Multimodal nature of pain syndrome in patients with rheumatoid arthritis in relation to the course of the disease and clinical characteristics

Purpose of the study. To evaluate the character of pain syndrome in patients with rheumatoid arthritis in correlation with the course of the disease and comorbid pathology.Material and methods. Sixty-six patients with a verified diagnosis of RA were examined. Of them 84.9% were women (n=56) and 15.1% men (n=10). The median age was 59 [52; 63] years. Disease activity was assessed by DAS28-CRP, with a median of 5.2 [4.54; 6.0]. Patients with moderate (31.8%) and high activity (57.5%) predominated. Disease duration averaged Me 156 [93; 246] months. Seropositive RA was suffered by 89.3% of patients. The distribution by radiological stage was as follows: 2 radiological stage – 36.3% (n=24), 3 radiological stage – 30.3% (n=20), 4 radiological stage – 33.4% (n=22). Baseline anti-inflammatory therapy was taken by 84.8% of patients (n=56), genetically engineered biological drugs were received by 28.7% (n=16). To assess the multicomponent nature of pain syndrome, the following were used: Pain Detect questionnaire — to verify neuropathic pain (NP), CSI questionnaire — to verify central sensitisation (CS). The EQ-5D-3L questionnaire was used to assess quality of life, and the Charlson index was used to assess comorbid pathology. Structural changes were assessed by modified Sharpe method on hand and foot radiographs, synovium vascularisation was assessed by joint ultrasound.Results. 84.8% of patients had pain syndrome of mixed nature. NP correlated with pain intensity by VAS (rSp=0.458, p<0.001), DAS28-CRP (rSp=0.509, p<0.001), number of peripheral arthritis (rSp=0, 414, p<0.001), number of comorbidities (rSp=0.337, p=0.006), Charlson index (rSp=0.323, p=0.009), EQ-5D-3L (rSp= –0.268, p=0.031). CS–with VAS pain intensity (rSp=0.250, p=0.045), DAS28-CRP (rSp=0.251, p=0.044), number of painful joints (rSp=0.353, p=0.004), number of comorbidities (rSp=0.368, p=0.003), BMI (rSp=0.266, p=0.032), systolic blood pressure level (rSp=0.403, p<0.001), number of erosions on hand and foot radiographs (rSp= –0.299, p=0.016), EQ-5D-3L (rCp= –0.408, p<0.001). Patients with the presence of synovial vascularization by ultrasound had three-component pain in more than half of cases, and the combination of inflammatory pain and CS did not occur in them.Conclusions. 84.8% of patients had multicomponent pain, with pain associated only with clinical parameters of disease activity. Associated pathology and local chronic inflammation in the joint potentiate the development of other types of pain and have a mutual negative influence.