JIA had lower pressure pain thresholds (PPTs) (95% CI) compared to controls, upper limb 888 (846,930) versus 1029 (999,1059) kPa and lower limb 702 (670,734) versus 760 (726,794) kPa. Participants with inactive disease had the lowest PPTs and cold pain thresholds (CPTs), compared to those in remission off medication and those with active disease. Minor differences were found regarding CDT/WDT and CPT/HPT in JIA compared to controls. The median (IQR) temperature needed to evoke pain = 6 on a 0-10 numeric rating scale (NRS) in the suprathreshold heat pain tests were lower in JIA than in controls (46 °C (45-47 °C) versus 47 °C (46-48 °C)). We found no associations between self-reported pain and pain thresholds.

Conclusions: Our results indicate for the first time that young adults with long disease duration of JIA may have altered pain perception and sensitivity compared to controls. A clinical implication may be the importance of early treatment to quickly achieve pain-free remission and avoid long-term pain sensitization.

Keywords: Juvenile idiopathic arthritis (JIA); Long-term outcomes; Pain perception; Pain sensitivity; Pain sensitization; Pain threshold; Quantitative sensory testing (QST); Self-reported pain; Young adults.

Fig. 1

An illustration of the distribution of cold, heat, and pressure pain thresholds (CPT, HPT, and PPT) at upper and lower limb in young adults with juvenile idiopathic arthritis (JIA) and age- and sex-matched controls. The dot-plot illustrating the distribution within each group as dots, and the group median indicated with the horizontal spiked line

Fig. 3

Pain scores during 120-s continuous suprathreshold heat pain stimulation in young adults with juvenile idiopathic arthritis (JIA) and age- and sex-matched controls. Pain scores were measured with numeric rating scale (NRS), range 0–10 (0 = no pain, 10 = unbearable pain). The estimated margins of the multilevel model are graphically illustrated with time on the x-axis and NRS scores on the y-axis. In both groups, the NRS scores increased during the 120-s stimulation, but it was a trend towards steeper increase in the JIA group

Fig. 2

Graphic illustration of cold, heat, and pressure pain thresholds (CPT, HPT, and PPT) in JIA and controls as estimated margins with 95% CI from the multilevel models, adjusted for age and sex. The y-axis represents absolute temperature (°C) in CPT and HPT and kilopascal (kPa) in PPT. Since the censored CPT values are accounted for in the estimated margins of CPT, these results are not directly comparable with the results in Fig. 1 and Supplementary Table S2